then to Egypt Greece France Spain America c. and the like holdeth in the Moon and the rest of the Coelestial Bodies which self same effect falls out exactly in the same manner if without troubling so great a part of the Universe the Terrestrial Globe be made to revolve in it self But we will augment the difficulty by the addition of this other which is a very great one namely that if you will ascribe this Great Motion to Heaven you must of necessity make it contrary to the particular motion of all the Orbs of the Planets each of which without controversie hath its peculiar motion from the West towards the East and this but very easie and moderate and then you make them to be hurried to the contrary part i. e. from East to West by this most furious diurnal motion whereas on the contrary making the Earth to move in it self the contrariety of motions is taken away and the onely motion from West to East is accommodated to all appearances and exactly satisfieth every Phoenomenon SIMPL. As to the contrariety of Motions it would import little for Aristotle demonstrateth that circular motions are not contrary to one another and that theirs cannot be truly called contrariety SALV Doth Aristotle demonstrate this or doth he not rather barely affirm it as serving to some certain design of his If contraries be those things that destroy one another as he himself affirmeth I do not see how two moveables that encounter each other in a circular line should lesse prejudice one another than if they interfered in a right line SAGR. Hold a little I pray you Tell me Simplicius when two Knights encounter each other tilting in open field or when two whole Squadrons or two Fleets at Sea make up to grapple and are broken and sunk do you call these encounters contrary to one another SIMPL. Yes we say they are contrary SAGR. How then is there no contrariety in circular motions These motions being made upon the superficies of the Earth or Water which are as you know spherical come to be circular Can you tell Simplicius which those circular motions be that are not contrary to each other They are if I mistake not those of two circles which touching one another without one thereof being turn'd round naturally maketh the other move the contrary way but if one of them shall be within the other it is impossible that their motion being made towards different points they should not justle one another SALV But be they contrary or not contrary these are but alterations of words and I know that upon the matter it would be far more proper and agreeable with Nature if we could salve all with one motion onely than to introduce two that are if you will not call them contrary opposite yet do I not censure this introduction of contrary motions as impossible nor pretend I from the denial thereof to inferre a necessary Demonstration but onely a greater probability of the other A third reason which maketh the Ptolomaique Hypothesis lesse probable is that it most unreasonably confoundeth the order which we assuredly see to be amongst those Coelestial Bodies the circumgyration of which is not questionable but most certain And that Order is that according as an Orb is greater it finisheth its revolution in a longer time and the lesser in shorter And thus Saturn describing a greater Circle than all the other Planets compleateth the same in thirty yeares Jupiter finisheth his that is lesse in twelve years Mars in two The Moon runneth thorow hers so much lesse than the rest in a Moneth onely Nor do we lesse sensibly see that of the Medicean Stars which is nearest to Jupiter to make its revolution in a very short time that is in four and forty hours or thereabouts the next to that in three dayes and an half the third in seven dayes and the most remote in sixteen And this rate holdeth well enough nor will it at all alter whilest we assign the motion of 24 hours to the Terrestrial Globe for it to move round its own center in that time but if you would have the Earth immoveable it is necessary that when you have past from the short period of the Moon to the others successively bigger until you come to that of Mars in two years and from thence to that of the bigger Sphere of Jupiter in twelve years and from this to the other yet bigger of Saturn whose period is of thirty years it is necessary I say that you passe to another Sphere incomparably greater still than that and make this to accomplish an entire revolution in twenty four hours And this yet is the least disorder that can follow For if any one should passe from the Sphere of Saturn to the Starry Orb and make it so much bigger than that of Saturn as proportion would require in respect of its very slow motion of many thousands of years then it must needs be a Salt much more absurd to skip from this to another bigger and to make it convertible in twenty four hours But the motion of the Earth being granted the order of the periods will be exactly observed and from the very slow Sphere of Saturn we come to the fixed Stars which are wholly immoveable and so avoid a fourth difficulty which we must of necessity admit if the Starry Sphere be supposed moveable and that is the immense disparity between the motions of those stars themselves of which some would come to move most swiftly in most vast circles others most slowly in circles very small according as those or these should be found nearer or more remote from the Poles which still is accompanied with an inconvenience as well because we see those of whose motion there is no question to be made to move all in very immense circles as also because it seems to be an act done with no good consideration to constitute bodies that are designed to move circularly at immense distances from the centre and afterwards to make them move in very small circles And not onely the magnitudes of the circles and consequently the velocity of the motions of these Stars shall be most different from the circles and motions of those others but which shall be the fifth inconvenience the self-same Stars shall successively vary its circles and velocities For that those which two thousand years since were in the Equinoctial and consequently did with their motion describe very vast circles being in our dayes many degrees distant from thence must of necessity become more slow of motion and be reduced to move in lesser circles and it is not altogether impossible but that a time may come in which some of them which in aforetime had continually moved shall be reduced by uniting with the Pole to a state of rest and then after some time of cessation shall return to their motion again whereas the other Stars
much trouble or difficulty master the roughnesses of these novel and fantastical opinions SALV If that which Gilbert writeth be true then is it no opinion but the subject of Science nor is it new but as antient as the Earth it self nor can it being true be rugged or difficult but plain and easie and when you please I shall make you feel the same in your hand for that you of your self fancy it to be a Ghost and stand in fear of that which hath nothing in it of dreadfull like as a little child doth fear the Hobgoblin without knowing any more of it save the name as that which besides the name is nothing SIMP I should be glad to be informed and reclaimed from an errour SALV Answer me then to the questions that I shall ask you And first of all Tell me whether you believe that this our Globe which we inhabit and call Earth consisteth of one sole and simple matter or else that it is an aggregate of matters different from each other SIMP I see it to be composed of substances and bodies very different and first for the greatest parts of the composition I see the Water and the Earth which extreamly differ from one another SALV Let us for this once lay aside the Seas and other Waters and let us consider the solid parts and tell me if you think them one and the same thing or else different SIMP As to appearance I see that they are different things there being very great heaps of unfruitful sands and others of fruitful soiles There are infinite sharp and steril mountains full of hard stones and quarries of several kinds as Porphyre Alablaster Jasper and a thousand other kinds of Marbles There are vast Minerals of so many kinds of metals and in a word such varieties of matters that a whole day would not suffice only to enumerate them SALV Now of all these different matters do you think that in the composition of this grand masse there do concur portions or else that amongst them all there is one part that far exceeds the rest and is as it were the matter and substance of the immense lump SIMP I believe that the Stones Marbles Metals Gems and the so many other several matters are as it were Jewels and exteriour and superficial Ornaments of the primary Globe which in grosse as I believe doth without compare exceed all these things put together SALV And this principal and vast masse of which those things above named are as it were excressences and ornaments of what matter do you think that it is composed SIMP I think that it is the simple or lesse impure element of Earth SALV But what do you understand by Earth Is it haply that which is dispersed all over the fields which is broke up with Mattocks and Ploughs wherein we sowe corne and plant fruits and in which great boscages grow up without the help of culture and which is in a word the habitation of all animals and the womb of all vegetables SIMP T is this that I would affirm to be the substance of this our Globe SALV But in this you do in my judgment affirm that which is not right for this Earth which is broke up is sowed and is fertile is but one part and that very small of the surface of the Globe which doth not go very deep yea its depth is very small in comparison of the distance to the centre and experience sheweth us that one shall not dig very low but one shall finde matters very different from this exteriour scurf more solid and not good for the production of vegetables Besides the interne parts as being compressed by very huge weights that lie upon them are in all probability slived and made as hard as any hard rock One may adde to this that fecundity would be in vain conferred upon those matters which never were designed to bear fruit but to rest eternally buried in the profound and dark abysses of the Earth SIMP But who shall assure us that the parts more inward and near to the centre are unfruitful They also may perhaps have their productions of things unknown to us SALV You may aswell be assured thereof as any man else as being very capable to comprehend that if the integral bodies of the Universe be produced onely for the benefit of Mankind this above all the rest ought to be destin'd to the sole conveniences of us its inhabitants But what benefit can we draw from matters so hid and remote from us as that we shall never be able to make use of them Therefore the interne substance of this our Globe cannot be a matter frangible dissipable and non-coherent like this superficial part which we call EARTH but it must of necessity be a most dense and solid body and in a word a most hard stone And if it ought to be so what reason is there that should make you more scrupulous to believe that it is a Loadstone than a Porphiry a Jasper or other hard Marble Happily if Gilbert had written that this Globe is all compounded within of Pietra Serena or of Chalcedon the paradox woulâ— have seemed to you lesse exorbitant SIMP That the parts of this Globe more intern are more compressed and so more slived together and solid and more and more so according as they lie lower I do grant and so likewise doth Aristotle but that they degenerate and become other than Earth of the same sort with this of the superficial parts I see nothing that obliegeth me to believe SALV I undertook not this discourse with an intent to prove demonstratively that the primary and real substance of this our Globe is Load-stone but onely to shew that no reason could be given why one should be more unwilling to grant that it is of Load-stone than of some other matter And if you will but seriously consider you shall find that it is not improbable that one sole pure and arbitrary name hath moved men to think that it consists of Earth and that is their having made use commonly from the beginning of this word Earth as well to signifie that matter which is plowed and sowed as to name this our Globe The denomination of which if it had been taken from stone as that it might as well have been taken from that as from the Earth the saying that its primary substance was stone would doubtlesse have found no scruple or opposition in any man And is so much the more probable in that I verily believe that if one could but pare off the scurf of this great Globe taking away but one full thousand or two thousand yards and afterwards seperate the Stones from the Earth the accumulation of the stones would be very much biger than that of the fertile Mould But as for the reasons which concludently prove de facto that is our Globe is a Magnet I have mentioned none of them nor is this a time to alledg
do not happen in our Mediterranean Sea yet doth not this invalidate the reason and cause that I shall produce if so be that it verifie and fully resolve the accidents which evene in our Sea for that in conclusion there can be but one true and primary cause of the effects that are of the same kind I will relate unto you therefore the effects that I know to be true and assigne the causes thereof that I think to be true and you also Gentlemen shall produce such others as are known to you besides mine and then we will try whether the cause by me alledged may satisfie them also I therefore affirm the periods that are observed in the fluxes and refluxes of the Sea-waters to be three the first and principal is this great and most obvious one namely the diurnal according to which the intervals of some hours with the waters flow and ebbe and these intervals are for the most part in the Mediterrane from six hours to six hours or thereabouts that is they for six hours flow and for six hours ebbe The second period is monethly and it seemes to take its origen from the motion of the Moon not that it introduceth other motions but only altereth the greatnesse of those before mentioned with a notable difference according as it shall wax or wane or come to the Quadrature with the Sun The third Period is annual and is seen to depend on the Sunne and onely altereth the diurnal motions by making them different in the times of the Solstices as to greatnesse from what they are in the Equinoxes We will speak in the first place of the diurnal motion as being the principal and upon which the Moon and Sun seem to exercise their power secondarily in their monethly and annual alterations Three differences are observable in these horary mutations for in some places the waters rise and fall without making any progressive motion in others without rising or falling they run one while towards the East and recur another while towards the West and in others they vary the heights and course also as happeneth here in Venice where the Tides in coming in rise and in going out fall and this they do in the extermities of the lengths of Gulphs that distend from West to East and terminate in open shores up along which shores the Tide at time of flood hath room to extend it self but if the course of the Tide were intercepted by Cliffes and Banks of great height and steepnesse there it will flow and ebbe without any progressive motion Again it runs to and again without changing height in the middle parts of the Mediterrane as notably happeneth in the Faro de Messina between Scylla and Carybdis where the Currents by reason of the narrownesse of the Channel are very swift but in the more open Seas and about the Isles that stand farther into the Mediterranean Sea as the Baleares Corsica Sardignia Elba Sicily towards the Affrican Coasts Malta Candia c. the changes of watermark are very small but the currents indeed are very notable and especially when the Sea is pent between Islands or between them and the Continent Now these onely true and certain effects were there no more to be observed do in my judgment very probably perswade any man that will contain himself within the bounds of natural causes to grant the mobility of the Earth for to make the vessel as it may be called of the Mediterrane stand still and to make the water contained therein to do as it doth exceeds my imagination and perhaps every mans else who will but pierce beyond the rinde in these kind of inquiries SIMP These accidents Salviatus begin not now they are most ancient and have been observed by very many and several have attempted to assigne some one some another cause for the same and there dwelleth not many miles from hence a famous Peripatetick that alledgeth a cause for the same newly fished out of a certain Text of Aristotle not well understood by his Expositors from which Text he collecteth that the true cause of these motions doth only proceed from the different profundities of Seas 〈…〉 waters of greatest depth being greater in abundance and therefore more grave drive back the Waters of lesse depth which being afterwards raised desire to descend and from this continual colluctation or contest proceeds the ebbing and flowing Again those that referre the same to the Moon are many saying that she hath particular Domination over the Water and at last a certain Prelate hath published a little Treatise wherâ—in he saith that the Moon wandering too and fro in the Heavens attracteth and draweth towards it a Masse of Water which goeth continually following it so that it is full Sea alwayes in that part which lyeth under the Moon and because that though she be under the Horizon yet neverthelesse the Tide returneth he saith that no more can be said for the salving of that particular save onely that the Moon doth not onely naturally retain this faculty in her self but in this case hath power to confer it upon that degree of the Zodiack that is opposite unto it Others as I believe you know do say that the Moon is able with her temperate heat to rarefie the Water which being rarefied doth thereupon flow Nor hath there been wanting some that SAGR. I pray you Simplicius let us hear no more of them for I do not think it is worth the while to wast time in relating them or to spend our breath in confuting them and for your part if you gave your assent to any of these or the like fooleâ—ies you did a great injury to your judgment which neverthelesse I acknowledg to be very piercing SALV But I that am a little more flegmatick than you Sagredus will spend a few words in favour of Simplicius if haply he thinks that any probability is to be found in those things that he hath related I say therefore The Waters Simplicius that have their exteriour superficies higher repel those that are inferiour to them and lower but so do not those Waters that are of greatest profundity and the higher having once driven back the lower they in a short time grow quiet and level This your Peripatetick must needs be of an opinion that all the Lakes in the World that are in a calme and that all the Seas where the ebbing and flowing is insensible are level in their bottoms but I was so simple that I perswaded my self that had we no other plummet to sound with the Isles that advance so high above Water had been a sufficient evidence of the unevennesse of their bottomes To that Prelate I could say that the Moon runneth every day along the whole Mediterrane and yet its Waters do not rise thereupon save onely in the very extream bounds of it Eastward and here to us at Venice And for those that make the Moons
haply many others also undiscovered It is to be supposed that the first observers of Heaven knew no more but one motion common to all the Stars as is this diurnal one yet I believe that in few dayes they perceived that the Moon was inconstant in keeping company with the other Stars but yet withal that many years past before that they distinguished all the Planets And in particular I conceit that Saturn by its slowness and Mercury by reason of its seldom appearing were the last that were observed to be wandring and errant It is to be thought that many more years run out before the statioâ—s and retrogradations of the three superiour Planets were known as also their approximations and recessions from the Earth necessary occasions of introducing the Eccentrix and Epicicles things unknown even to Aristotle for that he makes no mention thereof Mercury and Venus with their admirable apparitions how long did they keep Astronomers in suspence before that they could resolve not to speak of any other of their qualities upon their situation Insomuch that the very order onely of the Mundane bodies and the integral structure of the parts of the Universe by us known hath been doubted of untill the time of Copernicus who hath at last given us notice of the true constitution and real systeme according to which those parts are disposed so that at length we are certain that Mercury Venus and the other Planets do revolve about the Sun and that the Moon revolveth about the Earth But how each Planet governeth it self in its particular revolution and how precisely the structure of its Orb is framed which is that which is vulgarly called the Theory of the Planets we cannot as yet undoubtedly resolve Mars that hath so much puzled our Modern Astronomers is a proof of this And to the Moon her self there have been assigned several Theories after that the said Copernicus had much altered it from that of Ptolomy And to descend to our particular case that is to say to the apparent motion of the Sun and Moon touching the former there hath been observed a certain great irregularity whereby it passeth the two semicircles of the Ecliptick divided by the points of the Equinoxes in very different times in passing one of which it spendeth about nine dayes more than in passing the other a difference as you see very great and notable But if in passing small arches such for example as are the twelve Signs he maintain a most regular motion or else proceed with paces one while a little more swift and another more slow as it is necessary that it do in case the annual motion belong to the Sun onely in appearance but in reality to the Earth in company with the Moon it is what hath not hitherto been observed nor it may be sought Touching the Moon in the next place whose restitutions have been principally lookt into an account of the Eclipses for which it is sufficient to have an exact knowledge of its motion about the Earth it hath not been likewise with a perfect curiosity inquired what itâ— course is thorow the particular arches of the Zodiack That therefore the Earth and Moon in running through the Zodiack that is round the Grand Orb do somewhat accellerate at the Moons change and retard at its full ought not to be doubted for that the said difference is not manifest which cometh to be unobserved upon two accounts First Because it hath not been lookt for Secondly Because that its possible it may not be very great Nor is there any need that it should be great for the producing the effect that we see in the alteration of the greatness of ebbings and flowings For not onely those alterations but the Tides themselves are but small matters in respect of the grandure of the subjects on which they work albeit that to us and to our littleness they seem great For the addition or subduction of one degree of velocity where there are naturally 700 or 1000 can be called no great alteration either in that which conferreth it or in that Which receiveth it the Water of our Mediterrane carried about by the diurnal revolution maketh about 700 miles an hour which is the motion common to the Earth and to it and therefore not perceptible to us that which we sensibly discern to be made in the streams or currents is not at the rate of full one mile an hour I speak of the main Seas and not of the Straights and this is that which altereth the first naturall and grand motion and this motion is very great in respect of us and of Ships for a Vessel that in a standing Water by the help of Oares can make v. g. three miles an hour in that same current will row twice as far with the stream as against it A notable difference in the motion of the Boat though but very small in the motion of the Sea which is altered but its seven hundredth part The like I say of its rising and falling one two or three feet and scarcely four or five in the utmost bounds of a streight two thousand or more miles long and where there are depths of hundreds of feet this alteration is much less than if in one of the Boats that bring us fresh Water the said Water upon the arrest of the Boat should rise at the Prow the thickness of a leaf I conclude therefore that very small alterations in respect of the immense greatness and extraordinary velocity of the Seas is sufficient to make therein great mutations in relation to our smallness and to our accidents SAGR. I am fully satisfied as to this particular it remains to declare unto us how those additions and substractions derived from the diurnal Vertigo are made one while greater and another while lesser from which alterations you hinted that the annual period of the augmentations and diminutions of the ebbings and flowings did depend SALV I will use my utmost endeavours to render my self intelligible but the difficulty of the accident it self and the great attention of mind requisite for the comprehending of it constrains me to be obscure The unequalities of the additions and substractions that the diurnal motion maketh to or from the annual dependeth upon the inclination of the Axis of the diurnal motion upon the plane of the Grand Orb or if you please of the Ecliptick by means of which inclination the Equinoctial intersecteth the said Ecliptick remaining inclined and oblique upon the same according to the said inclination of Axis And the quantity of the additions importeth as much as the whole diameter of the said Equinoctial the Earths centre being at the same time in the Solstitial points but being out of them it importeth lesse and lesse according as the said centre successively approacheth to the points of the Equinoxes where those additions are lesser than in any other places This is the whole businesse but wrapt up in the
of Tycho made with great expence What Instruments are apt for most exact observation * Italian braces An exquisite observation of the approach and departure of the Sun from the Summer Solstice A place accommodated for the observation of the fixed stars as to what concers the annual motion of the Earth The Copernican Systeme difficult to be understood but easie to be effected Necessary prepositions for the better conceiving of the consequences of the Earths motion A plain Scheme representing the Copernican Hypothesis and its consequences Axiomes commonly admitted by all Philosophers Aristotle taxeth Plato for being too studious of Geometry Peripatetick Philosophers condemn the Study of Geometry and why Four several motions assigned to the Earth The motion of descent belongs not to the terrestrial Globe but to its parts The annual and diurnal motion are compatible in the Earth Every pensil and librated body carryed round in the circumference of a circle acquireth of it self a motion in it self contrary to that An Experiment which sensibly shews that two contrary motions may naturally agree in the same moveable The third motion ascribed to the Earth is rather a resting immoveable An admirable intern vertue of the terrestrial Globe of alwayes beholding the same part of Heaven The terrestrial Globe made of Loade-stone * An eminent Doctor of Physick our Countreyman born at Colchester and famous for this his learned Treatise published about 60 years since at London The Magnetick Philosophy of William Gilbert The Pusillanimity of Popular Wits The Terrestrial Globe composed of sundry matters The interne parts of the terrestrial Globe must of necessity be solid * Or MOULD * Of which with the Latin translatour I must once more professe my self ignorant Our Globe would have been called stone in stead of Earth of that name had been giuen it in the beginning The method of Gilbert in his Philosophy Many properties in the Magnet 〈…〉 The Magnet armed takes up much more Iron than when armed * Or Closet of rarities The first observers and inventers of things ought to be admired The true cause of the multiplication of vertue in the Magnet by means of the arming Of a new effect its necessary that the cause be likewise new It is proved that Iron consists of parts more subtil pure and compact than the magnet A sensible proof of the impurity of the Magnet * The Author hereby meaneth that the stone doth not all consist of magnetick matter but that the whiter specks being weak those other parts of the Loadstone of a more dark constant colour contain all that vertue wherewith bodies are attracted * A common sewing needle Sympathy and Antipathy terms used by Philosophers to give a reason easily of many natural effests A pleasant example declaring the invalidity of some Phylosophical argumentations The several natural motions of the Magnet Aristole grants a compound motion to mixt bodies The motion of mixt bodies ought to be such as may result from the composition of the motions of the simple bodies compounding With two right motions one cannot compose circular motions Philosophers are forced to confesse that the Magnet is compounded of coelestial substances and of elementary The errour of those who call the Magnet a mixt body and the terrestrial Globe a simble body * Ogliopotrida a Spanish dish of many ingredients boild together The Discourses of Peripateticks full of errours and contradictions An improbable effect admired by Gilbertus in the Loadstone The vain argumentation of some to prove the Element of Water to be of a Spherical superficies Nature in sport maketh the ebbing and flowing of the Sea to approve the Earthâ— mobility The tide and mobility of the Earth mutually confirm each other All terrene effects indifferently confirm the motion or rest of the Earth except the ebbing and flowing of the Sea The first general conclusion of the impossibility of the ebbing and flowing the immobility of the terrestrial Globe being granted The knowledge of the effests contributes to the investigation of the causes Three Periods of ebbings and flowings diurnal monethly and annual Varieties that â—appen in the diurâ—â—â— period * A Strair so called * Or Ilva * Or Crets The cause of the ebbing and flowing alledged by a certain modern Philosopher The cause of the ebbing and flowing ascribed to the Moon by a certain Prelate Hieronymus Borrius and other Peripateticks refer it to the temperate heat of the Moon Answers to the vanities alledged as causes of the ebbing and flowing * Or rather smooth The Isles are tokens of the unevennesse of the bottomes of Seas Poetick wits of two kinds Truth hath not so little light as not to be discovered amidst the umbrages of falshoods Aristotle holdeth those effects to be miraculous of which the causes are unknown It is proved impossible that there should naturally be any ebbing and flowing the Earth being immoveable * Palms †Lio is a fair Port in the Venetian Gulph lying N. E. from the City True and natural effects follow without difficulty Two sorts of motions of the containing Vessel may make the contained water to rise and fall The Cavities of the Earth cannot approach or go farther from the centre of the same The progpessive and uneven motion may make the water contained in a Vessel to run to and fro * A Town lying S. E. of Venice The parts of the terrestrial Globe accelerate and regard in their motion Demonstrations how the parts of the terrestriall Globe accelerate and retard The parts of a Circle regularly moved about its own centre move in divers times with contrary motions The mixture of the two motions annnal and diurnal causeth the inequality in the motion of the parts of the terrestrial Globe The most potent and primary cause of the ebbing and flowing Sundry accidents that happen in the ebbings flowings The first accident The Water raised in one end of the Vessel returneth of its self to Aequilibrium In the shorter Vessels the undulations of waters are more frequent The greater profundity maketh the undulations of waters more frequent Water riseth falleth in the extream parts of the Vessel and runneth to and fro in the midst An accident of the Earths motions impossible to be reduced to practice by art Reasons renewed of the particnlar accidents observed in the ebbings and flowings Second causes why in small Seas and in Lakes there are no ebbings and flowings The reason given why the ebbings and flowings for the most part are every six hours The cause why some Seas though very long suffer no ebbing and flowing Ebbings and flowings why greatest in the extremities of Gulphs and least in the middle parts Why in narrow places the course of the waters is more swift than in larger A discussion of 〈…〉 â—abstruce 〈…〉 obseâ—ved 〈…〉 ebbing and â—â—â—wing The cause why in some narrow Channels we see the Sea-waters run alwayes one way * Or current The Hypothesis of the Earths mobility taken in favour of the
whereupon the reflex rayes issue unitedly towards one and the same place but the rest of the pavement which is dry hath its protuberances that is an innumerable variety of inclinations in its smallest particles whereupon the reflections of the light scatter towards all parts but more weakly than if they had gone all united together and therefore the same sheweth almost all alike beheld several wayes but far lesse clear than the moistned brick I conclude therefore that the surface of the Sea beheld from the Moon in like manner as it would appear most equal the Islands and Rocks deducted so it would shew lesse clear than that of the Earth which is montanous and uneven And but that I would not seem as the saying is to harp too much on one string I could tell you that I have observed in the Moon that secondary light which I told you came to her from the reflection of the Terrestrial Globe to be notably more clear two or three dayes before the conjunction than after that is when we see it before break of day in the East than when it is seen at night after Sun-set in the West of which difference the cause is that the Terrestrial Hemisphere which looks towards the Eastern Moon hath little Sea and much Land to wit all Asia whereas when it is in the West it beholds very great Seas that is the whole Atlantick Ocean as far as America An Argument sufficiently probable that the surface of the water appears lesse splendid than that of the Earth SIMPL. So that perhaps you believe those great spots discovered in the face of the Moon to be Seas and the other clearer parts to be Land or some such thing SALV This which you ask me is the beginning of those incongruities which I esteem to be between the Moon and the Earth out of which it is time to dis-ingage our selves for we have stayed too long in the Moon I say therefore that if there were in nature but one way onely to make two superficies illustrated by the Sun to appear one more clear than the other and that this were by the being of the one Earth and the other Water it would be necessary to say that the surface of the Moon were part earthy and part aquatick but because we know many wayes to produce the same effect and others there may be which we know not of therefore I dare not affirm the Moon to consist of one thing more than another It hath been seen already that a silver plate boiled being toucht with the Burnisher becometh of white obscure that the moist part of the Earth shews more obscure than the dry that in the tops of Hills the woody parts appear more gloomy than the naked and barren which hapneth because there falleth very much shadow among the Trees but the open places are illuminated all over by the Sun And this mixtion of shadow hath such operation that in tufted velvet the silk which is cut is of a far darker colour than that which is not cut by means of the shadows diffused betwixt thred and thred and a plain velvet shews much blacker than a Taffata made of the same silk So that if there were in the Moon things which should look like great Woods their aspect might represent unto us the spots which we discover alike difference would be occasioned if there were Seas in her and lastly nothing hindreth but that those spots may really be of an obscurer colour than the rest for thus the snow makes the mountains shew brighter That which is plainly observed in the Moon is that its most obscure parts are all plains with few rises and bancks in them though some there be the rest which is of a brighter colour is all full of rocks mountains hillocks of spherical and other figures and in particular round about the spots are very great ledges of mountains That the spots be plain superficies we have assured proof in that we see how that the term which distinguisheth the part illuminated from the obscure in crossing the spots makes the intersection even but in the clear parts it shews all craggy and shagged But I know not as yet whether this evennesse of superficies may be sufficient of it self alone to make the obscurity appear and I rather think not Besides I account the Moon exceeding different from the Earth for although I imagine to my self that those are not idle and dead Regions yet I affirm not that there are in them motion and life much less that there are bred plants animals or other things like to ours but if such there be they should nevertheless be very different and remote from our imagination And I am induced so to think because in the first place I esteem that the matter of the Lunar Globe consists not of Earth and Water and this alone sufficeth to take away the generations and alterations resembling ours but now supposing that there were in the Moon Water and Earth yet would they not produce plants and animals like to ours and this for two principal reasons The first is that unto our productions there are required so many variable aspects of the Sun that without them they would all miscarry now the habitudes of the Sun towards the Earth are far different from those towards the Moon We as to the diurnal illumination have in the greater part of the Earth every twenty four hours part day and part night which effect in the Moon is monethly and that annual declination and elevation of the Sun in the Zodiack by which it produceth diversity of Seasons and inequality of dayes and nights are finished in the Moon in a moneth and whereas the Sun to us riseth and declineth so much that from the greatest to the least altitude there is a difference of almost 47 degrees for so much is the distance from one to the other Tropick this is in the Moon but ten degrees only or little more namely as much as the greatest Latitudes of the Dragon on each side the Ecliptick Now consider what effect the Sun would have in the torrid Zone should it continually for fifteen dayes together beam forth its Rayes upon it which without all question would destroy plants herbs and living creatures and if it should chance that there were any production it would be of herbs plants and creatures very different from those which are now there Secondly I verily believe that in the Moon there are no rains for if Clouds should gather in any part thereof as they do about the Earth they would thereupon hide from our sight some of those things which we with the Telescope behold in the Moon and in a word would some way or other change its Phaenomenon an effect which I could never by long and diligent observations discover but alwayes beheld it in a even and pure serenity SAGR. To this may be answered either that there might be great
temperate heat able to make the Water swell bid them put fire under a Kettle full of Water and hold their right hand therein till that the Water by reason of the heat do rise but one sole inch and then let them take it out and write off the tumefaction of the Sea Or at least desire them to shew you how the Moon doth to rarefie a certain part of the Waters and not the remainder as for instance these here of Venice and not those of Ancona Naples Genova the truth is Poetick Wits are of two kinds some are ready and apt to invent Fables and others disposed and inclined to believe them SIMP I believe that no man believeth Fables so long as he knows them to be so and of the opinions concerning the causes of ebbing and flowing which are many because I know that of one single effect there is but one single cause that is true and primary I understand very well and am certain that but one alone at the most can be true and for all the rest I am sure that they are fabulous and false and its possible that the true one may not be among those that have been hitherto produced nay I verily believe that it is not for it would be very strange that the truth should have so little light as that it should not be visible amongst the umbrages of so many falshoods But this I shall say with the liberty that is permitted amongst us that the introduction of the Earths motion and the making it the cause of the ebbing and flowing of Tides seemeth to me as yet a conjecture no lesse fabulous than the rest of those that I have heard and if there should not be proposed to me reasons more conformable to natural matters I would without any more ado proceed to believe this to be a supernatural effect and therefore miraculous and unsearchable to the understandings of men as infinite others there are that immediately depend on the Omnipotent hand of God SAGR. You argue very prudently and according to the Doctrine of Aristotle who you know in the beginning of his mechanical questions referreth those things to a Miracle the causes whereof are occult But that the cause of the ebbing and flowing is one of those that are not to be found out I believe you have no greater proof than onely that you see that amongst all those that have hitherto been produced for true causes thereof there is not one wherewith working by what artifice you will we are able to represent such an effect in regard that neither with the light of the Moon nor of the Sun nor with temperate heats nor with different profundities shall one ever artificially make the Water conteined in an immoveable Vessel to run one way or another and to ebbe and flow in one place and not in another But if without any other artifice but with the onely moving of the Vessel I am able punctually to represent all those mutations that are observed in the Sea Water why will you refuse this reason and run to a Miracle SIMP I will run to a Miracle still if you do not with some other natural causes besides that of the motion of the Vessels of the Sea-water disswade me from it for I know that those Vessels move not in regard that all the entire Terrestrial Globe is naturally immoveable SALV But do not you think that the Terrestrial Globe might supernaturally that is by the absolute power of God be made moveable SIMP Who doubts it SALV Then Simplicius seeing that to make the flux and reflux of the Sea it is necessary to introduce a Miracle let us suppose the Earth to move miraculously upon the motion of which the Sea moveth naturally and this effect shall be also the more simple and I may say natural amongst the miraculous operations in that the making a Globe to move round of which kind we see many others to move is lesse difficult than to make an immense masse of water go forwards and backwards in one place more swiftly and in another lesse and to rise and fall in some places more in some lesse and in some not at all and to work all these different effects in one and the same Vessel that containeth it besides that these are several Miracles and that is but one onely And here it may be added that the Miracle of making the water to move is accompanied with another namely the holding of the Earth stedfast against impetuosities of the water able to make it swage sometimes one way and sometimes another if it were not miraculously kept to rights SAGR. God Simplicius let us for the present suspend our judgement about sentencing the new opinion to be vain that Salviatus is about to explicate unto us nor let us so hastily flye out into passion like the scolding overgrown Haggs and as for the Miracle we may as well recurre to it when we have done hearing the Discourses contained within the bounds of natural causes though to speak freely all the Works of nature or rather of God are in my judgement miraculous SALV And I am of the same opinion nor doth my saying that the motion of the Earth is the Natural cause of the ebbing and flowing hinder but that the said motion of the Earth may be miraculous Now reassuming our Argument I apply and once again affirm that it hath been hitherto unknown how it might be that the Waters contained in our Mediterranean Straights should make those motions as we see it doth if so be the said Straight or containing Vessel were immoveable And that which makes the difficulty and rendreth this matter inextricable are the things which I am about to speak of and which are daily observed Therefore lend me your attention We are here in Venice where at this time the Waters are low the Sea calm the Air tranquil suppose it to be young flood and that in the term of five or six hours the water do rise ten hand breadths and more that rise is not made by the first water which was said to be rarefied but it is done by the accession of new Water Water of the same sort with the former of the same brackishness of the same density of the same weight Ships Simplicius float therein as in the former without drawing an hairs breadth more water a Barrel of this second doth not weigh one single grain more or less than such another quantity of the other and retaineth the same coldness without the least alteration And it is in a word Water newly and visibly entred by the Channels and Mouth of the Lio. Consider now how and from whence it came thither Are there happly hereabouts any Gulphs or Whirle-pools in the bottom of the Sea by which the Earth drinketh in and spueth out the Water breathing as it were a great and monstruous Whale But if this be so how comes it that the Water doth not flow in
be moved and not the Earth as namely because the Sun appeareth small and the Earth bigg Again the Motion of the Sun is not discerned by the eye by reason of his seeming tardity but by ratiocination onely in that after some time it varieth not its proximity to such and such Mountains Therefore it is impossible that Reason unless it be first instructed should frame to it self any other apprehension than that the Earth with Heavens Arch placed over it is as it were a great House in which being immoveable the Sun like a Bird flying in the Air passeth in so small a Species out of one Climate into another Which imagination of all Man-kinde being thus gave the first line in the Sacred Leaves In the beginning saith Moses God created the Heaven and the Earth for that these two are most obvious to the eye As if Moses should have said thus to Man This whole Mundane Fabrick which thou seest lucid above and dark and of a vast extent beneath wherein thou hast thy being and with which thou art covered was created by God In another place Man is questioned Whether he can finde out the height of Heaven above or depth of the Earth beneath for that each of them appeareth to men of ordinary capacity to have equally an infinite extent And yet no man that is in his right mind will by these words circumscribe and bound the diligence of Astronomers whether in demonstrating the most contemptible Minuity of the Earth in comparison of Heaven or in searching out Astronomical Distances Since those words speak not of the Rational but real Dimention which to a Humane Body whilst confin'd to the Earth and breathing in the open Air is altogether impossible Read the whole 38. Chapter of Job and compare it with those Points which are disputed in Astronomy and Physiologie If any one do alledge from Psal. 24. That The Earth is founded upon the Seas to the end that he may thence infer some new Principle in Philosophy absurd to hear as That the Earth doth float upon the Waters may it not truly be told him That he ought not to meddle with the Holy Spirit nor to bring him with contempt into the School of Physiologie For the Psalmist in that place means nothing else but that which men fore-know and daily see by experience namely That the Earth being lifted up after the separation of the Waters doth swim between the Grand Oceans and float about the Sea Nor is it strange that the expression should be the same where the Israelites sing That they sate on the River of Babylon that is by the River side or on the Banks of Euphrates and Tygris If any one receive this Reading without scruple why not the other that so in those same Texts which are wont to be alledged against the Motion of the Earth we may in like manner turn our eyes from Natural Philosophy to the scope and intent of Scripture One Generation passeth away saith Ecclesiastes and another Generation cometh But the Earth abideth for ever As if Solomon did here dispute with Astronomers and not rather put men in minde of their Mutability whenas the Earth Mankindes habitation doth alwaies remain the same The Suns Motion doth continually return into what it was at first The Wind is acted in a Circle and returns in the same manner The Rivers flow from their Fountains into the Sea and return again from thence unto their Fountains To conclude The Men of this Age dying others are born in their room the Fable of Life is ever the same there is nothing new under the Sun Here is no reference to any Physical Opinion 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 is Moral of a thing in it self manifest and seen by the eyes of all but little regarded T is that therefore which Solomon doth inculcate For who knows not that the Earth is alwaies the same Who sees not that the Sun dotharise from the East That the Rivers continually run into the Sea That the vicissitudes of the Windes return into their primitive State That some men succeed others But who considereth that the self-same Scene of Life is ever acting by different persons and that nothing is new in humane affairs Therefore Solomon instancing in those things which all men see doth put men in minde of that which many thorowly know but too slightly consider But the 104. Psalm is thought by some to contain a Discourse altogether Physical in regard it onely concerns Natural Philosophy Now God is there said To have laid the Foundations of the Earth that it should not be removed for ever But here also the Psalmist is far from the Speculation of Physical Causes For he doth wholly acquiesce in the Greatnesse of God who did all these things and sings an Hymne to God the Maker of them in which he runneth over the World in order as it appeared to his eyes And if you well consider this Psalme it is a Paraphrase upon the six dayes work of the Creation For as in it the three first dayes were spent in the Separation of Regions the first of Light from the exteriour Darkness the second of the Waters from the Waters by the interposition of the Firmament the third of the Sea from Land when also the Earth was cloathed with Herbage and Plants And the three last dayes were spent in the filling the Regions thus distinguished the fourth of Heaven the fifth of the Seas and Aire the sixth of the Earth So here in this Psalme there are so many distinct parts proportionable to the Analogy of the six dayes Works For in Verse 2. he cloaths and covereth the Creator with Light the first of Creatures and work of the first day as with a Garment The second part beginneth at Verse 3. and treats of the Waters above the Heavens the extent of Heaven and of Meteors which the Psalmist seemeth to intend by the Waters above as namely of Clouds Winds Whirl-winds Lightnings The third part begins at Verse 6. and doth celebrate the Earth as the foundation of all those things which he here considereth For he referreth all things to the Earth and to those Animals which inhabit it for that in the judgment of Sight the two principal parts of the World are Heaven and Earth He therefore here observeth that the Earth after so many Ages hath not faltered tired or decayed when as notwithstanding no man hath yet discovered upon what it is founded He goeth not about to teach men what they do not know but putteth them in minde of what they neglect to wit the Greatnesse and Power of God in creating so huge a Mass so firm and stedfast If an Astronomer should teach that the Earth is placed among the Planets he overthroweth not what the Psalmist here saith nor doth he contradict Common Experience for it is true notwithstanding that the Earth the Structure of God its Architect doth not decay as our Buildings are wont to do
Ferara yet neverthelesse from this particular Doctrine well understood good judgement may be made of other the like cases in general I say then for greater perspecuity and better understanding of the whole That about thirteen miles above Ferara near to Stellata the main of Po branching it self into two parts with one of its Arms it cometh close to Ferara retaining the name of the Po of Ferara and here again it divideth it self into two other branches and that which continueth on the right hand is called the Po of Argenta and of Primaro and that on the left the Po of Volana But for that the bed of the Po of Ferara being heretofore augmented and raised it followeth that it resteth wholly deprived of the Water of the great Po except in the time of its greater swelling for in that case this Po of Ferara being restrained with a Bank near to Bondeno would come also in the overflowings of the main Po to be free from its Waters But the Lords of Ferara are wont at such time as the Po threateneth to break out to cut the bank by which cutting there disgorgeth such a Torrent of Water that it is observed that the main Po in the space of some few hours abateth near a foot and all persons that I have spoken with hitherto moved by this experiment think that it is of great profit and benefit to keep ready this Vent and to make use of it in the time of its fullnesse And indeed the thing considered simply and at the first appearance it seemeth that none can think otherwise the rather for that many examining the matter narrowly measure that body of Water which runneth by the Channel or Bed of the Po of Ferara and make account that the body of the Water of the great Po is diminished the quantity of the body of the Water which runneth by the Po of Ferara But if we well remember what hath been said in the beginning of the Treatise and how much the variety of the velocities of the said Water importeth and the knowledge of them is necessary to conclude the true quantity of the running Water we shall finde it manifest that the benefit of this Vent is far lesse than it is generally thought And mereover we shall finde if I deceive not my self that there follow from thence so many mischiefs that I could greatly incline to believe that it were more to the purpose wholly to stop it up than to maintain it open yet I am not so wedded to my opinion but that I am ready to change my judgement upon strength of better reasons especially of one that shall have first well understood the beginning of this my discourse which I frequently inculcate because it s absolutely impossible without this advertisement to treat of these matters and not commit very great errours I propose therefore to consideration that although it be true that whilst the water of the main Po is at its greatest height the Bank and Dam then cut of the Po of Ferara and the superior waters having a very great fall into the Channel of Ferara they precipitate into the same with great violence and velocity and with the same in the beginning or little lesse they run towards the Po of Volana and of Argenta on the sea coasts yet after the space of some few hours the Po of Ferara being full and the superior Waters not finding so great a diclivity there as they had at the beginning of the cutting they fall not into the same with the former velocity but with far lesse and thereby a great deal lesse Water begins to issue from the great Po and if we diligently compare the velocity at the first cutting with the velocity of the Water after the cutting made and when the Po of Ferara shall be full of Water we shall finde perhaps that to be fifteen or twenty times greater than this and consequently the Water which issues from the great Po that first impetuosity being past shall be onely the fifteenth or twentieth part of that which issued at the beginning and therefore the Waters of the main Po will return in a small time almost to the first height And here I will pray those who rest not wholly satisfied with what hath been said that for the love of truth and the common good they would please to make diligent observation whether in the time of great Floods the said Bank or Dam at Bondeno is cut and that in few hours the main Po diminisheth as hath been said about a foot in its height that they would observe I say whether a day or two being past the Waters of the main Po return almost to their first height for if this should follow it would be very clear that the benefit which resulteth from this diversion or Vent is not so great as is universally presumed I say it is not so great as is presumed because though it be granted for true that the Waters of the main Po abate at the beginning of the Vent yet this benefit happens to be but temporary and for a few hours If the rising of Po and the dangers of breaking forth were of short duration as it ordinarily befalleth in the overflowings of Torrents in such a case the profit of the Vent would be of some esteem But because the swellings of Po continue for thirty or sometimes for forty dayes therefore the gain which results from the Vent proveth to be inconsiderable It remaineth now to consider the notable harms which follow the said Sluice or Vent that so reflection being made and the profit and the detriment compared one may rightly judge and choose that which shall be most convenient The first prejudice therefore which ariseth from this Vent or Sluice is That the Channels of Ferara Primaro and Volana filling with Water all those parts from Bondeno to the Sea side are allarmed and endangered thereby Secondly The Waters of the Po of Primaro having free ingresse into the upper Valleys they fill them to the great damage of the Fields adjacent and obstruct the course of the ordinary Trenches in the same Valleys insomuch that all the care cost and labour about the draining and freeing the upper Valleys from Water would also become vain and ineffectual Thirdly I consider that these Waters of the Po of Ferara being passed downwards towards the Sea at the time that the main Po was in its greater excrescences and heights it is manifest by experience that when the great Po diminisheth then these Waters passed by the Po of Ferara begin to retard in their course and finally come to turn the current upwards towards Stellata resting first iu the intermediate time almost fixed and standing and therefore deposing the muddinesse they fill up the Channel of the River or Current of Ferara Fourthly and lastly There followeth from this same diversion another notable damage and it is like to that which followeth the breaches made by Rivers near to which breaches
by the addition of new Water to that which it dischargeth after the encrease is made Proposition IV. Theor. II. 54 Proportion of a River when highâ—â— to it self when low Coroll I. 55 Q Quantity of Running Waters is never certain if with the Vulgar way of Measuring them their Velocities be not considered 32 Quantities of Waters which are discharged by a River answer in equality to the Velocities and times in which they are discharged Axiome I II III. 38 Quick-Height of a River what it is Definition V. 48 R Reason of the Proverb Take heed of the still Waters Coroll VI. 7 Reasons of Monsignore Corsini against the diversion of Reno into the Po of Volano 105 Reasons of Cardinal Capponi and Monsig Corsini for the turning of Reno into Main Po. 106 Two objections on the contrary and answers to them 104 105 What ought to be the proportion of the Heights of Reno in Reno and of Reno in Po. 110 Regulator what it is Definition IV. 48 Relation of the Waters of Bologna and Ferrara by Monsignore Corsini 100 Reno in the Valleys and its bad effects 100 101 Two wayes to divert it 103 The facility and utility of those wayes Ibid. The difficulties objected 104 Reply to Bartolotti touching the dangers of turning Eiume Morto into Serchio 83 Retardment of the course of a River caused by its Banks Appendix VII 19 Risings made by Flood-Gates but small Appendix XIII 26 Rivers that are shallow swell much upon small showers such as are deep rise but little upon great Floods Corollary III. 6 Rivers the higher they are the swifter Ibid. Rivers the higher they are the lesse they encrease upon Floods 49 Rivers when they are to have equal and when like Velocity Ibid. Rivers in falling into the Sea form a Shelf of Sand called Cavallo 65 Five Rivers to be diverted from the Lake of Venice and the inconveniences that would ensue thereupon 74 75 A River of Quick-height and Velocity in its Regulator being given if the Height be redoubled by new Water it redoubleth also in Velocity Proposition II. Theorem I. 51 Keepeth the proportion of the heights to the Velocities Corollary 52 S Sand and Mud that entereth into the Lake of Venice and the way to examine it 76 Seas agitated and driven by the Winds stop up the Ports 64 65 Sections of a River what they are Definition I. 37 Sections equally swift what they are Definition II. Ibid. Sections of a River being given to conceive others equal to them of different breadth height and Velocity Petition 38 Sections of the same River and their Proportions to their Velocities Coroll I. 42 Sections of a River discharge in any whatsoever place of the said River equal quantities of Water in equal times Proposition I. 39 Sile River what mischiefes it threatneth diverted from the Lake 74 Spirtings of Waters grow bigger the higher they go Coroll XVI 16 Streams of Rivers how they encrease and vary Coroll I. 6 Streams retarded and the effects thereof Coroll IX 8 T Table of the Heights Additions and Quantities of Waters and its use 56 Thrasimenus Vide Lake Time how it s measured in these Operations of the Waters 49 Torrents encrease at the encreasing of a River though they carry no more Water than before Coroll IV. 6 Torrents when they depose and carry away the Sand. Coroll V. 7 Torrents and their effects in a River 6 7 Torrents that fall into the Valleys or into Po of Valano and their mischiefs prevented by the diverting of Reno into Main Po. 100 Tyber and the causes of its inundations Coroll VIII 8 V Valleys of Bologna and Ferrara their inundations and disorders whence they proceed 97 Velocity of the Water shewn by several Examples 3 Its proportion to the Measure 5 Velocities equal what they are 47 Velocities like what they are 47 48 Velocities of Water known how they help us in finding the Lengths 113 A Fable to explain the truth thereof Ibid. Venice Vide Lake Vse of the Regulator in measuring great Rivers Consideration I. 60 W Waters falling why they disgross Coroll XVI 16 Waters how the Length of them is Measured 70 Waters that are imployed to flow Grounds how they are to be distributed 19 53 54 Waters to be carryed in Pipes to serve Aquaducts and Conduits how they are to be Measured 15 116 Way to know the rising of Lakes by Raines 28 Way of the Vulgar to Measure the VVaters of Rivers 68 Wind Gun and Portable Fountain of Vincenzo Vincenti of Urbin 11 Windes contrary retard and make Rivers encrease Coroll VII 8 The END of the TABLE of the Second Part of the First TOME Copernicus reputeth the Earth a Globe like to a Planet Coelestial substances that are in alterable and Elementary that be alterable art necessary in the opinion of Aristotle Aristotle maketh the World perfect because it hath the threefold demension Aristotles demonstrations to prove the dimensions to be three and no more The number three celebrated amongst the Pythagorians Omne Totum Perfectum Or Solid Plato held that humane understanding partook of divinity because it understood numbers The Mystery of Pythagorick numbers fabulous De Papyrio pâ—aetextato Gellius 1. 2. 3. A Geometrical demonstration of the triple dimension In physical proofs â—eâ—metrical exactness is not necessary Parts of the world are two according to Aristotle Coelestial and Elementary contrary to one another Local motion of three kinds right circular mixt Circular and streight motions are simple as proceeding by simple lines Ad medium à 〈◊〉 circa medium The definition of Nature either imperfect or unseasonable produced by Aristotle The Helix about the Cylinder may be said to be a simple line Aristotle accommodates the rules of Architecture to the frame of the World and not the frame to the rules Right motion sometimes simple and sometimes mixt according to Arist. The circular line perfect according to Aristotle and but the right imperfect and why The world is supposed by the Author to be perfectly ordinate Streight motion impossible in the world exactly ordinate Right motion nature infinite Motion by a right line naturally impossible Nature attempts not things impossible to be effected Right motion might perhaps be in thâ— first Chaos Right motion is commodious to range in order things out of order Mundane bodies moved in the beginning in a right line and afterwards circularly according to Plato * Thus doth he coverâ—ly and modestly stile himselfe throughout this work A moveable being in a state of rest shall not move unless it have an inclination to some particular place The moveable accelerates its motion going towards the place whither it hath an inclination The moveable passing from rest goeth thorow all the degrees of tardity Rest the infinite degree of tardity The moveable doth not accelerate save only as it approacheth nearer to us term Nature to introduce in the moveable a certain degree of velocity made it move in a right line Vniform
without what and how great would its motion be SIMPL. The motion would go continually decreasing and retarding as being contrary to nature and would be longer or shorter according to the greater or less impulse and according to the greater or less acclivity SALV It seems then that hitherto you have explained to me the accidents of a moveable upon two different Planes and that in the inclining plane the grave moveable doth spontaneously descend and goeth continually accelerating and that to retain it in rest force must be used therein but that on the ascending plane there is required a force to thrust it forward and also to stay it in rest and that the motion impressed goeth continually diminishing till that in the end it cometh to nothing You say yet farther that in both the one and the other case there do arise differences from the planes having a greater or less declivity or acclivity so that the greater inclination is attended with the greater velocity and contrariwise upon the ascending plane the same moveable thrown with the same force moveth a greater distance by how much the elevation is less Now tell me what would befall the same moveable upon a superficies that had neither acclivity nor declivity SIMPL. Here you must give me a little time to consider of an answer There being no declivity there can be no natural inclination to motion and there being no acclivity there can be no resistance to being moved so that there would arise an indifference between propension and resistance of motion therefore methinks it ought naturally to stand still But I had forgot my self it was but even now that Sagredus gave me to understand that it would so do SALV So I think provided one did lay it down gently but if it had an impetus given it towards any part what would follow SIMP There would follow that it should move towards that part SALV But with what kind of motion with the continually accelerated as in declining planes or with the successively retarded as in those ascending SIMP I cannot tell how to discover any cause of acceleration or retardation there being no declivity or acclivity SALV Well but if there be no cause of retardation much less ought there to be any cause of rest How long therefore would you have the moveable to move SIMP As long as that superficies neither inclined nor declined shall last SALV Therefore if such a space were interminate the motion upon the same would likewise have no termination that is would be perpetual SIMP I think so if so be the moveable be of a matter durable SALV That hath been already supposed when it was said that all external and accidental impediments were removed and the brittlenesse of the moveable in this our case is one of those impediments accidental Tell me now what do you think is the cause that that same Ball moveth spontaneously upon the inclining plane and not without violence upon the erected SIMP Because the inclination of grave bodies is to move towards the centre of the Earth and onely by violence upwards towards the circumference and the inclining superficies is that which acquireth vicinity to the centre and the ascending one remotenesse SALV Therefore a superficies which should be neither declining nor ascending ought in all its parts to be equally distant from the centre But is there any such superficies in the World SIMP There is no want thereof Such is our Terrestrial Globe if it were more even and not as it is rough and montainous but you have that of the Water at such time as it is calm and still SALV Then a ship which moveth in a calm at Sea is one of those moveables which run along one of those superficies that are neither declining nor ascending and therefore disposed in case all obstacles external and accidental were removed to move with the impulse once imparted incessantly and uniformly SIMPL. It should seem to be so SALV And that stone which is on the round top doth not it move as being together with the ship carried about by the circumference of a Circle about the Centre and therefore consequently by a motion in it indelible if all extern obstacles be removed And is not this motion as swift as that of the ship SIMPL. Hitherto all is well But what followeth SALV Then in good time recant I pray you that your last conclusion if you are satisfied with the truth of all the premises SIMPL. By my last conclusion you mean That that same stone moving with a motion indelibly impressed upon it is not to leave nay rather is to follow the ship and in the end to light in the self same place where it falleth when the ship lyeth still and so I also grant it would do in case there were no outward impediments that might disturb the stones motion after its being let go the which impediments are two the one is the moveables inability to break through the air with its meer impetus onely it being deprived of that of the strength of Oars of which it had been partaker as part of the ship at the time that it was upon the Mast the other is the new motion of descent which also must needs be an hinderance of that other progressive motion SALV As to the impediment of the Air I do not deny it you and if the thing falling were a light matter as a feather or a lock of wool the retardation would be very great but in an heavy stone is very exceeding small And you your self but even now did say that the force of the most impetuous wind sufficeth not to stir a great stone from its place now do but consider what the calmer air is able to do being encountred by a stone no more swift than the whole ship Neverthelesse as I said before I do allow you this small effect that may depend upon such an impediment like as I know that you will grant to me that if the air should move with the same velocity that the ship and stone hath then the impediment would be nothing at all As to the other of the additional motion downwards in the first place it is manifest that these two I mean the circular about the centre and the streight towards the centre are not contraries or destructive to one another or incompatible Because that as to the moveable it hath no repugnance at all to such motions for you your self have already confest the repugnance to be against the motion which removeth from the centre and the inclination to be towards the motion which approacheth to the centre Whence it doth of necessity follow that the moveable hath neither repugnance nor propension to the motion which neither approacheth nor goeth from the centre nor consequently is there any cause for the diminishing in it the faculty impressed And forasmuch as the moving cause is not one alone which it hath attained by the new operation of retardation but that they are two distinct
a minutes interval the same water to begin to return back again and the tide from ebbing to become young flood without standing still a moment an effect that as long as I have dwelt in Venice I never took notice of before SAGR. It is very much that you should be left thus on ground amongst small Channels in which rivolets as having very little declivity the rising or falling of the main sea the thickness onely of a paper is sufficient to make the water to ebbe and flow for good long spaces of time like as in some creeks of the Sea its flowing four or six yards onely maketh the water to overflow the adjacent Marshes for some hundreds and thousands of acres SIMP This I know very well but I should have thought that between the ultimate terme of ebbing and the first beginnng to flow there should have interposed some considerable interval of rest SAGR. This will appear unto you if you cast your eye upon the bank or piles where these mutations are made perpendicularly but not that there is any real time of cessation SIMP I did think that because these two motions were contrary there ought to be in the midst between them some kind of rest conformable to the Doctrine of Aristotle which demonstrates that in puncto regressus mediat quies SAGR. I very well remember this place but I bear in minde also that when I read Philosophy I was not thorowly satisfied with Aristotles demonstration but that I had many experiments on the contrary which I could still rehearse unto you but I am unwilling to sally out into any other digressions we being met here to discourse of the proposed mattes if it be possible without these excursions wherewith we have interrupted our disputes in those dayes that are past SIMP And yet we may with convenience if not-interrupt them at least prolong them very much for returning yesterday home I set my self to read the Tractate of Conclusions where I find Demonstrations against this annual motion ascribed to the Earth very solid and because I would not trust my memory with the punctual relation of them I have brought back the Book along with me SAGR. You have done very well but if we would re-assume our Disputations according to yesterdayes appointment it is requisite that we first hear what account Salviatus hath to give us of the Book De stellis novis and then without interruption we may proceed to the Annual motion Now what say you Salviatus touching those stars Are they really pull'd down from Heaven to these lower regions by vertue of that Authours calculations whom Simplicius mentioneth SALV I set my self last night to peruse his proceedings and I have this morning had another view of him to see whether that which he seemed over night to affirm were really his sense or my dreams and phantastical nocturnal imaginations and in the close found to my great grief that those things were really written and printed which for the reputation-sake of this Philosopher I was unwilling to believe It is in my judgment impossible but that he should perceive the vanity of his undertaking aswell because it is too apert as because I remember that I have heard him mentioned with applause by the Academick our Friend it seemeth to me also to be a thing very unlikely that in complacency to others he should be induced to set so low a value upon his reputation as to give consent to the publication of a work for which he could expect no other than the censure of the Learned SAGR. Yea but you know that those will be much fewer than one for an hundred compared to those that shall celebrate and extoll him above the greatest wits that are or ever have been in the world He is one that hath mentioned the Peripatetick inalterability of Heaven against a troop of Astronomers and that to their greater disgrace hath foiled them at their own weapons and what do you think four or five in a Countrey that discern his triflings can do against the innumerable multitude that not being able to discover or comprehend them suffer themselves to be taken with words and so much more applaud him by how much the lesse they understand him You may adde also that those few who understand scorn to give an answer to papers so trivial and unconcludent and that upon very good reasons because to the intelligent there is no need thereof and to those that do not understand it is but labour lost SALV The most deserved punishment of their demerits would certainly be silence if there were not other reasons for which it is haply no lesse than necessary to resent their timerity one of which is that we Italians thereby incur the censure of Illiterates and attract the laughter of Forreigners and especially to such who are separated from our Religion and I could shew you many of those of no small eminency who scoff at our Academick and the many Mathematicians that are in Italic for suffering the follies of such a Fabler against Astronomers to come into the light and to be openly maintained without contradiction but this also might be dispensed with in respect of the other greater occasions of laughter wherewith we may confront them depending on the dissimulation of the intelligent touching the follies of these opponents of the Doctrines that they well enough understand SAGR. I desire not a greater proof of those mens petulancy and the infelicity of a Copernican subject to be opposed by such as understand not so much as the very first positions upon which he undertakes the quarrel SALV You will be no lesse astonished at their method in confuting the Astronomers who affirm the new Stars to be superiour to the Orbs of the Planets and peradventure in the Firmament it self SAGR. But how could you in so short a time examine all this Book which is so great a Volume and must needs contain very many demonstrations SALV I have confined my self to these his first confutations in which with twelve demonstrations founded upon the observations of twelve Astronomers who all held that the Star Anno 1572. which appeared in Cassiopeia was in the Firmament he proveth it on the contrary to be beneath the Moon conferring two by two the meridian altitudes proceeding in the method that you shall understand by and by And because I think that in the examination of this his first progression I have discovered in this Authour a great unlikelihood of his ability to conclude any thing against the Astronomers in favour of the Peripatetick Philosophers and that their opinion is more and more concludently confirmed I could not apply my self with the like patience in examining his other methods but have given a very slight glance upon them and am certain that the defect that is in these first impugnations is likewise in the rest And as you shall see by experience very few words will suffice to confute this
so between them both compose this our Globe writeth that the seeing the small * particles of water shape themselves into rotundity as in the drops and in the dew daily apparent upon the leaves of several herbs is a strong argument and because according to the trite Axiome there is the same reason for the whole as for the parts the parts affecting that same figure it is necessary that the same is proper to the whole Element and truth is methinks it is a great oversight that these men should not perceive so apparent a vanity and consider that if their argument had run right it would have followed that not only the small drops but that any whatsoever greater quantity of water separated from the whole Element should be reduced into a Globe Which is not seen to happen though indeed the Senses may see and the Understanding perceive that the Element of Water loving to form it self into a Spherical Figure about the common centre of gravity to which all grave bodies tend that is the centre of the Terrestrial Globe it therein is followed by all its parts according to the Axiome so that all the surfaces of Seas Lakes Pools and in a word of all the parts of Waters conteined in vessels distend themselves into a Spherical Figure but that Figure is an arch of that Sphere that hath for its centre the centre of the Terrestrial Globe and do not make particular Spheres of themselves SALV The errour indeed is childish and if it had been onely the single mistake of Sacrobosco I would easily have allowed him in it but to pardon it also to his Commentators and to other famous men and even to Ptolomy himselfe this I cannot do without blushing for their reputation But it is high time to take leave it now being very late and we being to meet again to morrow at the usual hour to bring all the foregoing Discourses to a final conclusion Place this Plate at the end of the third Dialogue GALILAEUS Gailaeus Lyncaeus HIS SYSTEME OF THE WORLD The Fourth Dialogue INTERLOCVTORS SALVIATUS SAGREDUS SIMPLICIUS SAGR. I know not whether your return to our accustomed conferences hath really been later than usual or whether the desire of hearing the thoughts of Salviatus touching a matter so curious hath made me think it so But I have tarried a long hour at this window expecting every moment when the Gondola would appear that I sent to fetch you SALV I verily believe that your imagination more than our tarriance hath prolonged the time and to make no longer demurre it would be well if without interposing more words we came to the matter it self and did shew that nature hath permitted whether the business in rei veritate be so or else to play and sport with our Fancies hath I say hath permitted that the motions for every other respect except to resolve the ebbing and flowing of the Sea assigned long since to the earth should be found now at last to answer exactly to the cause thereof and as it were with mutual a emulation the said ebbing and flowing to appear in confirmation of the Terrestrial motion the judices whereof have hitherto been taken from the coelestial Phaenomena in regard that of those things that happen on Earth not any one was of force to prove one opinion more than another as we already have at large proved by shewing that all the terrene occurrences upon which the stability of the Earth and mobility of the Sun and Firmament is commonly inferred are to seem to us performed in the same manner though we supposed the mobility of the Earth and the immobility of them The Element of Water onely as being most vast and which is not annexed and concatenated to the Terrestrial Globe as all its other solid parts are yea rather which by reason of its fluidity remaineth apart sui juris and free is to be ranked amongst those sublunary things from which we may collect some hinte and intimation of what the Earth doth in relation to motion and rest After I had many and many a time examined with my self the effects and accidents partly seen and partly understood from others that are to be observed in the motions of waters and moreover read and heard the great vanities produced by many as the causes of those accidents I have been induced upon no slight reasons to omit these two conclusions having made withal the necessary presupposals that in case the terrestrial Globe be immoveable the flux and reflux of the Sea cannot be natural and that in case those motions be conferred upon the said Globe which have been long since assigned to it it is necessary that the Sea be subject to ebbing and flowing according to all that which we observe to happen in the same SAGR. The Proposition is very considerable as well for it self as for what followeth upon the same by way of consequence so that I shall the more intensly hearken to the explanation and confirmation of it SALV Because in natural questions of which number this which we have in hand is one the knowledge of the effects is a means to guide us to the investigation and discovery of the causes and without which we should walk in the dark nay with more uncertainty for that we know not whither we would go whereas the blind at least know where they desire to arrive therefore first of all it is necessary to know the effects whereof we enquire the causes of which effects you Sagredus ought more abundantly and more certainly to be informed than I am as one that besides your being born and having for a long time dwelt in Venice where the Tides are very notable for their greatnesse have also sailed into Syria and as an ingenuous and apprehensive wit must needs have made many Observations upon this subject whereas I that could onely for a time and that very short observe what happened in these extream parts of the Adriatick Gulph and in our Seas below about the Tyrrhene shores must needs take many things upon the relation of others who for the most part not very well agreeing and consequently being very uncertain contribute more of confusion than confirmation to our speculations Neverthelesse from those that we are sure of and which are the principal I think I am able to attain to the true and primary causes not that I pretend to be able to produce all the proper and adequate reasons of those effects that are new unto me and which consequently I could never have thought upon And that which I have to say I propose only as a key that openeth the door to a path never yet trodden by any in certain hope that some wits more speculative than mine will make a further progresse herin and penetrate much farther than I shall have done in this my first Discovery And although that in other Seas remote from us there may â—appen several accidents which
the space of six hours in Ancona in * Ragusa in Corfu where the Tide is very small and happly unobservable Who will invent a way to pour new Water into an immoveable Vessel and to make that it rise onely in one determinate part of it and in other places not Will you say that this new Water is borrowed from the Ocean being brought in by the Straight of Gibraltar This will not remove the doubt aforesaid but will beget a greater And first tell me what ought to be the current of that Water that entering at the Straights mouth is carried in six hours to the remotest Creeks of the Mediterrane at a distance of two or three thousand Miles and that returneth the same space again in a like time at its going back What would Ships do that lye out at Sea What would become of those that should be in the Straights-mough in a continual precipice of a vast accumulation of Waters that entering in at a Channel but eight Miles broad is to give admittance to so much Water as in six hours over-floweth a tract of many hundred Miles broad thousands in length What Tygre what Falcon runneth or flyeth with so much swiftness With the swiftness I say of above 400 Miles an hour The currents run nor can it be denied the long-wayes of the Gulph but so slowly as that a Boat with Oars will out-go them though indeed not without defalking for their wanderings Moreover if this Water come in at the Straight the other doubt yet remaineth namely how it cometh to flow here so high in a place so remote without first rising a like or greater height in the parts more adjacent In a word I cannot think that either obstinacy or sharpness of wit can ever find an answer to these Objections nor consequently to maintain the stability of the Earth against them keeping within the bounds of Nature SAGR. I have all the while perfectly apprehended you in this and I stand greedily attending to hear in what manner these wonders may occur without obstruction from the motion already assigned to the Earth SALV These effects being to ensue in consequence of the motions that naturally agree with the Earth it is necessary that they not onely meet with no impediment or obstacle but that they do follow easily not onely that they follow with facility but with necessity so as that it is impossible that it should succeed otherwise for such is the property condition of things natural true Having therefore shewen the impossibility of rendring a reason of the motions discerned in the Waters at the same time to maintain the immobility of the vessel that containeth them we may proceed to enquire whether the mobility of the Container may produce the required effect in the manner that it is observed to evene Two kinds of motions may be conferred upon a Vessel whereby the Water therein contained may acquire a faculty of fluctuating in it one while towards one side and another while towards another and there one while to ebbe and another while to flow The first is when first one and then another of those sides is declined for then the Water running towards the inclining side will alternately be higher and lower sometimes on one side and sometimes on another But because that this rising and abating is no other than a recession and accession to the centre of the Earth such a motion cannot be ascribed to the Cavities of the said Earth that are the Vessels which contain the Waters the parts of which Vessel cannot by any whatsoever motion assigned to the Earth be made to approach or recede from the centre of the same The other sort of motion is when the Vessel moveth without inclining in the least with a progressive motion not uniform but that changeth velocity by sometimes accellerating and other times retarding from which disparity it would follow that the VVater contained in the Vessel its true but not fixed fast to it as its other solid parts but by reason of its fluidity as if it were separated and at liberty and not obliged to follow all the mutations of its Container in the retardation of the Vessel it keeping part of the impetus before conceived would run towards the the preceding part whereupon it would of necessity come to rise and on the contrary if new velocity should be added to the Vessel with retaining parts of its tardity staying somewhat behind before it could habituate it self to the new impetus it would hang back towards the following part where it would come to rise something The which effects we may plainly declare and make out to the Sense by the example of one of those same Barks yonder which continually come from Lizza-Fusina laden with fresh water for the service of the City Let us therefore fancy one of those Barks to come from thence with moderate velocity along the Lake carrying the water gently of which it is full and then either by running a ground or by some other impediment that it shall meet with let it be notably retarded The water therein contained shall not by that means lose as the Bark doth its pre-conceived impetus but retaining the same shall run forwards towards the prow where it shall rise notably falling as much a stern But if on the contrary the said Bark in the midst of its smooth course shall have a new velocity with notable augmentation added to it the water contained before it can habituate it self thereto continuing in its tardity shall stay behinde namely a stern where of consequence it shall mount and abate for the same at the prow This effect is undoubted and manifest and may hourly be experimented in which I desire that for the present three particulars may be noted The first is that to make the water to rise on one side of the vessel there is no need of new water nor that it run thither forsaking the other side The second is that the water in the middle doth not rise or fall notably unlesse the course of the Bark were not before that very swift and the shock or other arrest that held it exceeding strong and sudden in which case its possible that not only all the water might run forwards but that the greater part thereof might issue forth of the Bark and the same also would ensue whilst that being under sail in a smooth course a most violent impetus should upon an instant overtake it But when to its calme motion there is added a moderate retardation or incitation the middle parts as I said unobservedly rise and fall and the other parts according as they are neerer to the middle rise the lesse and the more remote more The third is that whereas the parts about the midst do make little alteration in rising and falling in respect of the waters of the sides on the contrary they run forwards and backwards very much in comparison of
in those that distend themselves for a great length from VVest to East namely according to the course of the motions of the Terrestrial Globe and as it is in a certain manner unthought of and without a president among the motions possible to be made by us so it is not hard for me to believe that effects may be derived from the same which are not to be imitated by our artificial experiments SALV These things being declared it is time that we proceed to examine the particular accidents which together with their diversities are observed by experience in the ebbing and flowing of the waters And first we need not think it hard to guesse whence it happeneth that in Lakes Pooles and also in the lesser Seas there is no notable flux and reflux the which hath two very solid reasons The one is that by reason of the shortnesse of the Vessel in its acquiring in several hours of the day several degrees of velocity they are with very little difference acquired by all its parts for as well the precedent as the subsequent that is to say both the Eastern and VVestern parts do accelerate and retard almost in the same manner and withal making that alteration by little and little and not by giving the motion of the conteining Vessel a sudden check and retardment or a sudden and great impulse or acceleration both it and all its parts come to be gently and equally impressed with the same degrees of velocity from which uniformity it followeth that also the conteined water with but small resistance and opposition receiveth the same impressions and by consequence doth give but very obscure signes of its rising or falling or of its running towards one part or another The which effect is likewise manifestly to be seen in the little artificial Vessels wherein the contained water doth receive the self same impressions of velocity when ever the acceleration and retardation is made by gentle and uniform proportion But in the Straights and Bays that for a great length distend themselves from East to West the acceleration and retardation is more notable and more uneven for that one of its extreams shall be much retarded in motion and the other shall at the same time move very swiftly The reciprocal libration or levelling of the water proceeding from the impetus that it had conceived from the motion of its container The which libration as hath been noted hath its undulations very frequent in small Vessels from whence ensues that though there do reside in the Terrestrial motions the cause of conferring on the waters a motion onely from twelve hours to twelve hours for that the motion of the conteining Vessels do extreamly accelerate and extreamly retard but once every day and no more yet neverthelesse this same second cause depending on the gravity of the water which striveth to reduce it self to equilibration and that according to the shortnesse of the Vessel hath its reciprocations of one two three or more hours this intermixing with the first which also it self in small Vessels is very little it becommeth upon the whole altogether insensible For the primary cause which hath the periods of twelve hours having not made and end of imprinting the precedent commotion it is overtaken and opposed by the other second dependant on the waters own weight which according to the brevity and profundity of the Vessel hath the time of its undulations of one two three four or more hours and this contending with the other former one disturbeth and removeth it not permitting it to come to the height no nor to the half of its motion and by this contestation the evidence of the ebbing and flowing is wholly annihilated or at least very much obscured I passe by the continual alteration of the air which disquieting the water permits us not to come to a certainty whether any though but small encrease or abatement of half an inch or losse do reside in the Straights or receptacles of water not above a degree or two in length I come in the second place to resolve the question why there not residing any vertue in the primary principle of commoving the waters save onely every twelve hours that is to say once by the greatest velocity and once by the greatest tardity of motion the ebbings and flowings should yet neverthelesse appear to be every six hours To which is answered that this determination cannot any wayes be taken from the primary cause onely but there is a necessity of introducing the secondary causes as namely the greater or lesse length of the Vessels and the greater or lesse depth of the waters in them conteined Which causes although they have not any operation in the motions of the waters those operations belonging to the sole primary cause without which no ebbing or flowing would happen yet neverthelesse they have a principal share in determining the times or periods of the reciprocations and herein their influence is so powerful that the primary cause must of force give way unto them The period of six hours therefore is no more proper or natural than those of other intervals of times though indeed its the most observed as agreeing with our Mediterrane which was the onely Sea that for many Ages was navigated though neither is that period observed in all its parts for that in some more angust places such as are the Hellespont and the Aegean Sea the periods are much shorter and also very divers amongst themselves for which diversities and their causes incomprehensible to Aristotle some say that after he had a long time observed it upon some cliffes of Negropont being brought to desperation he threw himself into the adjoyning Euripus and voluntarily drowned himself In the third place we have the reason ready at hand whence it commeth to passe that some Seas although very long as is the Red Sea are almost altogether exempt from Tides which happeneth because their length extendeth not from East to West but rather transversly from the Southeast to the Northwest but the motions of the Earth going from West to East the impulses of the water by that means alwayes happen to fall in the Meridians and do not move from parallel to parallel insomuch that in the Seas that extend themselves athwart towards the Poles and that the contrary way are narrow there is no cause of ebbing and flowing save onely by the participation of another Sea wherewith it hath communication that is subject to great commotions In the fourth place we shall very easily find out the reason why the fluxes and refluxes are greatest as to the waters rising and falling in the utmost extremities of Gulphs and least in the intermediate parts as daily experience sheweth here in Venice lying in the farther end of the Adriatick Sea where that difference commonly amounts to five or six feet but in the places of the Mediterrane far distant from the extreams that mutation is very small as in
the Isles of Corsica and Sardinnia and in the Strands of Rome and Ligorne where it exceeds not half a foot we shall understand also why on the contrary where the risings and fallings are small the courses and recourses are great I say it is an easie thing to understand the causes of these accidents seeing that we meet with many manifest occurrences of the same nature in every kind of Vessel by us artificially composed in which the same effects are observed naturally to follow upon our moving it unevenly that is one while faster and another while flower Moreover considering in the fifth place that the same quantity of Water being moved though but gently in a spatious Channel comming afterwards to go through a narrow passage will of necessity run with great violence we shall not finde it hard to comprehend the cause of the great Currents that are made in the narrow Channel that separateth Calabria from Sicilia for that all the Waters that by the spaciousnesse of the Isle and by the Ionick Gulph happens to be pent in the Eastern part of the Sea though it do in that by reason of its largeness gently descend towards the West yet neverthelesse in that it is pent up in the Bosphorus it floweth with great violence between Scilla and Caribdis and maketh a great agitation Like to which and much greater is said to be betwixt Africa and the great Isle of St. Lorenzo where the Waters of the two vast Seas Indian and Ethiopick that lie round it must needs be straightned into a lesse Channel between the said Isle and the Ethiopian Coast. And the Currents must needs be very great in the Straights of Megallanes which joyne together the vast Oceans of Ethiopia and Del Zur called also the Pacifick Sea It follows now in the sixth place that to render a reason of some more abstruse and incredible accidents which are observed upon this occasion we make a considerable reflection upon the two principal causes of ebbings and flowings afterwards compounding and mixing them together The first and simplest of which is as hath often been said the determinate acceleration and retardation of the parts of the Earth from whence the Waters have a determinate period put to their decursions towards the East and return towards the West in the time of twenty four hours The other is that which dependeth on the proper gravity of the Water which being once commoved by the primary cause seeketh in the next place to reduce it self to Aequilibrium with iterated reciprocations which are not determined by one sole and prefixed time but have as many varieties of times as are the different lengths and profundities of the receptacles and Straights of Seas and by what dependeth on this second principle they would ebbe and flow some in one hour others in two in four in six in eight in ten c. Now if we begin to put together the first cause which hath its set Period from twelve hours to twelve hours with some one of the secondary that hath its Period verb. grat from five hours to five hours it would come to passe that at sometimes the primary cause and secondary would accord to make impulses both one the same way and in this concurrency and as one may call it unanimous conspiration the flowings shall be great At other times it happening that the primary impulse doth in a certain manner oppose that which the secondary Period would make and in this contest one of the Principles being taken away that which the other would give will weaken the commotion of the Waters and the Sea will return to a very tranquil State and almost immoveable And at other times according as the two aforesaid Principles shall neither altogether contest nor altogether concur there shall be other kinds of alterations made in the increase and diminution of the ebbing and flowing It may likewise fall out that two Seas considerably great and which communicate by some narrow Channel may chance to have by reason of the mixtion of the two Principles of motion one cause to flow at the time that the other hath cause to move a contrary way in which case in the Channel whereby they disimbogue themselves into each other there do extraordinary conturbations insue with opposite and vortick motions and most dangerous boilings and breakings as frequent relations and experiences do assure us From such like discordant motions dependent not onely on the different positions and longitudes but very much also upon the different profundities of the Seas which have the said intercourse there do happen at sometimes different commotions in the Waters irregular and that can be reduced to no rules of observation the reasons of which have much troubled and alwayes do trouble Mariners for that they meet with them without seeing either impulse of winds or other eminent aereal alteration that might occasion the same of which disturbance of the Air we ought to make great account in other accidents and to take it for a third and accidental cause able to alter very much the observation of the effects depending on the secondary and more essential causes And it is not to be doubted but that impetuous windes continuing to blow for example from the East they shall retein the Waters and prohibit the reflux or ebbing whereupon the second and third reply of the flux or tide overtaking the former at the hours prefixed they will swell very high and being thus born up for some dayes by the strength of the Winds they shall rise more than usual making extraordinary inundations We ought also and this shall serve for a seventh Probleme to take notice of another cause of motion dependant on the great abundance of the Waters of great Rivers that discharge themselves into Seas of no great capacity whereupon in the Straits or Bosphori that communicate with those Seas the Waters are seen to run always one way as it happeneth in the Thracian Bosphorus below Constantinople where the water alwayes runneth from the black-Black-Sea towards the Propontis For in the said Black-Sea by reason of its shortnesse the principal causes of ebbing and flowing are but of small force But on the contrary very great Rivers falling into the same those huge defluxions of water being to passe and disgorge themselves by the the straight the course is there very notable and alwayes towards the South Where moreover we ought to take notice that the said Straight or Channel albeit very narrow is not subject to perturbations as the Straight of Scilla and Carybdis for that that hath the Black-Sea above towards the North and the Propontis the Aegean and the Mediterranean Seas joyned unto it though by a long tract towards the South but now as we have observed the Seas though of never so great length lying North and South are not much subject to ebbings and flowings but because the Sicilian Straight is situate between the parts of the Mediterrane distended
for a long tract or distance from West to East that is according to the course of the fluxes and refluxes therefore in this the agitations are very great and would be much more violent between Hercules Pillars in case the Straight of Gibraltar did open lesse and those of the Straight of Magellanes are reported to be extraordinary violent This is what for the present cometh into my mind to say unto you about the causes of this first period diurnal of the Tide and its various accidents touching which if you have any thing to offer you may let us hear it that so we may afterwards proceed to the other two periods monethly and annual SIMP In my opinion it cannot be denied but that your discourse carrieth with it much of probability arguing as we say ex suppositione namely granting that the Earth moveth with the two motions assigned it by Copernicus but if that motion be disproved all that you have said is vain and insignificant and for the disproval of that Hypothesis it is very manifestly hinted by your Discourse it self You with the supposition of the two Terrestrial motions give a reason of the ebbing and flowing and then again arguing circularly from the ebbing and flowing draw the reason and confirmation of those very motions and so proceeding to a more specious Discourse you say that the Water as being a fluid body and not tenaciously annexed to the Earth is not constrained punctually to obey every of its motions from which you afterwards infer its ebbing and flowing Now I according to your own method argue the quite contrary and say the Air is much more tenuous and fluid than the Water and lesse annexed to the Earths superficies to which the Water if it be for nothing else yet by reason of its gravity that presseth down upon the same more than the light Air adhereth therefore the Air is much obliged to follow the motions of the Earth and therefore were it so that the Earth did move in that manner we the inhabitants of it and carried round with like velocity by it ought perpetually to feel a Winde from the East that beateth upon us with intolerable force And that so it ought to fall out quotidian experience assureth us for if with onely riding post at the speed of eight or ten miles an hour in the tranquil Air the incountering of it with our face seemeth to us a Winde that doth not lightly blow upon us what should we expect from our rapid course of 800. or a thousand miles an hour against the Air that is free from that motion And yet notwithstanding we cannot perceive any thing of that nature SALV To this objection that hath much of likelihood in it I reply that its true the Air is of greater tenuity and levity and by reason of its levity lesse adherent to the Earth than Water so much more grave and bulky but yet the consequence is false that you infer from these qualities namely that upon account of that its levity tenuity and lesse adherence to the Earth it should be more exempt than the Water from following the Terrestrial Motions so as that to us who absolutely pertake of of them the said exemption should be sensible and manifest nay it happeneth quite contrary for if you well remember the cause of the ebbing and flowing of the Water assigned by us consisteth in the Waters not following the unevennesse of the motion of its Vessel but retaining the impetus conceived before without diminishing or increasing it according to the precise rate of its diminishing or increasing in its Vessel Because therefore that in the conservation and retention of the impetus before conceived the disobedience to a new augmentation or diminution of motion consisteth that moveable that shall be most apt for such a retention shall be also most commodious to demonstrate the effect that followeth in consequence of that retention Now how much the Water is disposed to maintain such a conceived agitation though the causes cease that impress the same the experience of the Seas extreamly disturbed by impetuous Winds sheweth us the Billows of which though the Air be grown calm and the Wind laid for a long time after continue in motion As the Sacred Poet pleasantly sings Qual l'alto Egeo c. And that long continuing rough after a storm dependeth on the gravity of the water For as I have elsewhere said light bodies are much easier to be moved than the more grave but yet are so much the less apt to conserve the motion imparted when once the moving cause ceaseth Whence it comes that the Aire as being of it self very light and thin is easily mov'd by any very small force yet it is withall very unable to hold on its motion the Mover once ceasing Therefore as to the Aire which environs the Terrestrial Globe I would fay that by reason of its adherence it is no lesse carried about therewith then the Water and especially that part which is contained in its vessels which vessels are the valleys enclosed with Mountains And we may with much more reason affirm that this same part of the Air is carried round and born forwards by the rugged parts of the Earth than that the higher is whirl'd about by the motion of the Heavens as ye Peripateticks maintain What hath been hitherto spoken seems to me a sufficient answer to the allegation of Simplitius yet nevertheless with a new instance and solution founded upon an admirable experiment I will superabundantly satisfie him and confirm to Sagredus the mobility of the Earth I have told you that the Air and in particular that part of it which ascendeth not above the tops of the highest Mountains is carried round by the uneven parts of the Earths surface from whence it should seem that it must of consequence come to passe that in case the superficies of the Earth were not uneven but smooth and plain no cause would remain for drawing the Air along with it or at least for revolving it with so much uniformity Now the surface of this our Globe is not all craggy and rugged but there are exceeding great tracts very even to wit the surfaces of very vast Seas which being also far remote from the continuate ledges of Mountains which environ it seem to have no faculty of carrying the super-ambient Air along therewith and not carrying it about we may perceive what will of consequence ensue in those places SIMP I was about to propose the very same difficulty which I think is of great validity SALV You say very well Simplicius for from the not finding in the Air that which of consequence would follow did this our Globe move round you argue its immoveablenesse But in case that this which you think ought of necessary consequence to be found be indeed by experience proved to be so will you accept it for a sufficient testimony and an argument for the mobility of
scarce kist her Maid yet nevertheless to give you my sudden thoughts I shall tell you That of those effects by you recounted and particularly the last there may in my judgement very sufficient Reasons be given without the Earths mobility by the mobility of the Heavens onely never introducing any novelty more than the inversion of that which you your self propose unto us It hath been received by the Peripatetick Schools that the Element of Fire and also a great part of the Aire is carried about according to the Diurnal conversion from East to West by the contact of the Concave of the Lunar Orb as by the Vessel their container Now without going out of your track I will that we determine the Quantity of the Aire which partaketh of that motion to distend so low as to the Tops of the highest Hills and that likewise they would reach to the Earth if those Mountains did not impede them which agreeth with what you say For as you affirm the Air which is invironed by ledges of Mountains to be carried about by the asperity of the moveable Earth we on the contrary say That the whole Element of Air is carried about by the motion of Heaven that part only excepted which lyeth below those bodies which is hindred by the asperity of the immoveable Earth And whereas you said That in case that asperity should be removed the Air would also cease to be whirld about we may say That the said asperity being removed the whole Aire would continue its motion Whereupon because the surfaces of spacious Seas are smooth and even the Airs motion shall continue upon those alwaies blowing from the East And this is more sensibly perceived in Climates lying under the Line and within the Tropicks where the motion of Heaven is swifter and like as that Celestial motion is able to bear before it all the Air that is at liberty so we may very rationally affirm that it contributeth the same motion to the Water moveable as being fluid and not connected to the immobility of the Earth And with so much the more confidence may we affirm the same in that by your confession that motion ought to be very small in resect of the efficient Cause which begirting in a natural day the whole Terrestrial Globe passeth many hundreds of miles an hour and especially towards the Equinoctial whereas in the currents of the open Sea it moveth but very few miles an hour And thus the voiages towards the West shall come to be commodious and expeditious not onely by reason of the perpetual Eastern Gale but of the course also of the Waters from which course also perhaps the Ebbing and Flowing may come by reason of the different scituation of the Terrestrial Shores against which the Water coming to beat may also return backwards with a contrary motion like as experience sheweth us in the course of Rivers for according as the Water in the unevenness of the Banks meeteth with some parts that stand out or make with their Meanders some Reach or Bay here the Water turneth again and is seen to retreat back a considerable space Upon this I hold That of those effects from which you argue the Earths mobility and alledge it as a cause of them there may be assigned a cause sufficiently valid retaining the Earth stedfast and restoring the mobility of Heaven SALV It cannot be denied but that your discourse is ingenious hath much of probability I mean probability in appearance but not in reality existence It consisteth of two parts In the first it assignes a reason of the continual motion of the Eastern Winde and also of a like motion in the Water In the second It would draw from the same Sourse the cause of the Ebbing and Flowing The first part hath as I have said some appearance of probability but yet extreamly less then that which we take from the Terrestrial motion The second is not onely wholly improbable but altogether impossible and false And coming to the first whereas it is said that the Concave of the Moon carrieth about the element of Fire and the whole Air even to the tops of the higher Mountains I answer first that it is dubious whether there be any element of Fire But suppose there be it is much doubted of the Orbe of the Moon as also of all the rest that is Whether there be any such solid bodies and vast or elss Whether beyond the Air there be extended a continuate expansion of a substance of much more tenuity and purity than our Air up and down which the Planets go wandring as now at last a good part of those very Phylosophers begin to think But be it in this or in that manner there is no reason for which the Fire by a simple contract to a superficies which you your self grant to be smooth and terse should be according to its whole depth carried round in a motion different from its natural inclination as hath been defusely proved and with sensible reasons demonstrated by Il Saggiatore Besides the other improbability of the said motions transfusing it self from the subtilest Fire throughout the Air much more dense and from that also again to the Water But that a body of rugged and mountainous surface by revolving in it self should carry with it the Air contiguous to it and against which its promontaries beat is not onely probable but necessary and experience thereof may be daily seen though without seeing it I believe that there is no judgement that doubts thereof As to the other part supposing that the motion of Heaven did carry round the Air and also the Water yet would that motion for all that have nothing to do with the Ebbing and Flowing For being that from one onely and uniform cause there can follow but one sole and uniform effect that which should be discovered in the Water would be a continuate and uniform course from East to West and in that a Sea onely which running compass environeth the whole Globe But in determinate Seas such as is the Mediterrane shut up in the East there could be no such motion For if its Water might be driven by the course of Heaven towards the West it would have been dry many ages since Besides that our Water runneth not onely towards the West But returneth backwards towards the East and that in ordinal Periods And whereas you say by the example of Rivers that though the course of the Sea were Originally that onely from East to West yet nevertheless the different Position of the Shores may make part of the Water regurgitate and return backwards I grant it you but it is necessary that you take notice my Simplicius that where the Water upon that account returneth backwards it doth so there perpetually and where it runneth straight forwards it runneth there alwayes in the same manner for so the example of the Rivers shewes you But in the case
many alterations for the more minute observations I remit them to be made by those that frequent several Seas and onely by way of a conclusion to this our conference I will propose to be considered how that the precise times of the fluxes and refluxes do not onely happen to be altered by the length of Straights and by the difference of depths but I believe that a notable alteration may also proceed from the comparing together of sundry tarcts of Sea different in greatness and in position or if you will inclination which difference happeneth exactly here in the Adriatick Gulph lesse by far than the rest of the Mediterrane and placed in so different an inclination that whereas that hath its bounds that incloseth it on the Eastern part as are the Coasts of Syria this is shut up in its more Westerly part and because the ebbings and flowings are much greater towards the extremities yea because the Seas risings and fallings are there onely greatest it may probably happen that the times of Flood at Venice may be the time of low Water in the other Sea which as being much greater and distended more directly from West to East cometh in a certain sort to have dominion over the Adriatick and therefore it would be no wonder in case the effects depending on the primary causes should not hold true in the times that they ought and that correspond to the periods in the Adriatick as it doth in the rest of the Mediterrane But these Particularities require long Observations which I neither have made as yet nor shall I ever be able to make the same for the future SAGR. You have in my opinion done enough in opening us the way to so lofty a speculation of which if you had given us no more than that first general Proposition that seemeth to me to admit of no reply where you declare very rationally that the Vessels containing the Sea-waters continuing stedfast it would be impossible according to the common course of Nature that those motions should follow in them which we see do follow and that on the other side granting the motions ascribed for other respects by Copernicus to the Terrestrial Globe these same alterations ought to ensue in the Seas if I say you had told us no more this alone in my judgment so far exceeds the vanities introduced by so many others that my meer looking on them makes me nauseate them and I very much admire that among men of sublime wit of which nevertheless there are not a few not one hath ever considered the incompatibility that is between the reciprocal motion of the Water contained and the immobility of the Vessel containing which contradiction seemeth to me now so manifest SALV It is more to be admired that it having come into the thoughts of some to refer the cause of the Tide to the motion of the Earth therein shewing a more than common apprehension they should in afterwards driving home the motion close with no side and all because they did not see that one simple and uniform motion as v. gr the sole diurnal motion of the Terrestrial Globe doth not suffice but that there is required an uneven motion one while accelerated and another while retarded for when the motion of the Vessels are uniforme the waters contained will habituate themselves thereto without ever making any alteration To say also as it is related of an ancient Mathematician that the motion of the Earth meeting with the motion of the Lunar Orb the concurrence of them occasioneth the Ebbing and Flowing is an absolute vanity not onely because it is not exprest nor seen how it should so happen but the falsity is obvious for that the Revolution of the Earth is not contrary to the motion of the Moon but is towards the same way So that all that hath been hitherto said and imagined by others is in my judgment altogether invalid But amongst all the famous men that have philosophated upon this admirable effect of Nature I more wonder at Kepler than any of the rest who being of a free and piercing wit and having the motion ascribed to the Earth before him hath for all that given his ear and assent to the Moons predominancy over the Water and to occult properties and such like trifles SAGR. I am of opinion that to these more spaculative persons the same happened that at present befalls me namely the not understanding the intricate commixtion of the three Periods Annual Monethly and Diurnal And how their causes should seem to depend on the Sun and on the Moon without the Suns or Moons having any thing to do with the Water a businesse for the full understanding of which I stand in need of a little longer time to consider thereof which the novelty and difficulty of it hath hitherto hindred me from doing but I despair not but that when I return in my solitude and silence to ruminate that which remaineth in my fancy not very well digested I shall make it my own We have now from these four dayes Discourse great attestations in favour of the Copernican Systeme amongst which these three taken the first from the Stations and Retrogradations of the Planets and from their approaches and recessions from the Earth the second from the Suns revolving in it self and from what is observed in its spots the third from the Ebbing and Flowing of the Sea do shew very rational and concluding SALV To which also haply in short one might adde a fourth and peradventure a fifth a fourth I say taken from the fixed stars seeing that in them upon exact observations those minute mutations appear that Copernicus thought to have been insensible There starts up at this instant a fifth novelty from which one may argue mobility in the Terrestrial Globe by means of that which the most Illustrious Signore Caesare of the noble Family of the Marsilii of Bologna and a Lyncean Academick discovereth with much ingenuity who in a very learned Tract of his sheweth very particularly how that he had observed a continual mutation though very slow in the Meridian line of which Treatise at length with amazement perused by me I hope he will communicate Copies to all those that are Students of Natures Wonders SAGR. This is not the first time that I have heard speak of the exquisite Learning of this Gentleman and of his shewing himself a zealous Patron of all the Learned and if this or any other of his Works shall come to appear in publique we may be aforehand assured that they will be received as things of great value SALV Now because it is time to put an end to our Discourses it remaineth that I intreat you that if at more leasure going over the things again that have been alledged you meet with any doubts or scruples not well resolved you will excuse my oversight as well for the novelty of the Notion as for the weaknesse of my wit as also
the Sun from the Summer Solstice 352 The Sun passeth one half of the Zodiack nine dayes sooner than the other 416 The Miracle in Joshuah of the Suns standing still answers not to the intent of lengthening the day but on the contrary excellently agreeth with the Copernican Systeme 456 The Sun without change of place revolveth upon its own Centre in the space of a Moneth 457 The Nobility of the Sun as being the Fountain of Light Heart of the World and Principle of Motion 457 The Suns standing still in Joshuah explained by Kepler 462 The Sun found to be neerer to us than in times past by five thousand Miles 469 The Sun Moon and Stars are one and the same thing 485 Why the Sun to our thinking moveth and not the Earth 486 How the Sun is said to rise and set by extrinsick denomination 489 The Sun is the King Heart and Lamp of the World 497 SYMPATHY Sympathy and Antipathy terms introduced by Phylosophers the more easily to give a reason of many Natural Effects 373 SYSTEM of Copernicus The Copernican System once admitted for true Expositions might be found out for all those Scriptures than that seem to make against it 459 Didacus à Stunica held that the Scripture may be best expounded by the Copernican System 468 SYSTEM of Vniverse The System of the Universe designed from the Appearances 296 The System of the Universe might probably have been intended to have been represented by the Golden Candlestick 500 The System represented likewise by the Apple in Paradice 501 T TELESCOPE The Telescope enableth us to discourse better of Celestial Matters than Aristotle himself 42 Invention of the Telescope taken from Aristotle 92 An ingenious Consideration about using of the Telescope with as much facility on the Round-top of the Mast of a Ship as on the Deck 225 The Mutations made in the Telescope depending on the Agitation of the Ship 226 The Operations of the Telescope accounted Fallacies by the Peripateticks 304 319 The Telescope is the best means to take away the Irradiations of the Stars 306 The Telescope hath much contributed to the Restauration of Astronomy 476 THEOLOGY Theology the Queen of the Sciences and wherein her Prerogative consists 44 THINGS Some Things are of that nature that their parts may seperate from one another and from their whole others not 492 Things are simply denominated in comparison of all or the greatest number of things of that kinde 496 THREE The Number Three celebrated amongst the Pythagoreans 2 TIDE The Tide and the Mobility of the Earth mutually confirm each other 380 Tyde Vide Ebbing and Flowing TRUE True and Fair are one and the same as also False and Deformed 115 For proof of True Conclusions many solid Arguments may be produced but to prove a false one none 112. 245 TRUTH and Truths Untruths cannot be Demonstrated as Truths are 112 The Truth sometimes gains strength by Contradiction 181 Truth hath not so little light as not to be discovered amongst the Umbrages of Falshoods 384 TYCHO The Argument of Tycho grounded upon a false Hypothesis 324 Tycho and his Followers never attempted to see whether there were any Phaenomena in the Firmament for or against the Annual Motion 337 Tycho and others argue against the Annual Motion from the invariable Elevation of the Pole 338 V VELOCITY Vniform Velocity sutable with Circular Motion 12 Nature doth not immediately conferre a determinate degree of Velocity although She could 12 The Velocity by the inclining plane equal to the Velocity by the Perpendicular and the Motion by the Perpendicular swifter than by the inclining plane 14 Velocities are said to be equal when the Spaces passed are proportionate to their times 15 The greater Velocity exactly compensates the greater Gravity 192 VENUS The Mutation of Figure in Venus argueth its Motion to be about the Sun 295 Venus very great towards the Vespertine Conjunction and very small towards the Matutine 297 Venus necessarily proved to move about the Sun 298 The Phaenomena of Venus appear contrary to the System of Copernicus 302 Another Difficulty raised by Venus against Copernicus 302 Venus according to Copernicus either lucid in it self or a transparent substance 302 The Reason why Venus and Mars do not appear to vary Magnitude so much as is requisite 303 A second Reason of the small apparent encrease of Venus 306 Venus renders the Errour of Astronomers in determining the Magnitude of Stars inexcuseable 327 VESSEL Of the Motion of Water in a Vessel Vide Water UNDERSTAND c. Man Understandeth very much intensive but little extensive 86 Humane Uuderstanding operates by Ratiocination 87 UNIVERSE The Constitution of the Uuiverse is one of the Noblest Problems a Man can study 187 The Centre of the Universe according to Aristotle is that Polnt about which the Celestial Spheres do revolve 294 Which ought to be accounted the Sphere of the Universe 299 It is a great rashnesse to censure that to be superfluous in the Universe which we do not perceive to be made for us 334 VURSTITIUS Christianus Vurstitius read certain Lectures touching the Opinion of Copernicus and what happened thereupon 110 W WATER He that had not heard of the Element of Water could never fancie to himself Ships and Fishes 47 An Experiment to prove the Reflection of Water less bright than that of the Land 81 The Motion of the Water in Ebbing and Flowing not interrupted by Rest. 251 The vain Argumentation of some to prove the Element of Water to be of a Spherical Superficies 377 The Progressive and uneven Motion makes the Water in a Vessel to run to and fro 387 The Several Motions in the conteining Vessel may make the conteined Water to rise and fall 387 The Water raised in one end of the Vessel returneth it self to Aequilibrium 391 In the shorter Vessels the Undulations of Waters are more frequent 391 The greater profundity maketh the Undulations of Water the more frequent 391 Why in narrow places the Course of the Waters is swifter than in larger 396 The cause why in some narrow Chanels we see the Sea Waters run alwayes one way 398 The Water more apt to conserve an Impetus conceived than the Air. 400 The Motion of the Water dependeth on the Motion of Heaven 404 WEIGHTS It s questionable whether Descending Weights move in a Right Line 21 WEST The Course to the West India's easie the return difficult 402 WINDE Constant Gales of Winde within the Tropicks blow towards the West 402 Windes from the Land make rough the Seas 402 WISDOME Divine Divine Wisdome infinitely infinite 85 The Discourses which Humane Reason makes in time the Divine Wisdom resolveth in a Moment that is hath them alwayes present 87 WIT. The Wit of Man admirably acute 87 The Pusilanimity of Popular Wits 364 Poetick Wits of two kinds 384 WORLD World Vide Universe The Worlds parts are according to Aristotle two Celestial and Elementary contrary to each other 6 The World
from him as the Agent to the Earth as the Subject doth sensibly glide forwards by reason of the Orbicular motion of the Earth and doth alwayes betake it self to some new place of her surface upon which ground he is truly said secundum vulgarem sermonem to move above and revolve about the Earth Not that the Sun doth move for by this Opinion we affirm the Earth to move that it may receive the Sun one while in one another while in another part of it but that at the motion of the Earth her self a contrary way the Quality diffused into her and impressed upon her by the Sun namely the Light of the Day is moved which riseth in one part of her and sets in another contrary to that according to the nature and condition of her motion And for this reason the Sun it self by consequence is said to rise and set which notwithstanding ex Hypothesi stands immoveable and that no otherwise then per donominationem extrinsecam as hath been said After this manner the command of Joshuah Sun stand thou still and the Miracle of the Suns cessation of Motion wrought by him may be so understood as that not the Solar Body properly but the Suns splendour upon the Earth stood still so that not the Sun it self being of it self before that time immoveable but the Earth that receiveth its splendour stayed her Motion which as she incessantly pursuing her ordinary Motion towards the East called up the Light of the Sun in the West so standing still the Suns light imprest upon it likewise stood still After the same manner proportionally is that Text of Isaiah explained touching the Suns going ten degrees backward upon the Dial of Ahaz So which may serve for another Example the Hand being moved about the flame of a burning Candle that stand◠still the Light moveth on the Hand that is to say the said Hand is illustrated now in one part anon in another when as the Candle it self all the while removes not out of its place whereupon per denominationem extrinsecam the said Light may be affirmed to rise and set upon the Hand namely by the sole motion of the said Hand the Candle it self never moving all the while And let this suffice for the explanation of my first Principle or Maxime which by reason of its difficulty and extraordinary weight required some prolixity in the handling of it My second Maxime is this Things both Spiritual and Corporeal Durable and Corruptible Moveable and Immoveable have received from God a perpetual unchangeable and inviolable Law constituting the Essence and Nature of every one of them according to which Law all of them in their own Nature persisting in a certain Order and Constancy and observing the same perpetual Course may deservedly be stiled most Stable and Determinate Thus Fortune than which there is nothing in the World more inconstant or fickle is said to be constant and unalterable in her continual volubility vicissitude and inconstancy which was the occasion of that Verse Et semper constans in levitate sua est And thus the motion of Heaven which by the constan Law of Nature ought to be perpetual may be said to be immutable and immoveable and the Heavens themselves to be immoveably moved and Terrene things to be immutably changed because those never cease moving nor these changing By this Principle or Maxime all difficulties belonging to the first Classis are cleared by which the Earth is said to be stable and immoveable that is by understanding this one thing That the Earth as to its own Nature though it include in it self a local Motion and that threefold according to the opinion of Copernicus scilicet Diurnal with which it revolveth about its own Centre Annual by which it moveth through the twelve Signes of the Zodiack and the motion of Inclination by which its Axis is alwayes opposed to the same part of the World as also other Species of Mutation such as Generation and Corruption Accretion and Diminution and Alteration of divers kinds yet in all these she is stable constant never deviating from that Order which God hath appointed her but moveth continually constantly and immutably according to the six before named Species of Motion My third Maxime shall be this When a thing is moved according to some part of it and not according to its whole it cannot be said to be simply absolutely moved but only per accidens for that stability taken simply absolutly do rather accord with the same As for example if a Barrel or other measure of Water be taken out of the Sea and transferred to another place the Sea may not therefore absolutely simply be said to be removed from place to place but only per accidens and secundum quid that is according to a part of it but rather to speak simply we should say that the Sea cannot be carried or moved out of its proper place though as to its parts it be moved and transferred to again This Maxime is manifest of it self and by it may the Authorities be explained which seem to make for the immobility of the Earth in this manner namely The Earth per se absolutè considered as to its Whole is not mutable seeing it is neither generated nor corrupted neither increased nor diminished neither is it altered secundum totum but only secundum partes Now it plainly appears that this is the genuine and true Sense of what is ascribed to it out of Ecclesiastes cap. 1. v. 4. One Generation passeth away and another Generation cometh but the Earth abideth for ever as if he should say although the Earth according to its parts doth generate and corrupt and is liable to the vicissitudes of Generation and corruption yet in reference to its Whole it never generateth nor Corrupteth but abideth immutable for ever Like as a Ship which though it be mended one while in the Sail-yard another while in the Stern and afterwards in other parts it yet remains the same Ship as it was at first But t is to be advertized that that Scripture doth not speak of a Local Motion but of Mutations of another nature as in the very substance quantity or quality of the Earth it self But if it be said that it is to be understood of a Local Motion then it may be explained by the insuing Maxime that is to say a respect being had to the natural Place assigned it in the Universe as shall be shewed by and by The fourth Axiome is this That every Corporeal thing moveable or immoveable from its very first Creation is alotted its proper and natural place and being drawn or removed from thence its motion is violent and it hath a natural tendency to move back thither again also that nothing can be moved from its natural place secundum Totum For most great and dreadful mischiefs would follow from that perturbation of things in the Universe
is than the thread passed the hole the greater reciprocally is the velocity of the parts of the thread passed the hole than the volocity of the parts before the hole Insomuch that if verbi gratia the thicknesse of the thread before the hole were double to the thicknesse after the hole in such case the velocity of the parts of the thread passed the hole should be double to the velocity of the parts of the thread before the hole and thus the thicknesse compensates the velocity and the velocity compensates the thicknesse So that the same occurreth in the solid Metals of Gold Silver Brass Iron c. that eveneth also in the fluid Element of Water and other liquids namely That the velocity beareth the same proportion to the velocity that the thicknesse of the Metal or Water hath to the thicknesse And therefore granting this discourse we may say that as often as two Taps with different velocity discharge equal quantities of Water in equal times it will be necessary that the Tap lesse swift be so much greater and larger than the Tap more swift by how much the swifter superates in velocity the slower and to pronounce the Proposition in more proper terms we say That if two Taps of unequal velocity discharge in equal times equal quantities of Water the greatnesse of the first shall be to the greatnesse of the second in reciprocal proportion as the velocity of the second to the velocity of the first As for example if the first Tap shall be ten times swifter than the second Tap it will be necessary that the second be ten times bigger and larger than the first and in such case the Taps shall discharge equall quantities of water in equal times and this is the principal and most important point which ought to be kept alwayes in minde for that on it well understood depend many things profitable and worthy of our knowledge Now applying all that hath been said neerer to our purpose I consider that it being most true that in divers parts of the same River or Current of running water there doth always passe equal quantity of Water in equal time which thing is also demonstrated in our first Proposition and it being also true that in divers parts the same River may have various and different velocity it follows of necessary consequence that where the River hath lesse velocity it shall be of greater measure and in those parts in which it hath greater velocity it shall be of lesse measure and in sum the velocity of several parts of the said River shall have eternally reciprocall and like proportion with their measures This principle and fundamental well established that the same Current of Water changeth measure according to its varying of velocity that is lessening the measure when the velocity encreaseth and encreasing the measure when the velocity decreaseth I passe to the consideration of many particular accidents in this admirable matter and all depending on this sole Proposition the sense of which I have oft repeated that it might be well understood COROLLARIE I. ANd first we hence conclude that the same Streams of a Torrent namely those streams which carry equal quantity of Water in equal times make not the same depths or measures in the River in which they enter unlesse when in the entrance into the River they acquire or to say better keep the same velocity because if the velocicities acquired in the River shall be different also the measures shall be diverse and consequently the depths as is demonstrated COROLLARIE II. ANd because successively as the River is more and more full it is constituted ordinarily in greater greater velocity hence it is that the same streams of the Torrent that enter into the River make lesse and lesse depths as the River grows more and more full since that also the Waters of the Torrent being entered into the River go acquiring greater and greater velocities and therefore diminish in measure and height COROLLARIE III. WE observe also that while the main River is shallow if there fall but a gentle rain it suddenly much increaseth and riseth but when the River is already swelled though there fall again another new violent shower yet it increaseth not at the same rate as before proportionably to the rain which fell which thing we may affirm particularly to depend on this that in the first case while the River is low it is found also very slow and therefore the little water which entereth into it passeth and runs with little velocity and consequently occupieth a great measure But when the River is once augmented by new water being also made more swift it causeth the great Flood of water which falleth to bear a lesse measure and not to make such a depth COROLLARIE IV. FRom the things demonstrated is manifest also that whilst a Torrent entereth into a River at the time of Ebbe then the Torrent moveth with such a certain velocity what ever it be passing by its extreamest parts wherewith it communicateth with the River in which parts the Torrent being measured shall have such a certain measure but the River swelling and rising also those parts of the Torrent augment in greatnesse and measure though the Torrent in that instant dis-imbogue no more water than it did before so that the River being swelled we are to consider two mouths of the same Torrent one lesse before the rising the other greater after the rising which mouths discharge equal quantities of water in equal times therefore the velocity by the lesser mouth shall be greater than the velocity by the greater mouth and thus the Torrent shall be retarded from its ordinary course COROLLARIE V. FRom which operation of Nature proceedeth another effect worthy of consideration and it is that the course of the water retarding as hath been said in those ultimate parts of the Torrent if it shall happen that the Torrent grow torbid and muddy and its streame be retarded in such a degree that it is not able to carry away those minute grains of Earth which compose the muddinesse in this case the Torrent shall clear away the mud and carry away the Sand at the bottome of its own Chanel in the extream parts of its mouth which raised and voided Sand shall again afterwards be carried away when the River abating the Torrent shall return to move with its primitive velocity COROLLARIE VI. WHilst it is demonstrated that the same water hath different measures in its Chanel or course according as it varieth in velocity so that the measure of the water is alwayes greater where the velocity is lesser and on the contrary the measure lesser where the velocity is greater from hence we may most elegantly render the reason of the usual Proverb Take heed of the still waters For that if we consider the self same water of a River in those parts wherein it is less swift and thence called still or smooth water it shall be of necessity of
in the lower parts namely below the breach there is begot in the Channel of the River a certain ridge or shelf that is the bottom of the River is raised as is sufficiently manifest by experience and thus just in the same manner cutting the Bank at Bondeno there is at it were a breach made from which followeth the rising in the lower parts of the main Po being past the mouth of Pamaro which thing how pernitious it is let any one judge that understandeth these matters And therefore both for the small benefit and so many harms that ensue from maintaining this diversion I should think it were more sound advice to keep that Bank alwaies whole at Bondeno or in any other convenient place and not to permit that the Water of the Grand Po should ever come near to Ferara COROLLARIE XIV IN the Grand Rivers which fall into the Sea as here in Italy Po Adige And Arno which are armed with Banks against their excrescencies it s observed that far from the Sea they need Banks of a notable height which height goeth afterwards by degrees diminishing the more it approacheth to the Sea-coasts in such sort that the Po distant from the Sea about fifty or sixty miles at Ferara shall have Banks that be above twenty feet higher than the ordinary Water-marks but ten or twelve miles from the Sea the Banks are not twelve feet higher than the said ordinary Water-marks though the breadth of the River be the same so that the excrescence of the same Innundation happens to be far greater in measure remote from the Sea then near and yet it should seem that the same quantity of Water passing by every place the River should need to have the same altitude of Banks in all places But we by our Principles and fundamentals may be able to render the reason of that effect and say That that excesse of quantity of Water above the ordinary Water goeth alwaies acquiring greater velocity the nearer it approacheth the Sea and therefore decreaseth in measure and consequently in height And this perhaps might have been the cause in great part why the Tyber in the Innundation Anno 1578. issued not forth of its Channel below Rome towards the Sea COROLLARIE XV. FRom the same Doctrine may be rendred a most manifest reason why the falling Waters go lessening in their descent so that the same falling Water measured at the beginning of its fall is greater and bigger and afterwards by degrees lesseneth in measure the more it is remote from the beginning of the fall Which dependeth on no other than on the acquisition which it successively makes of greater velocity it being a most familiar conclusion among Philosophers that grave bodies falling the more they remove from the beginning of their motion the more they acquire of swiftnesse and therefore the Water as a grave body falling gradually velocitates and therefore decreaseth in measure and lesseneth COROLLARIE XVI ANd on the contrary the spirtings of a Fountain of Water which spring on high work a contrary effect namely in the beginning they are small and afterwards become greater and bigge and the reason is most manifest because in the beginning they are very swift and afterwards gradually relent their impetuosity and motion so that in the beginning of the excursion that they make they ought to be small and afterwards to grow bigger as in the effect is seen APPENDIX I. INto the errour of not considering how much the different velocities of the same running water in several places of its current are able to change the measure of the same water and to make it greater or lesse I think if I be not deceived that Ginlio Frontino a noble antient Writer may have faln in the Second Book which he writ of the Aqueducts of the City of Rome Whilst finding the measure of the Water Commentariis lesse than it was in erogatione 1263. Quinaries he thought that so much difference might proceed from the negligence of the Measures and when afterwards with his own industry he measured the same water at the beginning of the Aqueducts finding it neer 10000. Quinaries bigger than it was in Commentariis he judged that the overplus was imbeziled by Ministers and Partakers which in part might be so for it is but too true that the publique is almost alwayes defrauded yet neverthelesse I verily believe withal that besides the frauds of these Officers the velocities of the water in the place wherein Frontino measured it might be different from those velocities which are found in other places before measured by others and therefore the measures of the waters might yea ought necessarily to be different it having been by us demonstrated that the measures of the same running water have reciprocal proportion to their velocities Which Frontino not well considering and finding the water in Commentariis 12755. Quinaries in erogatione 14018 and in his own measure ad capita ductuum at the head of the fountain 22755. Quinaries or thereabouts he thought that in all these places there past different quantities of water namely greater at the fountain head then that which was in Erogatione and this he judged greater than that which was in Commentariis APPENDIX II. A Like mistake chanced lately in the Aqueduct of Acqua-Paola which Water should be 2000 Inches and so many effectively ought to be allowed and it hath been given in so to be by the Signors of Bracciano to the Apostolick-Chamber and there was a measure thereof made at the beginning of the Aqueduct which measure proved afterwards much lesse and short considered and taken in Rome and thence followed discontents and great disorders and all because this property of Running-Waters of increasing in measure where the velocity decreased and of diminishing in measure where the velocity augmented was not lookt into APPENDIX III. A Like errour in my judgement hath been committed by all those learned men which to prevent the diversion of the Reno of Bologna into Po by the Channels through which it at present runneth judged that the Reno being in its greater excrescence about 2000. feet and the Po being near 1000. feet broad they judged I say that letting the Reno into Po it would have raised the Water of Po two feet from which rise they concluded afterwards most exorbitant disorders either of extraordinary Inundations or else of immense and intolerable expences to the people in raising the Banks of Po and Reno and with such like weaknesses often vainly disturbed the minds of the persons concerned But now from the things demonstrared it is manifest That the measure of the Reno in Reno would be different from the measure of Reno in Po in case that the velocity of the Reno in Po should differ from the velocity of Reno in Reno as is more exactly determined in the fourth Proposition APPENDIX IV. NO less likewise are those Ingeneers and Artists deceived that have affirmed That letting the Reno into Po there would be
prejudice of all the places and villages circumjacent in regard that the Water which used to run from the said Lake turned 22 Mills which not going necessitated the inhabitants of those parts to go a dayes journey and more to grinde upon the Tiber. Being returned to Perugia there followed a Rain not very great but constant and even which lasted for the space of eight hours or thereabouts and it came into my thoughts to examine being in Perugia how much the Lake was increased and raised by this Rain supposing as it was probable enough that the Rain had been universal over all the Lake and like to that which fell in Perugia and to this purpose I took a Glasse formed like a Cylinder about a palme high and half a palme broad and having put in water sufficient to cover the bottome of the Glasse I noted diligently the mark of the height of the Water in the Glasse and afterwards exposed it to the open weather to receive the Raine-water which fell into it and I let it stand for the space of an hour and having observed that in that time the Water was risen in the Vessel the height of the following line I considered that if I had exposed to the same rain such other vessels equal to that the Water would have risen in them all according to that measure And thereupon concluded that also in all the whole extent of the Lake it was necessary the Water should be raised in the space of an hour the same measure Yet here I considered two difficulties that might disturb and altar such an effect or at least render it inobserveable which afterwards well weighed and resolved left me as I will tell you anon in the conclusion the more confirmed that the Lake ought to be increased in the space of eight hours that the rain lasted eight times that measure And whilst I again exposed the Glass to repeat the experiment there came unto me an Ingeneer to talk with me touching certain affairs of our Monastary of Perugia and discoursing with him I shewed him the Glass out at my Chamber-window exposed in a Court-yard and communicated to him my fancy relating unto him all that I had done But I soon perceived that this brave fellow conceited me to be but of a dull brain for he smiling said unto me Sir you deceive your self I am of opinion that the Lake will not be increased by this rain so much as the thicknesse of Julio Hearing him pronounce this his opinion with freeness and confidence I urged him to give me some reason for what he said assuring him that I would change my judgement when I saw the strength of his Arguments To which he answered that he had been very conversant about the Lake and was every day upon it and was well assured that it was not at all increased And importuning him further that he would give me some reason for his so thinking he proposed to my consideration the great drought passed and that that same rain was nothing for the great parching To which I answered I believe Sir that the surface of the Lake on which the rain had fallen was moistned and therefore saw not how its drought which was nothing at all could have drunk up any part of the rain For all this he persisting in his conceit without yielding in the least to my allegation he granted in the end I believe in civility to me that my reason was plausible and good but that in practise it could not hold At last to clear up all I made one be called and sent him to the mouth of the Emissary of the Lake with order to bring me an exact account how he found the water of the Lake in respect of the Transome of the Sluice Now here Signore Galilaeo I would not have you think that I had brought the matter in hand to concern me in my honour but believe me and there are witnesses of the same still living that my messenger returning in the evening to Perugia he brought me word that the water of the Lake began to run through the Cave and that it was risen almost a fingers breadth above the Transome Insomuch that adding this measure to that of the lowness of the surface of the Lake beneath the Transome before the rain it was manifest that the rising of the Lake caused by the rain was to a hair those four fingers breadth that I had judged it to be Two dayes after I had another bout with the Ingeneer and related to him the whole business to which he knew not what to answer Now the two difficulties which I thought of able to impede my conclusion were these following first I considered that it might be that the Wind blowing from the side where the Sluice stood to the Lake-ward the mole and mass of the Water of the Lake might be driven to the contrary shore on which the Water rising it might be fallen at the mouth of the Emissary and so the observation might be much obscured But this difficulty wholly vanished by reason of the Aires great tranquility which it kept at that time for no Wind was stirring on any side neither whilst it rained nor afterwards The second difficulty which put the rising in doubt was That having observed in Florence and elsewhere those Ponds into which the rain-water falling from the house is conveyed through the Common-shores And that they are not thereby ever filled but that they swallow all that abundance of water that runs into them by those conveyances which serve them with water insomuch that those conveyances which in time of drought maintain the Pond when there come new abundance of water into the Pond they drink it up and swallow it A like effect might also fall out in the Lake in which there being many veins as it is very likely that maintain and feed the Lake these veins might imbibe the new addition of the Rain-water and so by that means annull the rising or else diminish it in such sort as to render it inobservable But this difficulty was easily resolved by considering my Treatise of the measure of Running-Waters forasmuch as having demonstrated that the abatement of a Lake beareth the reciprocal proportion to the velocity of the Emissary which the measure of the Section of the Emissary of the Lake hath to the measure of the surface of the Lake making the calculation and account though in gross by supposing that its veins were sufficiently large and that the velocity in them were notable in drinking up the water of the Lake yet I found nevertheless that many weeks and moneths would be spent in drinking up the new-come abundance of water by the rain so that I rested sure that the rising would ensue as in effect it did And because many of accurate judgement have again caused me to question this rising setting before me that the Earth being parched by the great drought that had so long continued it
GENERAL of the HOLY CHURCH LONDON Printed Anno Domini MDCLXI OF THE MENSURATION OF Running Waters SUPPOSITION I. LEt it be supposed that the banks of the Rivers of which we speak be erected perpendicular to the plane of the upper superficies of the River SUPPOSITION II. WE suppose that the plane of the bottome of the River of which we speak is at right angles with the banks SUPPOSITION III. IT is to be supposed that we speak of Rivers when they are at ebbe in that state of shallownesse or at flowing in that state of deepnesse and not in their transition from the ebbe to the flowing or from the flowing to the ebbe Declaration of Termes FIRST IF a River shall be cut by a Plane at right angles to the surface of the water of the River and to the banks of the River that same dividing Plane we call the Section of the River and this Section by the Suppositions above shall be a right angled Parallelogram SECOND WE call those Sections equally Swift by which the water runs with equal velocity and more swift and less swift that Section of another by which the water runs with greater or lesse velocity AXIOME I. SEctions equal and equally swift discharge equal quantities of Water in equal times AXIOME II. SEctions equally swift and that discharge equal quantity of Water in equal time shall be equal AXIOME III. SEctions equal and that discharge equal quantities of Water in equal times shall be equally swift AXIOME IV. WHen Sections are unequal but equally swift the quantity of the Water that passeth through the first Section shall have the same proportion to the quantity that passeth through the Second that the first Section hath to the second Section Which is manifest because the velocity being the same the difference of the Water that passeth shall be according to the difference of the Sections AXIOME V. IF the Sections shall be equal and of unequal velocity the quantity of the Water that passeth through the first shall have the same proportion to that which passeth through the second that the velocity of the first Section shall have to the velocity of the second Section Which also is manifest because the Sections being equal the difference of the Water which passeth dependeth on the velocity PETITION A Section of a River being given we may suppose another equal to the given of different breadth height and velocity PROPOSITION I. The Sections of the same River discharge equal quantities of Water in equal times although the Sections themselves he unequal LEt the two Sections be A and B in the River C running from A towards B I say that they discharge equal quantity of Water in equal times for if greater quantity of Water should pass through A than passeth through B it would follow that the Water in the intermediate space of the River C would increase continually which is manifestly false but if more Water should issue through the Section B than entreth at the Section A the Water in the intermediate space C would grow continually less and alwaies ebb which is likewise false therefore the quantity of Water that passeth through the Section B is equal to the quantity of Water which passeth through the Section A and therefore the Sections of the same River discharge c. Which was to be demonstrated PROPOSITION II. In two Sections of Rivers the quantity of the Water which passeth by one Section is to that which passeth by the second in a Proportion compounded of the proportions of the first Section to the second and of the velocitie through the first to the velocitie of the second LEt A and B be two Sections of a River I say that the quantity of Water which passeth through A is to that which passeth through B in a proportion compounded of the proportions of the first Section A to the Section B and of the velocity through A to the velocity through B Let a Section be supposed equal to the Section A in magnitude but of velocity equal to the Section B and let it be G and as the Section A is to the Section B so let the line F be to the line D and as the velocity A is to the velocity by B so let the line D be to the line R Therefore the Water which passeth thorow A shall be to that which passeth through G in regard the Sections A and G are of equal bigness but of unequal velocity as the velocity through A to the velocity through G But as the velocity through A is to the velocity through G so is the velocity through A to the velocity through B namely as the line D to the line R therefore the quantity of the Water which passe the through A shall be to the quantity which passeth through G as the line D is to the line R but the quantity which passeth through G is to that which passeth through B in regard the Sections C and B are equally swift as the Section G to the Section B that is as the Section A to the Section B that is as the line F to the line D Therefore by the equal and perturbed proportionality the quantity of the Water which passeth through A hath the same proportion to that which passeth through B that the line F hath to the line R but F to R hath a proportion compounded of the proportions of F to D and of D to R that is of the Section A to the Section B and of the velocity through A to the velocity through B Therefore also the quantity of Water which passeth through the Section A shall have a proportion to that which passeth through the Section B compounded of the proportions of the Section A to the Section B and of the velocity through A to the velocity through B And therefore in two Sections of Rivers the quantity of Water which passeth by the first c. which was to be demonstrated COROLLARIE THe same followeth though the quantity of the Water which passeth through the Section A be equal to the quantity of Water which passeth through the Section B as is manifest by the same demonstration PROPOSITION III. In two Sections unequal through which pass equal quantities of Water in equal times the Sections have to one another reciprocal proportion to their velocitie LEt the two unequal Sections by which pass equal quantities of Water in equal times be A the greater and B the lesser I say that the Section A shall have the same Proportion to the Section B that reciprocally the velocity through B hath to the velocity through A for supposing that as the Water that passeth through A is to that which passeth through B so is the line E to the line F therefore the quantity of water which passeth through A being equal to that which passeth through B the line E shall also be equal to the line F Supposing moreover That as the Section A is to the Section B so is the
which was to be demonstrated ANNOTATION THe same might have been demonstrated by the second Proposition above demonstrated as is manifest PROPOSITION VI. If two equal streams of the same Torrent fall into a River at divers times the heights made in the River by the Torrent shall have between themselves the reciprocal proportion of the velocities acquired in the River LEt A and B be was equal streams of the same Torrent which falling into a River at divers times make the heights CD and FG that is the stream A maketh the height CD and the stream B maketh the height FG that is Let their Sections in the River into which they are fallen be CE and FH I say that the height CD shall be to the height FG in reciprocal proportion as the velocity through FH to the velocity through CE for the quantity of water which passeth through A being equal to the quantity which passeth through B in equal times also the quantity which passeth through CE shall be equal to that which passeth through FH And therefore the proportion that the Section CE hath to the Section FH shall be the same that the velocity through FH hath to the velocity through CE But the Section CE is to the Section FH as CD to FG by reason they are of the same breadth Therefore CD shall be to FG in reciprocal proportion as the velocity through FH is to the velocity through CE and therefore if two equal streams of the same Torrent c. which was to be demonstrated OF THE MENSURATION OF Running Waters Lib. II. HAving in the close of my Treatise of the Mensuration of Running Waters promised to declare upon another occasion other particulars more obscure and of very great concern upon the same argument I now do perform my promise on the occasion that I had the past year 1641. to propound my thoughts touching the state of the Lake of Venice a business certainly most important as being the concernment of that most noble and most admirable City and indeed of all Italy yea of all Europe Asia Africa one may truly say of all the whole World And being to proceed according to the method necessary in Sciences I wil propose in the first place certain Definitions of those Terms whereof we are to make use in our Discourse and then laying down certain Principles we will demonstrate some Problemes and Theoremes necessary for the understanding of those things which we are to deliver and moreover recounting sundry cases that have happened we will prove by practice of what utility this contemplation of the Measure of Running Waters is in the more important affairs both Publique and Private DEFINITION I. TWo Rivers are said to move with equal velocity when in equal times they passe spaces of equal length DEFINITION II. RIvers are said to move with like velocity when their proportional parts do move alike that is the upper parts alike to the upper and the lower to the lower so that if the upper part of one River shall be more swift than the upper part of another then also the lower part of the former shall be more swift than the part correspondent to it in the second proportionally DEFINITION III. TO measure a River or running Water is in our sense to finde out how many determinate measures or weights of Water in a given time passeth through the River or Channel of the Water that is to be measured DEFINITION IV. IF a Machine be made either of Brick or of Stone or of Wood so composed that two sides of the said Machine be placed at right angles upon the ends of a third side that is supposed to be placed in the bottom of a River parallel to the Horizon in such a manner that all the water which runneth through the said River passeth thorow the said Machine And if all the water coming to be diverted that runneth through the said River the upper superficies of that third side placed in the bottom do remain uncovered and dry and that the dead water be not above it This same Machine shall be called by us REGULATOR And that third side of the Machine which standeth Horizontally is called the bottom of the Regulator and the other two sides are called the banks of the Regulator as is seen in this first Figure ABCD shall be the Regulator BC the bottom and the other two sides AB and CD are its banks DEFINITION V. BY the quick height we mean the Perpendicular from the upper superficie of the River unto the upper superficies of the bottom of the Regulator as in the foregoing Figure the line GH DEFINITION VI. IF the water of a River be supposed to be marked by three sides of a Regulator that Rightangled Parallelogram comprehended between the banks of the Regulator and the bottom and the superficies of the Water is called a Section of the River ANNOTATION HEre it is to be noted that the River it self may have sundry and divers heights in several parts of its Chanel by reason of the various velocities of the water and its measures as hath been demonstrated in the first book SUPPOSITION I. IT is supposed that the Rivers equal in breadth and quick height that have the same inclination of bed or bottom ought also to have equal velocities the accidental impediments being removed that are dispersed throughout the course of the water and abstracting also from the external windes which may velocitate and retard the course of the water of the River SUPPOSITION II. LEt us suppose also that if there be two Rivers that are in their beds of equal length and of the same inclination but of quick heights unequal they ought to move with like velocity according to the sense explained in the second definition SUPPOSITION III. BEcause it will often be requisite to measure the time exactly in the following Problems we take that to be an excellent way to measure the time which was shewed me many years since by Signore Galilaeo Galilaei which is as followeth A string is to be taken three Roman feet long to the end of which a Bullet of Lead is to be hanged of about two or three ounces and holding it by the other end the Plummet is to be removed from its perpendicularity a Palm more or less and then let go which will make many swings to and again passing and repassing the Perpendicular before that it stay in the same Now it being required to measure the time that is spent in any whatsoever operation those vibrations are to be numbred that are made whilst the work lasteth and they shall be so many second minutes of an hour if so be that the string be three Roman feet long but in shorter strings the vibrations are more frequent and in longer less frequent and all this still followeth whether the Plummet be little or much removed from its Perpendicularity or whether the weight of the Lead be greater or lesser These
set down the whole businesse in writing who having afterwards read it privately the said Signore imparted the same with like privacy to the most Serene PRINCE and I received order to represent the same to the full Colledge as accordingly I did in the Moneth of May the same year and it was as followeth CONSIDERATIONS Concerning the LAKE OF VENICE BY D. BENEDETTO CASTELLI Abbot of S. Benedetto Aloysio Mathematician to Pope VRBAN VIII and Professor in ROME CONSIDERATION I. THough the principal cause be but one onely that in my judgment threatneth irreparable ruine to the Lake of Venice in the present state in which it now stands Yet neverthelesse I think that two Heads may be considered And this Consideration may peradventure serve us for to facilitate and explain the opportune remedies though not to render the state of things absolutely unchangeable and eternal an enterprize impossible and especially in that which having had some beginning ought likewise necessarily to have its end or at least to prevent the danger for many hundreds of years and possibly it may in the mean time by the mutation it self be brought into a better condition I say therefore that the present disorder may be considered under two Heads One is the very notable discovery of Land that is observed at the time of low Water the which besides the obstructing of Navigation in the Lake and also in the Chanels doth likewise threaten another mischief and disorder worthy of very particular consideration which is That the Sun drying up that mudde especially in the times of hot Summers doth raise thence the putrified and pernicious vapours fogs and exhalations that infect the Air and may render the City unhabitable The second Head is the great Stoppage that daily is growing in the Ports especially of Venice at Malamoco concerning which matters I will hint certain general points and then will proceed to the more particular and important affairs And first I say that I hold it altogether impossible to effect any thing though never so profitable which doth not bring with it some mischief and therefore the good and the hurt ought to be very well weighed and then the lesse harmful part to be imbraced Secondly I propose to consideration that the so notable discovery of Earth Mud hath not been long observed as I understand from old persons that can remember passages for fifty years past which thing being true as to me it seemeth most true it should appear that it could not but be good to reduce matters to that passe that they were at formerly laying aside all affection or passion that self-flattering minds have entertained for their own conceits or at least it shall be necessary speedily to consult the whole Thirdly I hold that it is necessary to weigh whether from the foresaid discovery of Land it followeth that onely the Earth riseth as it is commonly thought by all without dispute or whether the Waters are abated and faln away or else whether it proceedeth from both the one and other cause And here it would be seasonable to enquire what share the said causes may have each considered apart in the foresaid effect For in the first case if the Earth have been raised it would be necessary to consider of taking it down and removing it But if the Waters have failed or abated I believe that it would be extreamly necessary to restore and raise them And if both these reasons have conspired in this effect it will be necessary to remedy them each apart And I do for my part think that the so notable appearance of Shelves at the time of low Water proceeds principally from the decrease and abatement of the Waters which may confidently be affirmed to need no other proof in regard that the Brent hath been actually diverted which did formerly discharge its Water into the Lake As to the other point of the great Stoppage of Ports I hold that all proceedeth from the violence of the Sea which being sometimes disturbed by windes especially at the time of the waters flowing doth continually raise from its bottome immense heaps of sand carrying them by the tide and force of the waves into the Lake it not having on its part any sttength of current that may raise and carry them away they sink to the bottom and so they choke up the Ports And that this effect happeneth in this manner we have most frequent experiences thereof along the Sea-coasts And I have observed in Tuscany on the Roman-shores and in the Kingdom of of Naples that when a river falleth into the Sea there is alwaies seen in the Sea it self at the place of the rivers out-let the resemblance as it were of an half-Moon or a great shelf of settled sand under water much higher then the rest of the shore and it is called in Tuscany il Cavallo and here in Venice lo Scanto the which cometh to be cut by the current of the river one while on the right side another while on the left and sometimes in the midst according as the Wind sits And a like effect I have observed in certain little Rillets of water along the Lake of Bolsena with no other difference save that of small and great Now who so well considereth this effect plainly seeth that it proceeds from no other than from the contrariety of the stream of the River to the impetus of the Sea-waves seeing that great abundance of sand which the Sea continually throws upon the shore cometh to be driven into the Sea by the stream of the river and in that place where those two impediments meet with equal force the sand setleth under water and thereupon is made that same Shelf or Cavallo the which if the river carry water and that any considerable store it shall be thereby cut and broken one while in one place and another while in another as hath been said according as the Wind blows And through that Chanel it is that Vessels fall down into the Sea and again make to the river as into a Port. But if the Water of the river shall not be continual or shall be weak in that case the force of the Sea-Wind shall drive such a quantity of sand into the mouth of the Port and of the river as shall wholly choak it up And hereupon there are seen along the Sea-side very many Lakes and Meers which at certain times of the year abound with waters and the Lakes bear down that enclosure and run into the Sea Now it is necessary to make the like reflections on our Ports of Venice Malamocco Bondolo and Chiozza which in a certain sense are no other than Creeks mouths and openings of the shore that parts the Lake from the main Sea and therefore I hold that if the Waters in the Lake were plentiful they would have strength to scowr the mouths of the Ports thorowly with great force but the Water in the Lake failing the Sea will without any opposal
bring such a drift of sand into the Ports that if it doth not wholly choke them up it shall render them at least unprofitable and impossible for Barks and great Vessels Many other considerations might be propounded concerning these two heads of the stoppage of the Ports and of the appearance of the Ouze and Mud in the Lakes but so much shall suffice us to have hinted to make way for discoursing of the operations about the oportune remedies Yet before that I propound my opinion I say That I know very well that my proposal at first sight will seem absurd and inconvenient and therefore as such will perhaps be rejected by the most and so much the rather for that it will prove directly contrary to what hath hitherto been and as I hear is intended to be done And I am not so wedded to my opinions but that I do consider what others may judge thereof But be it as it will I am obliged to speak my thoughts freely and that being done I will leave it to wiser men than my sâ—lf when they shall have well considered my reasons to judge and deliberate of the quid agendum And if the sentence shall go against me I appeal to the most equitable and inexorable Tribunal of Nature who not caring in the least to please either one party or another will be alwaies a punctual and inviolable executrix of her eternal Decrees against which neither humane deliberations nor our vain desires shall ever have power to rebell I added by word of mouth that which followeth Though your Highness interest your self in this Noble Colledge and cause it to be confirmed in the Senate by universal Vote that the Winds do not blow that the Sea doth not fluctuate that the Rivers do not run yet shall the Winds be alwaies deaf the Sea shall be constant in its inconstancy and the Rivers most obstinate And these shall be my Judges and to their determination I refer my self By what hath been said in my opinion that is made very clear and manifest which in the beginning of this discourse I glanced at namely That the whole disorder although it be divided into two heads into the discovery of the Mud and of the stoppage Ports yet nevertheless by the application of one onely remedy and that in my esteem very easie the whole shall be removed And this it is That there be restored into the Lake as much Water as can be possible and in particular from the upper parts of Venice taking care that the Water be as free from Mud as is possible And that this is the true and real remedy of the precedent disorders is manifest For in the passage that this Water shall make thorow the Lakes it shall of it self by degrees clear the Chanels in sundry parts of them according to the currents that it shall successively acquire and in this manner being dispersed thorow the Lake it shall maintain the waters in the same and in the Chanels much higher as I shall prove hereafter a thing that will make Navigation commodious and that which moreover is of great moment in our businesse those Shelves of Mud which now discover themselves at the time of low-Low-Waters shall be alwayes covered so that the putrefaction of the Air shall also be remedied And lastly this abundance of Water being alwayes to discharge it self into the Sea by the Ports I do not doubt but that their bottomes will be scoured And that these effects must follow Nature her self seemeth to perswade there remaining onely one great doubt whether that abundance of Water that shall be brought into the Lake may be really sufficient to make the Waters rise so much as to keep the Shelves covered and to facilitate Navigation which ought to be at least half a Brace or thereabouts And indeed it seemeth at first sight to be impossible that the sole Water of the Brent let into the Lake and dispersed over the same can occasion so notable an height of water and the more to confirm the difficulties one might say reducing the reason to calculation that in case the Brent were 40. Braces broad and two and an half high and the breadth of the Lake were 20000. Braces it would seem necessary that the height of the water of the Brent dilated and distended thorow the Lake would be but onely 1 100 of a Brace in height which is imperceptible and would be of no avail to our purpose nay more it being very certain that the Brent runneth very muddy and foul this would occasion very great mischief filling and contracting the Lake and for that reason this remedy ought as pernicious to be totally excluded and condemned I here confesse that I am surprized at the forme of the Argument as if I were in a certain manner convinced that I dare not adventure to say more or open my mouth in this matter but the strength it self of the Argument as being founded upon the means of Geometrical and Arithmetical Calculation hath opened me the way to discover a very crafty fraud that is couched in the same Argument which fraud I will make out to any one that hath but any insight in Geometry and Arithmetick And as it is impossible that such an argument should be produced by any but such as have tasted of these in such affairs most profitable and most necessary Sciences so do not I pretend to make my self understood save onely by such to whom I will evince so clearly as that more it cannot be desired the errour and fraud wherein those Ancients and Moderns have been and alwayes are intangled that have in any way yet handled this matter of considering the Measure and Quantity of the Waters that move And so great is the esteem that I have for that which I am now about to say touching this particular that I am content that all the rest of my Discourse be rejected provided that that be perfectly understood which I am hereafter to propose I holding and knowing it to be a main Principle upon which all that is founded that can be said either well or handsomely on this particular The other Discourses may have an appearance of being probable but this hits the mark as full as can be desired arriving at the highest degree of certainty I have seventeen years since as I represented to the most Serene Prince and to the Right Honourable the President of the Lords the Commissioners of the Sewers written a Treatise of the Measure of the waters that move in which I Geometrically demonstrate and declare this businesse and they who shall have well understood the ground of my Discourse will rest fully satisfied with that which I am now about to propose But that all may become rhe more easie I will more briefly explicate and declare so much thereof as I have demonstrated in the Discourse which will suffice for our purpose And if that should not be enough we have alwayes the experiment
in equal times but that one of them should be four times more swift than the other the more slow should of necessity be four times more large And because the same River in any part thereof alwaies dischargeth the same quantity of Water in equal times as is demonstrated in the first Proposition of the first Book of the measure of Running Waters but yet doth not run thorowout with the same velocity Hence it is that the vulgar measures of the said River in divers parts of its Chanel are alwaies divers insomuch that if a River passing through its chanel had such velocity that it ran 100 Braces in the 1 1 60 of an hour-and afterwards the said River should be reduced to so much tardity of motion as that in the same time it should not run more than one Brace it would be necessary that that same River should become 100. times bigger in that place where it was retarded I mean 100. times bigger than it was in the place where it was swifter And let it be kept well in mind that this point rightly understood will clear the understanding to discover very many accidents worthy to be known But for this time let it suffice that we have onely declared that which makes for our purpose referring apprehensive and studious Wits to the perusal of my aforenamed Treatise for therein he shall finde profit and delight both together Now applying all to our principal intent I say That by what hath been declared it is manifest that if the Brent were 40. Braces broad and 2 1 2 high in some one part of its Chanel that afterwards the same Water of the Brent falling into the Lake and passing thorow the same to the Sea it should lose so much of its velocity that it should run but one Brace in the time wherein whilst it was in its Chanel at the place aforesaid it ran 100. Braces It would be absolutely necessary that increasing in measure it should become an hundred times thicker and therefore if we should suppose that the Lake were 20000. Braces the Brent that already hath been supposed in its Chanel 100. Braces being brought into the Lake should be 100. times 100. Brates that is shall be 10000. Braces in thickness and consequently shall be in height half a Brace that is 100 200 of a Brace and not 1â—â— 200 of a Brace as was concluded in the Argument Now one may see into what a gross errour of 99. in 100. one may fall through the not well understanding the true quantity of Running Water which being well understood doth open a direct way to our judging aright in this most considerable affair And therefore admitting that wich hath been demonstrated I say that I would if it did concern me greatly encline to consult upon the returning of the Brent again into the Lake For it being most evident that the Brent in the Chanel of its mouth is much swifter than the Brent being brought into the Lake it will certainly follow thereupon that the thickness of the Water of Brent in the Lake shall be so much greater than that of Brent in Brent by how much the Bront in Brent is swifter than thh Brent in the Lake 1. From which operation doth follow in the first place that the Lake being filled and increased by these Waters shall be more Navigable and passible than at present we see it to be 2. By the current of these Waters the Chanels will be scoured and will be kept clean from time to time 3. There will not appear at the times of low-waters so many Shelves and such heaps of Mud as do now appear 4. The Ayr will become more wholesom for that it shall not be so infected by putrid vapours exhaled by the Sun so long as the Miery Ouze shall be covered by the Waters 5. Lastly in the current of these advantagious Waters which must issue out of the Lake into the Sea besides those of the Tyde the Ports will be kept scoured and clear And this is as much as I shall offer for the present touching this weighty buisiness alwaies submitting my self to sounder judgements Of the above-said Writing I presented a Copy at Venice at a full Colledge in which I read it all and it was hearkned to with very great attention and at last I presented it to the Duke and left some Copies thereof with sundry Senators and went my way promising with all intenseness to apply my pains with reiterated studies in the publick service and if any other things should come into my minde I promised to declare them sincerely and so took leave of His serenity and that Noble Council When I was returned to Rome this business night and day continually running in my mind I hapned to think of another admirable and most important conceit which with effectual reasons confirmed by exact operations I with the Divine assistance made clear and manifest and though the thing at first sight seemed to me a most extravagant Paradox yet notwithstanding having satisfied my self of the whole business I sent it in writing to the most Illustrious and most Noble Signore Gio. Basadonna who after he had well considered my Paper carried it to the Council and after that those Lords had for many months maturely considered thereon they in the end resolved to suspend the execution of the diversion which they had before consulted to make of the River Sile and of four other Rivers which also fall into the Lake a thing by me blamed in this second Paper as most prejudicial and harmful The writing spake as followeth CONSIDERATIONS Concerning the LAKE OF VENICE CONSIDERATION II. IF the discoursing well about the truth of things Most Serene Prince were as the carrying of Burdens in which we see that an hundred Horses carry a greater weight than one Horse onely it would seem that one might make more account of the opinion of many men than of one alone But because that discoursing more resembleth running than carrying Burdens in which we see that one Barb alone runneth faster than an hundred heavy-heel'd Jades therefore I have ever more esteemed one Conclusion well managed and well considered by one understanding man although alone than the common and Vulgar opinions especially when they concern abstruce and arduous points Nay in such cases the opinions moulded and framed by the most ignorant and stupid Vulgar have been ever suspected by me as false for that it would be a great wonder if in difficult matters a common capacity should hit upon that which is handsom good and true Hence I have and do hold in very great veneration the summe of the Government of the most Serene and eternal Republick of Venice which although as being in nature a Common-wealth it ought to be governed by the greater part yet nevertheless in arduous affairs it is alwaies directed by the Grave Judgement of few and not judged blindly by the Plebeian Rout. T is true that he that propoundeth
Brent is very muddy and therefore if it should fall muddy into the Lake the Sand would sink and fill up the same Touching the first Query enough hath been said in my first Consideration where I have plainly discovered the deceipt of the Argument and shewn its fallacy It remaineth now to examine the second to which in the first place I say that one of the first things that I proposed in this affair was that I held it impossible to do any act though never so beneficial that was not also accompanied by some inconvenience and mischief and therefore we are to consider well the profit and the losse and prejudice and they both being weighed we shall be able to choose the lesser evil Secondly I admit it to be most true that Brent is at some times muddy but it is also true that for the greater part of the year it is not muddy Thirdly I do not see nor understand what strength this objection hath being taken so at large and in general and methinks that it is not enough to say that the Brent runneth muddy and to assert that it deposeth its Muddinesse in the Lake but we ought moreover to proceed to particulars and shew how much this Mud is and in what time this choaking up of the Ports may be effected For the Reasons are but too apparent and particular that conclude the ruine of the Lake and that in a very short time for mention is made of dayes the Waters diversion being made and moreover we have the circumstance of an Experiment the state of things being observed to have grown worse since the said diversion And I have demonstrated that in case the Diversion of the Sile and the other Rivers should be put in execution the Lake would in a few dayes become almost dry and the Ports would be lost with other mischievous consequences But on the other side although that we did grant the choaking of them we may very probably say that it will not happen save onely in the succession of many and many Centuries of years Nor can I think it prudent counsel to take a resolution and imbrace a Designe now to obtain a benefit very uncertain and more than that which only shall concern those who are to come very many Ages after us and thereby bring a certain inconvenience upon our selves and upon our children that are now alive and present Let it be alledged therefore although I hold it false that by the diversions of the Rivers the Lake may be kept in good condition for several years to come But I say confidently and hope to demonstrate it That the Diversions will bring the Lake even in our dayes to be almost dry and at least will leave so little water in it that it shall cease to be Navigable and the Ports shall most infallibly be choaked up I will therefore say upon experience in answer to this Objection that it is very necessary first well to discourse and rationally to particularize and ascertain the best that may be this point of the quantity of this sinking Mud or Sand. Now I fear I shall make my self ridiculous to those who measuring the things of Nature with the shallownesse of their brains do think that it is absolutely impossible to make this enquiry and will say unto me Quis mensus est pugillo aquas terram palmo ponderavit Yet nevertheless I will propound a way whereby at least in gross one may find out the same Take a Vessel of Cylindrical Figure holding two barrels of water or thereabouts and then fill it with the water of Brent at its Mouth or Fall into the Lake but in the Lake at the time that the Brent runneth muddy and after it hath begun to run muddy for eight or ten hours to give the mud time to go as far as S. Nicolo to issue into the Sea and at the same time take another Vessel like and equal to the first and fill it with the water of the Lake towards S. Nicolo but take notice that this operation ought to be made at the time when the waters go out and when the Sea is calm and then when the waters shall have setled in the aforesaid Vessels take out the clear water and consider the quantity of Sand that remains behind and let it be set down or kept in mind And I am easily induced to think that that shall be a greater quantity of Sand which shall be left in the first Vessel than that left in the second Vessel Afterwards when the Brent shall come to be clear let both the operations be repeated and observe the quantity of Sand in the aforesaid Vessels for if the Sand in the first Vessel should be most it would be a sign that in the revolution of a year the Brent would depose Sand in the Lake And in this manner one may calculate to a small matter what proportion the Sand that entreth into the Lake hath to that which remains And by that proportion one may judge how expedient it shall be for publick benefit And if at several times of the year you carefully repeat the same operations or rather observations you would come to a more exact knowledge in this business And it would be good to make the said operations at those times when the Lake is disturbed by strong high Winds and made muddy by its own Mud raised by the commotion of the Waters This notion would give us great light if the same observations should be made towards the Mouth of Lio at such time as the waters flow and ebb in calm seasons for so one should come to know whether the waters of the Lake are more thick at the going out than at the entrance I have propounded the foregoing way of measuring Sands and Mud to shew that we are not so generally and inconsiderately to pronounce any sentence but proceed to stricter inquiries and then deliberate what shall be most expedient to be done Others may propose more exquisite examinations but this shall serve me for the present I will add onely that if any one had greater curiosity it would be profitable to have it in investigating more exactly the quantity of the Water that entereth into the Lake by the means that I have shewen in the beginning of this Book When he shall have found the proportion of the quantity of water to the quantity of Sand or Mud he shall come to know how much Sand the Brent shall leave in the Lake in the space of a year But to perform these things there are required persons of discretion and fidelity and that are imployed by publick Order for there would thence result eminent benefit and profit Here are wanting LETTERS from several persons To the Reverend Father Francesco di S. GIUSEPPE IN execution of the command that you laid upon me in your former Letters by order from the most Serene my Lord Prince Leopold that I should speak my judgement concerning the disimboguement of
the River called Fiume morto whether it ought to be let into the Sea or into Serchio I say that I chanced 18. years since to be present when the said Mouth was opened into the Sea and that of Serchio stopt which work was done to remedy the great Innundation that was made in all that Country and Plain of Pisa that lyeth between the River Arno and the Mountains of S. Giuliano and the River Serchio which Plain continued long under water insomuch that not onely in the Winter but also for a great part of the Summer those fields were overflowed and when that the Mouth of Fiume morto was effectually opened into the Sea the place was presently freed from the waters and drained to the great satisfaction of the Owners of those Grounds And here I judge it worth your notice that for the generality of those that possess estates in those parts they desired that the Mouth of Fiume morto might stand open to the Sea and those who would have it open into Serchio are persons that have no other concernment there save the hopes of gaining by having the dispose of Commissions and the like c But for the more plain understanding of that which is to be said it must be known That the resolution of opening the said Mouth into Serchio was taken in the time of the Great Duke Ferdinando the first upon the same motives that are at this time again proposed as your Letters tell me Since that it manifestly appearing that Fiume morto had and hath its Mouth open to the Sea the Plain hath been kept dry and it being also true that the fury of the South and South-West-Winds carryed such abundance of sand into the Mouth or Out-let of Fiume morto that it wholly stopt it up especially when the waters on Pisa side were low and shallow And they think that turning the Lake of Fiume morto into Serchio and the Serchio maintaining continually its own Mouth with the force of its waters open to the Sea and consequently also Fiume morto they would have had the Out-let clear and open and in this manner they think that the Plain of Pisa would have been freed from the waters The business passeth for current at first sight but experience proveth the contrary and Reason confirmeth the same For the height of the water of those Plains was regulated by the height of the waters in the Mouth of Fiume morto that is The waters at the Mouth being high the waters also do rise in the fields and when the waters at the Mouth are low the waters of the fields do likewise abate Nor is it enough to say That the Out-let or Vent of Fiume morto is continual but it must be very low Now if Fiume morto did determine in Serchio it is manifest that it would determine high for Serchio terminating in the Sea when ever it more and more aboundeth with water and riseth it is necessary that also Fiume morto hath its level higher and consequently shall keep the waters in the Plains higher Nay it hath happened sometimes and I speak it upon my own sight that Fiume morto hath reversed its course upwards towards Pisa which case will ever happen whensoever the Pisan waters chance to be lower than the level of those of Serchio for in that case the waters of Serchio return back upon the Plains thorow Fiume morto in such sort that the Muddinesses and the Serchio have been observed to be carried by this return as farr as the Walls of Pisa and then before such time as so great waters can be asswaged which come in with great fury and go out by little and little there do pass very many days and moneths nay sometimes one being never able to find the waters of Serchio when at the shallowest so low as the Sea in level which is the lowest place of the waters it thence doth follow that the waters of Fiume morto should never at any time of the year so long as they determine in Serchio be so low as they come to be when the same Fiume morto determineth in the Sea T is true indeed that the Mouth of Fiume morto opened into the Sea is subject to the inconvenience of being stopt up by the force of Winds But in this case it is necessary to take some pains in opening it which may easily be done by cutting that Sand a little which stayeth in the Mouth after that the Wind is laid and it is enough if you make a Trench little more than two Palms in breadth for the water once beginning to run into it it will in a few hours carry that Sand away with it and there will ensue a deep and broad Trench that will drain away all the water of the Plains in very little time And I have found by practice that there having been a great quantity of Sand driven back by the fury of the South-West-Wind into the Mouth of Fiume morto I having caused the little gutter to be made in the Morning somewhat before Noon a Mouth hath been opened of 40. Braces wide and notably deep insomuch that the water which before had incommoded all the Champian ran away in less than three dayes and left the Country free and dry to the admiration of all men There was present upon the place at this business on the same day that I opened the Mouth the most Serene great Duke the most Serene Arch-Dutchess Mother all the Commissioners of Sewers with many other Persons and Peasants of those parts and they all saw very well that it was never possible that a little Bark of eight Oars which was come from Legorn to wait upon the great Duke should ever be able to master the Current and to make up into Fiume morto and his Highness who came with an intent to cause the said Mouth towards the Sea to be stopt and that into Serchio to be opened changed his judgement giving order that it should be left open towards the Sea as it was done And if at this day it shall return into Serchio I am very certain that it will be necessary to open it again into the Sea And there was also charge and order given to a person appointed for the purpose that he should take care to open the said Mouth as hath been said upon occasion And thus things have succeeded very well unto this very time But from the middle of October until this first of February there having continued high South and South-West-Winds with frequent and abundant Rains it is no wonder that some innundation hath happened but yet I will affirm that greater mischiefs would have followed if the Mouth had been opened into Serchio This which I have hitherto said is very clear and intelligible to all such as have but competent insight and indifferent skill in these affairs But that which I am now about to propose farther will I am very certain be understood by your self but it will seem
strange and unlikely to many others The point is that I say That by raising the level of Fiume morto one half Brace onely at its Mouth it will penipenitrate into Serchio farther than it would into the Sea it shall cause the waters to rise three or perhaps more Braces upon the fields towards Pisa and still more by degrees as they shall recede farther from the Sea-side and thus there will follow very great Innundations and considerable mischiefs And to know that this is true you are to take notice of an accident which I give warning of in my discourse of the Measure of Running Waters where also I give the reason thereof Coroll 14. The accident is this That there coming a Land-Flood for example into Arno which maketh it to rise above its ordinary Mouth within Pisa or a little above or below the City six or seven Braces this same height becometh alwaies lesser and lesser the more we approach towards the Sea-side insomuch that near to the Sea the said River shall be raised hardly half a Brace Whence it followeth of necessary consequence that should I again be at the Sea-side and knowing nothing of what hapneth should see the River Arno raised by the accession of a Land-flood one third of a Brace I could certainly infer that the same River was raised in Pisa those same six or seven Braces And that which I say of Arno is true of all Rivers that fall into the Sea Which thing being true it is necessary to make great account of every small rising that Fiume morto maketh towards the Sea-side by falling into Serchio For although the rising of Fiume morto by being to disgorge its Waters into Serchio towards the Sea were onely a quarter of a Brace we might very well be sure that farr from the Sea about Pisa and upon those fields the rise shall be much greater and shall become two or three Braces And because the Countrey lyeth low that same â—ise will cause a continual Innundation of the Plains like as it did before I caused the Mouth to be opened into the Sea And therefore I conclude that the Mouth of Fiume morto ought by no means to be opened into Serchio but ought to be continued into the Sea using all diligence to keep it open after the manner aforesaid so soon as ever the Wind shall be laid And if they shall do otherwise I confidently affirm that there will daily follow greater damages not onely in the Plains but also in the wholesomness of the Air as hath been seen in times past And again It ought with all care to be procured that no waters do by any means run or fall from the Trench of Libra into the Plain of Pisa for these Waters being to discharge into Fiume morto they maintain it much higher than is imagined according to that which I have demonstrated in my consideration upon the state of the Lake of Venice I have said but little but I speak to you who understandeth much and I submit all to the most refined judgment of our most Serene Prince Leopold whose hands I beseech you in all humility to kiss in my name and implore the continuance of his Princely favour to me and so desiring your prayers to God for me I take my leave Rome 1. Feb. 1642. Your most affectionate Servant D. BENEDETTO CASTELLI The answer to a Letter written by BARTOLOTTI touching the difficultyes observed The former part of the Letter is omitted and the discourse beginneth at the first Head ANd first I say Whereas I suppose that the level of the Serchio is higher than that of Fiume morto this is most true at such time as the waters of Fiume morto are discharged into the Sea but I did never say that things could never be brought to that pass as that the level of Fiume morto should be higher than Serchio and so I grant that it will follow that the waters of Fiume morto shall go into Serchio and it s very possible that the Drain of Fiume morto into Serchio may be continuate and I farther grant that its possible that the Serchio doth never disgorge thorow Fiume morto towards Pisa Nay I will yet farther grant that it might have happened that Fiume morto might have had such a fall into Serchio as would have sufficed to have turned Mills But then I add withall that the Plains of Pisa and the City it self must be a meer Lake 2. Signore Bartolotti saith confidently that when the Sea swelleth by the South-West or other Winds the level of Serchio in the place marked A in the Platt distant about 200. Braces riseth very little But that Fiume morto in D and in E many miles more up into Land riseth very much and that certain Fishermen confirm this and shew him the signes of the rising of the Water I grant it to be very true and I have seen it with my own eyes But this cometh to pass when the Mouth of Fiume morto is stopt up by the Sea as I shall shew by and by And this rising near the Sea-side is of no considerable prejudice to the fields And this is as much as I find to be true in the assertion of Signore Bartolotti without his confirming it by any other proof as indeed it needs none That the level of Fiume morto riseth in E and many miles farther upwards it riseth much nor did I ever affirm the contrary 3. Concerning the difficulty of opening the Mouth of Fiume morto into the Sea that which Il Castellano saith is most certain namely That at the entrance upon the opening of the Mouth it is necessary to make a deep Trench But I say that at that time it is difficult to open it unless upon great occasions for that the difficulty proceedeth from the waters of Fiume morto being low and the fields drained 4. As to the particular of the Causes that you tell me men press so much unto the most Serene Grand Duke and to the Prince I have not much to say because it is not my profession nor have I considered of the same Yet I believe that when the Prince and his Highnesse see the benefit of his People and Subjects in one scale of the Ballance and the accomodation of Huntsmen in the other his Highnesse will incline to the profit of his subjects such have I alwayes found his Clemency and Noblenesse of minde But if I were to put in my vote upon this businesse I would say that the points of Spears and the mouths of Guns the yelping of Dogs the wilynesse of Huntsmen who run thorow and narrowly search all those Woods Thickets and Heathes are the true destroyers of Bucks and Boares and not a little Salt-water which setleth at last in some low places and spreadeth not very far Yet neverthelesse I will not enter upon any such point but confine my self solely to the businesse before me 5. That Experiment of joyning together the water
of Fiume morto and that of Serchio by a little trench to see what advantage the Level E hath upon the Level I doth not give me full satisfaction taken so particularly for it may come to passe that sometimes E may be higher and sometimes A lower and I do not question but that when Serchio is low and Fiume morto full of Water the level of Fiume morto will be higher than that of Serchio But Serchio being full and Fiume morto scant of Water the contrary will follow if the Mouth shall be opened to the Sea And here it should seem to me that it ought to be considered that there is as much advantage from E to the Sea through the little Trench opened anew into Serchio as from E to the Sea by the Mouth of Fiume morto But the difficulty which is that we are to regard in our case is that the course of the Waters thorow the Trench is three times longer than the course of the Mouth of Fiume morto as appeareth by the Draught or Plat which you sent me which I know to be very exactly drawn for that the situation of those places are fresh in my memory Here I must give notice that the waters of Fiume morto determining thorow the Trench in Serchio the waters of which Fiume morto are for certain never so low as the Sea their pendency or declivity shall for two causes be lesse than the pendency of those waters through the Mouth towards the Sea that is because of the length of the line through the Trench and because of the height of their entrance into Serchio a thing which is of very great import in discharging the waters which come suddenly as he shall plainly see who shall have understood my Book of the Measure of Running Waters And this was the Reason why all the Countrey did grow dry upon the opening of the Mouth into the Sea And here I propose to consideration that which the Peasants about Pisa relate namely That the Water in the Fields doth no considerable harm by continuing there five or six yea or eight dayes And therefore the work of the Countrey is to open the Mouth of Fiume morto in such manner that the Water being come they may have the Trench free and ready when that the Water cometh it may have a free drain and may not stay there above eight or nine dayes for then the overflowings become hurtful It is to be desired also that if any Proposition is produced touching these affairs it might be propounded the most distinctly that may be possible and not consist in generals especially when the Dispute is of the risings of velocity of tardity of much and little water things that are all to be specified by measures 6. Your Letter saith in the next place that Signore Bartolotti confesseth that if the Mouth of the Fiume morto might alwayes be kept open it would be better to let it continue as it is the which that I may not yield to him in courtesie I confesse for the keeping it stopt on all sides would be a thing most pernicious But admitting of his confession I again reply that Fiume morto ought not to be let into Serchio but immediately into the Sea because although sometimes the Mouth to seawards be stopt up yet for all that the raising of the Bank above the Plains which is all the businesse of importance shall be ever lesser if we make use of the Mouth leading to the Sea than using that of Serchio 7. I will not omit to mention a kinde of scruple that I have concerning the position of Sign Bartolotti that is where he saith that the two Mouths A and D are equal to the like Mouths into the Sea Now it seems to me that the Mouth A of Fiume morto into Serchio is absolutely within Serchio nor can it be made lower and is regulated by the height of Serchio But the Mouth of Fiume morto terminates and ought to be understood to terminate in the Sea it self the lowest place And this I believe was very well perceived by Sig. Bartolotti but I cannot tell why he past it over without declaring it and we see not that the Mouth D falleth far from the Sea which Mouth ought to be let into the Sea it self and so the advantage of the Mouth into the Sea more clearly appeareth 8. That which Sig. Bartolotti addeth that when it is high Waters at such time as the Waters are out and when Winds choak up Fiume morto they not only retard it but return the course of the Waters upwards very leasurely perswadeth me more readily to believe that Sig. Bartolotti knoweth very well that the Mouth of Fiume morto let into Serchio is hurtful for by this he acknowledgeth that the Mouth towards the Sea doth in such sort drain the Countrey of the Waters as that they become very low and therefore upon every little impetus the waters turn their course And from the motions being exceeding slow is inferred that the abundance of Sea-water that cometh into Fiume morto is so much as is believed and as Sig. Bartolotti affirmeth 9. After that Sig. Bartolotti hath said what he promiseth above namely that when the Windes blowing strongly do stop up Fiume morto and not onely retard but turn the course upwards the time being Rainy and the Mouth of Fiume morto shut up the Waves of the Sea passe over the Bank of Fiume morto at that time saith Signore Bartolotti the Champain shall know the benefit of Fiume morto discharged into Serchio and the mouth A shall stand alwayes open and Fiume morto may alwayes constantly run out as also the Rains and Rain-waters although the hurtful Tempest should last many dayes c. And I reply that all the Art consists in this for the benefit of those Fields doth not depend on or consist in saying that Fiume morto is alwayes open and Fiume morto draineth continually But all the businesse of profit lyeth and consisteth in maintaining the Waters low in those Plaines and those Ditches which shall never be effected whilst the World stands if you let Fiume morto into Serchio but yet it may by opening the mouth into the Sea and so much reason and nature proveth and which importeth Experience confirmeth 10. In the tenth place I come to consider the answer that was made to another Proposition in the Letter which I writ to Father Francesco which prudently of it self alone might serve to clear this whole businesse I said in my Letter That great account is to be made of every small rising and ebbing of the Waters neer to the Sea in Fiume morto for that these risings and fallings although that they be small neer to the Sea-side yet neverthelesse they operate and are accompanied by notable risings and fallings within Land and far from the Sea-side and I have declared by an example of Arno in which a Land-flood falling that made it increase above its ordinary
height within Pisa six or seven Braces that this height of the same Flood becometh still lesser the neerer we approach to the Sea-coasts Nor shall the said River be raised hardly half a Brace whereupon it necessrily followeth that if I should return to the Sea-side and not knowing any think of that which happeneth at Pisa and seeing the River Arno raised by a Land-flood half a Brace I might confidently affirm the said River to be raised in Pisa those six or seven Braces c. From such like accidents I conclude in the same Letter that it is necessary to make great account of every little rise that Fiume morto shall make towards the Sea Now cometh Bartolotti and perhaps because I knew not how to express my self better understandeth not my Proposition and speaketh that which indeed is true but yet besides our case Nor have I ever said the contrary and withall doth not apply it to his purpose Nay I say that if he had well applyed it this alone had been able to have made him change his opinion And because he saith that I said that it is true when the abatement proceedeth from some cause above as namely by Rain or opening of Lakes But when the cause is from below that is by some stop as for instance some Fishers Wears or Locks or some impediment remote from the Sea although at the Level it shall rise some Braces where the impediment is yet that rising shall go upwards and here he finisheth his Discourse and concludeth not any thing more To which I say first that I have also said the same in the Proposition namely that a Flood coming which maketh Arno to rise in Pisa six or seven Braces which I take to be a superiour cause whether it be Rain or the opening of Lakes as best pleaseth Bartolotti in such a case I say and in no other for towards the Sea-coasts it shall not cause a rising of full half a Brace and therefore seeing Arno at the Sea-side to be raised by a Flood whether of Rain or of opening of Lakes half a Brace it may be inferred that at Pisa it shall be raised those six or seven Braces which variety well considered explaineth all this affair in favour of my opinion For the rising that is made by the impediment placed below of Fishing Weares and Locks operateth at the beginning raising the Waters that are neer to the impediment and afterwards less and less as we retire upwards from the impediment provided yet that we speak not of a Flood that commeth by accession but onely of the ordinary Water impeded But there being a new accession as in our case then the Water of the Flood I say shall make a greater rising in the parts superiour far from the impediment and these impediments shall come to be those that shall overflow the Plains as happened eighteen or nineteen years ago before the opening of Fiume morto into the Sea The same will certainly follow if Fiume morto be let into Serchio Here I could alledge a very pretty case that befell me in la Campagna di Roma neer to the Sea-side where I drained a Bog or Fen of the nature of the Waters of Pisa and I succeeded in the enterprize the Waters in their site towards the Sea abating only three Palmes and yet in the Fen they fell more than fifteen Palmes But the businesse would be long and not so easily to be declared and I am certain that Sig. Bartolotti having considered this would alter his judgment and withall would know that remitting that impediment anew which I had left for lesse than three â—almes towards the Sea the Waters in the Fen would return with the first Floods and Raines to the same height as before as likewise Fiume morto will do if it shall be let again into Serchio Here I intreat your Honour to do me the favour to importune P. Francesco in my behalf that he would be pleased to deelare my meaning in the aforesaid Letter to Sig. Bartolotti for I hope that if he will understand this point he will be no longer so tenacious in his opinion Next that these Lords in the Commission of Sewers with the Right Honourable the Marquesse of S. Angelo and your Honour do approve of my judgment doth very much rejoyce me but because that I know that they do it not in design to complement me but onely to serve his Highness our Grand Duke I freely profess that I will pretend no farther obligations from them therein than I account my self to owe to those whose opinions are contrary to mine for that I know that they have the same end The definitive sentence of this whole business is that they give these Plains these Draines and these Waters farre fetcht appellations 11. As to the quantity of the Water that Fiume morto dischargeth into the Sea there are very great disputes about it and I have been present at some of them But let your Honour believe me that as this is not continual but only during a few dayes so it will never be of any great prejudice to these Fields and if your Lordship would be ascertained thereof you may please to go to Fiume morto at about a mile's distance from the Sea in the time of these strong Windes and observe the current from thence upwards for you shall finde it extream slow and consequently will know that the quantity of the Water that is repuls'd is very small And this seems to be contradicted by the rule of Risings proceeding from causes below which occasion no considerable alteration far from the Sea I am necessitated to go to morrow out of Rome with his Eminence Cardinal Gaetano about certain affairs touching Waters therefore I shall not farther inlarge but for a close to this tedious Discourse I conclude in few words that Fiume morto is by no means to be let into Serchio nor are there any means intermediate courses to be taken for they will alwayes be prejudicial but Fiume morto is to be discharged immediately into the Sea When it is stopt up by the fury of the Sea-waves I affirm that it is a sign that there is no need of opening it and if there be any occasion to open it it is easily done As for the rest your Lordship may please to keep account of all the particulars that occur for the memory of things past is our Tutresse in those that are to come If occasion shall offer I intreat you to bow humbly in my name to His Highness the Grand Duke and the most Serene Prince Leopold and to attend the service of Their Highnesses for you serve â—rinces of extraordinary merit And to whom I my self am also exceedingly obliged In the controversies that arise respect the pious end of speaking the Truth for then every thing will succeed happily I kiss the hands of Padre Francesco of Sig. Bartolotti and of your Lordship Rome 14. March 1642. Your Honours most Obliged
distend for to this instance we answer with that which we have given notice of in the First Consideration touching the Lake of Venice treating of the abatement that is caused by the Brent let into the Lake And moreover if I shall adde thereto that which I write in the Second Consideration it will be very apparent how greatly harmfull and prejudicial these excursions of Waters from Fiume Sisto may be which are not kept under and confined within the River Therefore proceeding to the provisions and operations that are to be accounted Principall I reduce them to three Heads In the first place it is necessary to throw down those Weares and to take the Pisciaries quite away observing a Maxime in my judgment infallible that Fishing and Sowing are two things that can never consist together Fishing being on the Water and Sowing on land Secondly it will be necessary to cut under Water in the bottome of the River those Weeds and Plants that grow and increase in the River and leave them to be carried into the Sea by the Stream for by this means these Reeds shall not spring up and distend along the bottome of the River by means of the Beasts treading upon them And the same ought to be done often and with care and must not be delaied till the mischief increase and the Champain Grounds be drowned but one ought to order matters so as that they may not drown And I will affirm that otherwise this principal point would become a most considerable inconvenience Thirdly it is necessary to make good the Banks of Fiume Sisto on the left hand and to procure that those Waters may run in the Chanel and not break forth And it is to be noted that it is not enough to do one or two of those things but we are to put them all in execution for omitting any thing the whole machine will be out of tune and spoiled But proceeding with due care you shall not only Drain the Pontine Fens but by means of this last particular the Current of Fiume Sisto shall scowr its own Chanel of its self even to the carrying part of it away and haply with this abundance of water that it shall bear the Mouth della Torre may be opened and kept open into the Sea And it would last of all be of admirable benefit to cleanse Fiume Sisto from many Trees and Bushes wherewith it is overgrown And with this I conclude that the Improvement or Drain possible to be made consisteth in these three particulars First in taking away the Fishing Weares leaving the Course of the Waters free Secondly in keeping the Principal Rivers clear from Weeds and Plants Thirdly in keeping the water of Fiume Sisto in its own Chanel All which are things that may be done with very little charge and to the manifest benefit of the whole Country and to the rendering the Air wholsomer in all those Places adjoyning to the Pontine Fens A CONSIDERATION Upon the DRAINING Of the Territories of Bologna Ferrara AND Romagna BY D. BENEDETTO CASTELLI Abbot of S. BENEDETTO ALOISIO Mathematician to P. Vrban VIII and Professor in the University of ROME THe weghty businesse of the Draining of the Territories of Bologna Ferrara and Romagna having been punctually handled and declared in writing from the excellent memory of the Right Honourable and Noble Monsignore Corsini who was heretofore Deputed Commissary General and Visitor of those Waters I am not able to make such another Discourse upon the same Subject but will only say somewhat for farther confirmation of that which I have said in this Book upon the Lake of Venice upon the Pontine Fens and upon the Draining of those Plains of Pisa lying between the Rivers Arno and Serchio whereby it is manifest that in all the aforementioned Cases and in the present one that we are in hand with there have in times past very grosse Errours been committed through the not having ever well understood the true measure of Running waters and here it is to be noted that the businesse is that in Venice the diversion of the waters of the Lake by diverting the Brent was debated and in part executed without consideration had how great abatement of water might follow iâ— the Lake if the Brent were diverted as I have shewn in the first Consideration upon this particular from which act there hath insued very bad consequences not only the difficulty of Navigation but it hath infected the wholsomnesse of the Air and caused the stoppage of the Ports of Venice And on the contrary the same inadvertency of not considering what rising of the Water the Reno and other Rivers being opened into the Valleys of Bologna and Ferrara might cause in the said Valleys is the certain cause that so many rich and fertile Fields are drowned under water converting the happy habitations and dwellings of men into miserable receptacles for Fishes Things which doubtlesse would never have happened if those Rivers had been kept at their height and Reno had been turn'd into Main-Po and the other Rivers into that of Argenta and of Volano Now there having sufficient been spoken by the above-named Monsig Corsini in his Relation I will only adde one conceit of my own which after the Rivers should be regulated as hath been said I verily believe would be of extraordinary profit I much doubt indeed that I shall finde it a hard matter to perswade men to be of my mind but yet nevertheless I will not question but that those at least who shall have understood what I have said and demonstrated concerning the manners and proportions according to which the abatements and risings of Running waters proceed that are made by the Diversions and Introductions of VVaters will apprehend that my conjecture is grounded upon Reason And although I descend not to the exactnesse of particulars I will open the way to others who having observed the requisite Rules of considering the quantity of the waters that are introduced or that happen to be diverted shall be able with punctuality to examine the whole businesse and then resolve on that which shall be expedient to be done Reflecting therefore upon the first Proposition that the Risings of a Running Water made by the accession of new water into the River are to one another as the Square-Roots of the quantity of the water that runneth and consequently that the same cometh to pass in the Diversions Insomuch that a River running in height one such a certain measure to make it encrease double in height the water is to be encreased to three times as much as it ran before so that when the water shall be quadruple the height shall be double and if the water were centuple the height would be decuple onely and so from one quantity to another And on the contrary in the Diversions If of the 100. parts of water that run thorow a River there shall be diverted 19 1â—â— the height of the River diminisheth onely 1 10
and continuing to divert 17 100 the height of the River abateth likewise 1 10 and so proceeding to divert 15 100 and then 13 100 and then 11 100 and then 9 100 and then 7 100 and then 5 100 and then 3 106 alwaies by each of these diversions the height of the Running Water diminisheth the tenth part although that the diversions be so unequal Reflecting I say upon this infallible Truth I have had a conceit that though the Reno and other Rivers were diverted from the Valleyes and there was onely left the Chanel of Navigation which was onely the 1 20 part of the whole water that falleth into the Valleys yet nevertheless the water in those same Valleyes would retain a tenth part of that height that became conjoyned by the concourse of all the Rivers And therefore I should think that it were the best resolution to maintain the Chanel of Navigation if it were possible continuate unto the Po of Ferrara and from thence to carry it into the Po of Volano for besides that it would be of very great ease in the Navigation of Bologna and Ferrara the said water would render the Po of Volano navigable as far as to the very Walls of Ferrara and consequently the Navigation would be continuate from Bologna to the Sea-side But to manage this enterprize well it is necessary to measure the quantity of the Water that the Rivers discharge into the Valleys and that which the Chanel of Navigation carryeth in manner as I have demonstrated at the beginning of this Book for this once known we shall also come to know how profitable this diversion of the Chanel of Navigation from the Valleys is like to prove which yet would still be unprofitable if so be that all the Rivers that discharge their waters into the Valleys should not first be Drained according to what hath been above advertised Abbot CASTELLI in the present consideration referring himself to the Relation of Monsig Corsini grounded upon the Observations and Precepts of the said Abbot as is seen in the present Discourse I thought it convenient for the compleating of the Work of our Authour upon these subjects to insert it in this place A Relation of the Waters in the Territories of Bologna and Ferrara BY The Right Honourable and Illustrious Monsignore CORSINI a Native of Tuscany Superintendent of the general DRAINS and President of Romagna THe Rheno and other Brooks of Romagna were by the advice of P. Agostino Spernazzati the Jesuite towards the latter end of the time of Pope Clement VIII notwithstanding the opposition of the Bolognesi and others concerned therein diverted from their Chanels for the more commodious cleansing of the Po of Ferrara and of its two Branches of Primaro and Volano in order to the introducing the water of the Main-Po into them to the end that their wonted Torrents being restored they might carry the muddy-Muddy-water thence into the Sea and restore to the City the Navigation which was last as is manifest by the Brief of the said Pope Clement directed to the Cardinal San Clemence bearing date the 22. of August 1604. The work of the said cleansing and introducing of the said Po either as being such in it self or by the contention of the Cardinal Legates then in these parts and the jarrings that hapned betwixt them proved so difficult that after the expence of vast summs in the space of 21. years there hath been nothing done save the rendring of it the more difficult to be effected Interim the Torrents with their waters both muddy and clear have damaged the Grounds lying on the right hand of the Po of Argenta and the Rheno those on its Banks of which I will speak in the first place as of that which is of greater importance and from which the principal cause of the mischiefs that result from the rest doth proceed This Rheno having overflowed the Tennency of Sanmartina in circumference about fourteen miles given it before and part of that of Cominale given it afterwards as it were for a receptacle from whence having deposed the matter of its muddiness it issued clear by the Mouths of Masi and of Lievaloro into the Po of Primaro and of Volano did break down the encompassing Bank or Dam towards S. Martino and that of its new Chanel on the right hand neer to Torre del Fondo By the breaches on this side it streamed out in great abundance from the upper part of Cominale and in the parts about Raveda Pioggio Caprara Ghiare di Reno Sant ' Agostino San Prospero San Vincenzo and others and made them to become incultivable it made also those places above but little fruitful by reason of the impediments that their Draines received finding the Conveyances called Riolo and Scorsuro not only filled by la Motta and la Belletta but that they turned backwards of themselves But by the Mouths in the inclosing Bank or Dam at Borgo di S. Martino issuing with violence it first gave obstruction to the ancient Navigation of la Torre della Fossa and afterwards to the moderne of the mouth of Masi so that at present the Commerce between Bologna and Ferrara is lost nor can it ever be in any durable way renewed whilst that this exceeds its due bounds and what ever moneys shall be imployed about the same shall be without any equivalent benefit and to the manifest and notable prejudice of the Apostolick Chamber Thence passing into the Valley of Marzara it swelleth higher not only by the rising of the water but by the raising of the bottome by reason of the matter sunk thither after Land-floods and dilateth so that it covereth all the Meadows thereabouts nor doth it receive with the wonted facility the Drains of the upper Grounds of which the next unto it lying under the waters that return upwards by the Conveyances and the more remote not finding a passage for Rain-waters that settle become either altogether unprofitable or little better From this Valley by the Trench or Ditch of Marzara or of la Duca by la Buova or mouth of Castaldo de Rossi and by the new passage it falleth into the Po of Argenta which being to receive it clear that so it may sink farther therein and receiving it muddy because it hath acquired a quicker course there will arise a very contrary effect Here therefore the superficies of the water keeping high until it come to the Sea hindereth the Valleys of Ravenna where the River Senio those of San Bernardino where Santerno was turned those of Buon ' acquisto and those of Marmorto where the Idice Quaderna Sellero fall in from swallowing and taking in their Waters by their usual In-lets yet many times as I my self have seen in the Visitation they drink them up plentifully whereupon being conjoyned with the muddinesse of those Rivers that fall into the same they swell and dilate and overflow some grounds and deprive others of their Drains in like manner
Giorgio and the Valleys of Comachio by the waters that should enter into the Goro or Dam of the Mills of Belriguardo thorow the Trenches of Quadrea which cannot be stopt because they belong to the Duke of Modena who hath right of diverting the waters of that place at his pleasure to the work of turning Mills The greater part of which Objections others pretend to prove frivolous by saying that its running there till at the last it was turned another way is a sign that it had made such an elevation of the Line of its Bed as it required denying that it needeth so great a declivity as is mentioned above and that for the future it would rise no more That the said Draâ—ns and Ditches did empty into the same whilst Po was there so that they must needs be more able to do so when onely Reno runs that way That there would no Breaches follow or if they did they would be onely of the water of Reno which in few hours might be taken away in those parts they call damming up of Breaches and mending the Bank taking away the Breaches and it s a question whether they would procure more inconvenience than benefit for that its Mud and Sand might in many places by filling them up occasion a seasonable improvement Now omitting to discourse of the solidity of the reasons on the oneside or on the other I will produce those that move me to suspend my allowance of this design The first is that although I dare not subscribe to the opinion of those that require 16. inches Declivity in a mile to Reno to prevent its deposing of Mud yet would I not be the Author that should make a trial of it with so much hazard for having to satisfie my self in some particulars caused a Level to be taken of the Rivers L'amone Senio and Santerno by Bernardino Aleotti we found that they have more Declivity by much than Artists require as also the Reno hath from la Botta de Ghislieri to the Chappel of Vigarano for in the space of four miles its Bottom-Line falleth five feet and five inches So that I hold it greater prudence to depend upon that example than to go contrary to a common opinion especially since that the effects caused by Reno it self do confirm me in the same for when it was forsaken by the Po after a few years either because it had choaked up its Chanel with Sand or because it s too long journey did increase it it also naturally turned aside and took the way of the said Po towards Stellata Nay in those very years that it did run that way it only began as relations say to make Breaches an evident sign that it doth depose Sand and raise its Bed which agreeth with the testimony of some that were examined in the Visitation of the Publique Notary who found great benefit by having Running Water and some kind of passage for Boats and yet nevertheless affirm that it for want of Running Water had made too high Stoppages and Shelfes of Sand so that if it should be restored to the Course that it forsook I much fear that after a short time if not suddenly it would leave it a-again The second I take from the observation of what happened to Panaro when with so great applause of the Feraresi it was brought by Cardinal Serra into the said Chanel of Volana for that notwithstanding that it had Running Waters in much greater abundance than Reno yet in the time that it continued in that Chanel it raised its Bed well neer five feet as is to be seen below the Sluice made by Cardinal Capponi to his new Chanel yea the said Cardinal Serra who desired that this his undertaking should appear to have been of no danger nor damage was constrained at its Overflowings to give it Vent into Sanmartina that it might not break in upon and prejudice the City which danger I should more fear from Reno in regard it carrieth a greater abundance of Water and Sand. Thirdly I am much troubled in the uncertainty of the success of the affair at the great expence thereto required For in regard I do not approve of letting it in neer to the Fortresse for many respects and carrying it by la Torre del Fondo to the Mouth de Masi it will take up eight miles of double Banks a thing not easie to be procured by reason that the Grounds lie under Water but from the Mouth de Masi unto Codigoro it would also be necessary to make new Scowrings of the Chanel to the end that the Water approaching by wearing and carrying away the Earth on both shores might make a Bed sufficient for its Body the depth made for Panaro not serving the turn as I conceive and if it should suffice when could the people of Ferrara hope to be re-imbursed and satisfied for the charge thereof Fourthly it serves as an Argument with me to see that the very individual persons concerned in the Remotion or Diversion of the said Torrent namely the Bolognesi do not incline unto it and that the whole City of Ferrara even those very persons who at present receive damage by it cannot indure to hear thereof The reason that induceth these last named to be so averse thereto is either because that this undertaking will render the introduction of the Water of Main-Po more difficult or because they fear the danger thereof The others decline the Project either for that they know that Reno cannot long continue in that Course or because they fear that it is too much exposed to those mens revengeful Cutting of it who do not desire it should and if a man have any other wayes he ought in my opinion to forbear that which to such as stand in need of its Removal is lesse satisfactory and to such as oppose it more prejudicial To conclude I exceedingly honour the judgment of Cardinal Capponi who having to his Natural Ability and Prudence added a particular Study Observation and Experience of these Waters for the space of three years together doth not think that Reno can go by Volana to which agreeth the opinion of Cardinal S. Marcello Legate of this City of whom for his exquisite understanding we ought to make great account But if ever this should be resolved on it would be materially necessary to unite the Quick and Running Waters of the little Chanel of Cento of the Chanel Navilio of Guazzaloca and at its very beginning those of Dardagna which at present is one of the Springs or Heads of Panaro that so they might assist it in carrying its Sand and the matter of its Muddiness into the Sea and then there would not fail to be a greater evacuation and scowring but withall the Proprietors in the Islet of San Giorgio and of Ferrara must prepare themselves to indure the inconveniences of Purlings or Sewings of the Water from the River thorow the Boggy Ground thereabouts I should more easily incline therefore
to carry it into Main-Po at Stellata for the Reasons that Cardinal Capponi most ingeniously enumerates in a short but well-grounded Tract of his not because that indeed it would not both by Purlings and by Breaches occasion some inconvenience especially in the beginning but because I hold this for the incomodities of it to be a far less evil than any of the rest and because that by this means there is no occasion given to them of Ferrara to explain that they are deprived of the hope of ever seeing the Po again under the Walls of their City To whom where it may be done it is but reason that satisfaction should be given It is certain that Po was placed by Nature in the midst of this great Valley made by the Appennine Hills and by the Alps to carry as the Master-Drain to the Sea that is the grand receptacle of all Waters those particular streams which descend from them That the Reno by all Geographers Strabo Pliny Solimas Mella and others is enumerated among the Rivers that fall into the said Po. That although Po should of it self change its course yet would Reno go to look it out if the works erected by humane industry did not obstruct its passage so that it neither is nor ought to seem strange if one for the greater common good should turn it into the same Now at Stellata it may go several waies into Po as appeareth by the levels that were taken by my Order of all which I should best like the turning of it to la Botta de' Ghislieri carrying it above Bondeno to the Church of Gambarone or a little higher or lower as shall be judged least prejudicial when it cometh to the execution and this for two principal reasons The one because that then it will run along by the confines of the Church Pâ—trimony without separating Ferrara from the rest of it The other is Because the Line is shorter and consequently the fall greater for that in a space of ten miles and one third it falleth twenty six feet more by much than is required by Artists and would go by places where it could do but little hurt notwithstanding that the persons interressed study to amplifie it incredibly On the contrary there are but onely two objections that are worthy to be examined One That the Drains and Ditches of S. Bianca of the Chanel of Cento and of Burana and all those others that enter into Po do hinder this diversion of Reno by the encreasing of the waters in the Po. The other is that Po rising about the Transom of the Pilaster-Sluice very near 20 feet the Reno would have no fall into the same whereupon it would rise to a terrible height at which it would not be possible to make or keep the Banks made so that it would break out and drown the Meadowes and cause mischiefs and damages unspeakable and irreparable as is evident by the experiment made upon Panaro which being confined between Banks that it might go into Po this not being neither in its greatest excrescense it broke out into the territories of Final and of Ferrara And though that might be done it would thereupon ensue that there being let into the Chanel of Po 2800. square feet of water for so much we account those of Reno and Panaro taken together in their greatest heights the superficies of it would rise at least four feet insomuch that either it would be requisite to raise its Banks all the way unto the Sea to the same height which the treasures of the Indies would not suffice to effect or else there would be a necessity of enduring excessive Breaches To these two Heads are the Arguments reduced which are largely amplified against our opinion and I shall answer first to the last as most material I say therefore that there are three cases to be considered First Po high and Reno low Secondly Reno high and Po low Thirdly Reno and Po both high together As to the first and second there is no difficulty in them for if Po shall not be at its greatest height Reno shall ever have a fall into it and there shall need no humane Artifice about the Banks And if Reno shall be low Po shall regurgitate and flow up into the Chanel of it and also from thence no inconvenience shall follow The third remains from which there are expected many mischiefs but it is a most undoubted truth that the excrescencies of Reno as coming from the adjacent Appennines and Rains are to continue but seven or eight hours at most and so would never or very rarely happen to be at the same time with those of Po caused by the melting of the snowes of the Alps at least 400. miles distance from thence But because it sometimes may happen I reply that when it cometh to pass Reno shall not go into Po but it shall have allowed it one or two Vents namely into the Chanel of Ferrara as it hath ever had and into Sanmartina where it runneth at present and wherewith there is no doubt but that the persons concerned will be well pleased it being a great benefit to them to have the water over-flow their grounds once every four or five years instead of seeing it anoy them continually Yea the Vent may be regulated reserving for it the Chanel in which Reno at present runneth and instead of turning it by a Dam at la Betta de Ghislieri perhaps to turn it by help of strong Sluices that may upon all occasions be opened and shut And for my part I do not question but that the Proprietors themselves in Sanmartina would make a Chanel for it which receiving and confining it in the time of the Vents might carry the Sand into the Po of Primaro Nor need there thence be feared any stoppage by Mud and Sand since that it is supposed that there will but very seldom be any necessity of using it so that time would be allowed upon occasion to scowr and cleanse it And in this manner all those Prodigies vanish that are raised with so much fear from the enterance of the Water of Reno swelled into Po when it is high to which there needeth no other answer yet neverthelesse we do not take that quantity of Water that is carried by Reno and by Panaro to be so great as is affirmed For that P. D. Benedetto Castelli hath no lesse accutely than accurately observed the measures of this kind noting that the breadth and depth of a River is not enough to resolve the question truly but that there is respect to be had to the velocity of the Waters and the term of time things hitherto not considered by the Skilful in these affairs and therefore they are not able to say what quantity of Waters the said Rivers carry nor to conclude of the risings that will follow thereupon Nay it is most certain that if all the Rivers that fall into Po which are above thirty should rise at the
rate that these compute Reno to do and hundred feet of Banks would not suffice and yet they have far fewer So that this confirmes the Rule of R. P. D. Benedetto namely that the proportion of the height of the Water of Reno in Reno to the height of the Water of Reno in Po is compounded of the proportion of the breadth of the Chanel of Po to that of Reno and of the velocity of the Water of Reno in Po to the velâ—city of the Water of Reno in Reno a manifest argument that there cannot in it by this new augmentation of Waters follow any alteration that necessitates the raising of its Banks as appeareth by the example of Pavaro which hath been so far from swelling Po that it hath rather asswaged it for it hath carried away many Shelfs and many Islets that had grown in its Bed for want of Waters sufficient to bear away the matter of Land-floods in so broad a Chanel and as is learnt by the trial made by us in Panaro with the Water of Burana for erecting in the River standing marks and shutting the said Sluice we could see no sensible abatement nor much less after we had opened it sensible increasment by which we judge that the same is to succeed to Po by letting in of Reno Burana having greater proportion to Panaro than Reno to Po considering the state of those Rivers in which the Observation was made So that there is no longer any occasion for those great raisings of Banks and the danger of the ruptures as well of Reno as of Po do vanish as also the fear lest that the Sluices which empty into Po should receive obstruction which if they should yet it would be over in a few hours And as to the Breaches of Panaro which happened in 1623. I know not why seeing that it is confessed that the Po was not at that time at its height one should rather charge it with the crime than quit it thereof The truth is that the Bank was not made of proof since that the same now continueth whole and good and Panaro doth not break out nay there was when it brake more than a foot and half of its Banks above the Water and to spare but it broke thorow by a Moles working or by the hole of a Water-Rat or some such vermine and by occasion of the badness of the said Banks as I finde by the testimony of some witnesses examined by my command that I might know the truth thereof Nor can I here forbear to say that it would be better if in such matters men were more candid and sincere But to secure our selves neverthelesse to the utmost of our power from such like Breaches which may happen at the first by reason of the newnesse of the Banks I presuppose that from Po unto the place whence Reno is cut there ought to be a high and thick Fence made with its Banks so that there would be no cause to fear any whatsoever accessions of Water although that concurrence of three Rivers which was by some more ingeniously aggravated than faithfully stated by that which was said above were true to whom I think not my self bound to make any farther reply neither to those who say that Po will ascend upwards into Reno since that these are the same persons who would introduce a small branch of the said Po into the Chanel of Ferrara that so it may conveigh to the Sea not Reno onely but also all the other Brooks of which we complained and because that withal it is impossible that a River so capacious as Po should be incommoded by a Torrent that as I may say hath no proportion to it I come now to the businesse of the Ditches and Draines and as to the Conveyance of Burana it hath heretofore been debated to turn it into Main-Po so that in this case it will receive no harm and though it were not removed yet would it by a Trench under ground pursue the course that it now holdeth and also would be able to dis-imbogue again into the said new Chanel of Reno which conforming to the superficies of the Water of Po would continue at a lower level than that which Panara had when it came to Ferrara into which Burana did neverthelesse empty it self for some time The Conveyance or Drain of Santa Bianca and the little Chanel of Cento may also empty themselves by two subterranean Trenches without any prejudice where they run at present or without any more works of that nature they may be turned into the said new Chanel although with somewhat more of inconvenience and withall the Chanel of Ferrara left dry would be a sufficient receptacle for any other Sewer or Drain whatsoever that should remain there All which Operations might be brought to perfection with 150. thousand Crowns well and faithfully laid out which summ the Bolognesi will not be unwilling to provide besides that those Ferraresi ought to contribute to it who shall partake of the benefit Let me be permitted in this place to propose a thing which I have thought of and which peradventure might occasion two benefits at once although it be not wholly new It was in the time of Pope Paul V. propounded by one Crescenzio an Ingineer to cut the Main-Po above le Papozze and having made a sufficient evacuation to derive the water thereof into the Po of Adriano and so to procure it to be Navigable which was not at that time effected either by reason of the oppositions of those whose possessions were to be cut thorow or by reason of the great sum of money that was necessary for the effecting of it But in viewing those Rivers we have observed that the sedge cutting might easily be made below le Papozze in digging thorow the Bank called Santa Maria drawing a Trench of the bigness that skilful Artists shall judge meet unto the Po of Ariano below the Secche of the said S. Maria which as being a work of not above 160. Perches in length would be finished with onely 12000. Crowns First it is to be believed that the waters running that way would nor fail to open that Mouth into the Sea which at present is almost choakt up by the Shelf of Sand which the new Mouth of Ponto Virro hath brought thither and that it would again bring into use the Port Gero and its Navigation And haply experience might teach us that the superficies of Po might come to fall by this asswagement of Water so that the accession of Reno would questionless make no rising in it Whereupon if it should so fall out those Princes would have no reason to complain who seem to question lest by this new accession of water into Po the Sluices might be endangered Which I thought not fit to omit to represent to your Lordship not that I propose it to you as a thing absolutely certain but that you might if you so pleased lay it before persons whose
against the Law of God Since that thereby the same measure is made sometimes greater and sometimes lesser A disorder so enormous and execrable that I shall take the boldness to say that for this sole respect it ought to be condemned and prohibited likewise by human Law which should Enact that in this business there should be imployed either this our Rule or some other that is more exquisite and practicable whereby the measure might keep one constant and determinate tenor as we make it and not as it is now to make Pondus Pondus Mensura Mensura And this is all that I had to offer to your most Illustrious Lordship in obedience to your commands reserving to my self the giving of a more exact account of this my invention when the occasion shall offer of reducing to practice so holy just and necessary a reformation of the Measure of Running Waters and of Aqueducts in particular which Rule may also be of great benefit in the division of the greater Waters to over-flow Grounds and for other uses I humbly bow Your Most Devoted and Most Obliged Servant D. Benedetto Castelli Abb. Casin FINIS A TABLE Of the most observable matters in this Treatise of the MENSURATION of RUNNING WATERS A ABatements of a River in different and unequal Diversions is alwaies equal which is proved with 100. Syphons Page 75 Arno River when it riseth upon a Land-Flood near the Sea one third of a Brace it riseth about Pisa 6. or 7. Braces 82 B Banks near to the Sea lower than far from thence Corollary XIV 16 Brent River diverted from the Lake of Venice and its effects 64 Brent supposed insufficient to remedy the inconveniences of the Lake and the falsity of that supposition 67 Brent and its benefits in the Lake 70 Its Deposition of Sand in the Lake how great it is 78 79 Bridges over Rivers and how they are to be made Appendix VIII 20 Burana River its rising and falling in Panaro 110 C Castelli applyed himself to this Study by Order of Urban VIII 2 Chanel of Navigation in the Valleys of Bologna and its inconveniences 99 Carried into the Po of Ferrara and its benefits ibid. Ciampoli a lover of these Observations of Waters 3 D Difficulty of this business of Measuring Waters 2 Disorders that happen in the distribution of the Waters of Aqueducts and their remedies 113 Distribution of the Waters of Fountains and Aqueducts Appendix X. 22 Distribution of Water to over-flow Grounds Appendix XI 23 69 70 Diversion of Reno and other Brooks of Romagna advised by P. Spernazzati to what end it was 100 Drains and Ditches the benefit they receive by cutting away the Weeds and Reeds Appendix IX 21 Drains and Sewers obstructed in the Diversion of Reno into Main Po and a remedy for the same 110 E Engineers unvers'd in the matter of Waters 2 Erour found in the common way of Measuring Running Waters 68 69 Errour inderiving the Water of Acqua Paola Appendix II. 17 18 Errour of Bartolotti 86 87 Errours of Engineers in the Derivation of Chenels Corollary XII 12 Errour of Engineers in Measuring of Reno in Po. Appendix III. ibid. Errour of other Engineers contrary to the precedent Appendix IV. ibid. Errour of Giovanni Fontana in Measuring Waters Corollary XI 9 Errour of Giulio Frontino in Measuring the Waters of Aqueducts Appendix I. 17 Errours committed in cutting the Bank at Bondeno in the swellings of Po Corollary XIII 81 F Fenns Pontine Drained by Pope Sixtus Quintus with vast expence 92 The ruine and miscarriage thereof 93 Tardity of the principal Chanel that Drains them cause of the Drowning ibid. They are obstructed by the Fishing-Wears which swell the River 94 Waters of Fiume Sisto which flow in great abundance into the Evacuator of the said Fenns 94 95 Remedies to the disorders of those Fenns 95 96 Fontana Giovanni his errours in Measuring Waters Corollary XI 9 Fiume Morto whether it ought to fall into the Sea or into Serchio 79 Let into Serchio and its inconveniences 79 80 The dangerous rising of its Waters when to be expected 81 Its inconveniences when it is higher in level than Serchio and why it riseth most On the Sea-coasts at such time at the Winds make the Sea to swell 83 G Galilaeo Galilaei honourably mentioned Page 2 28 His Rules for measuring the time 49 H Height vide Quick Heights different made by the same stream of a Brook or Torrent according to the divers Velocities in the entrance of the River Corollary I. 6 Heights different made by the Torrent in the River according to the different heights of the River Corollary II. ibid. K Knowledge of Motion how much it importeth 1 L Lake of Perugia and he Observation made on it Appendix XII 42 Lake of Thrasimenus and Considerations upon it a Letter written to Sig. Galilaeo Galilaei 28 Lake of Venice and Considerations upon it 63 73 Low Waters which let the bottom of it be discovered 64 The stoppage and choaking of the Ports a main cause of the disorders of the Lake and the grand remedy to those disorders what it is 66 Lakes and Meers along the Sea-ccosts and the causes thereof 65 Length of Waters how it is to be Measured 70 M Measure and Distributions of Waters Appendix V. 18 Measure of Rivers that fall into others difficult Coroll X. 9 Measure of the Running Water of a Chanel of an height known by a Regulator of a Measure given in a time assigned Proposition I. Problem I. 50 Measure of the Water of any River of any greatness in a time given Proposition V. Problem III. 60 Measure that shewes how much Water a River dischargeth in a time given 48 Mole-holes Motion the principal subject of Philosophy 1 Mud. Vide Sand. N Navigation from Bologna to Ferrara is become impossible till such time as Reno be diverted 101 Navigation in the Lake of Venice endangered and how restored 65 70 P Perpendicularity of the Banks of the River to the upper superficies of it 37 Perpendicularity of the Banks to the bottom 37 Perugia Vide Lake Pontine Vide Fenns Ports of Venice Malamocco Bondolo and Chiozza choaked up for wâ—nt of Water in the Lake 65 Proportions of unequal Sections of equal Velocity and of equal Sections of unequal Velocity Axiome IV. and V. 38 Proportions of equal and unequal quantities of Water which pass by the Sections of different Rivers Proposition II. 39 Proportions of unequal Sections that in equal times discharge equal quantities of Water Proposition III. 41 Proportion wherewith one River falling into another varieth in height Proposition IV. 44 Proportion of the Water discharged by a River in the time of Flood to the Water discharged in an equal time by the said River before or after the Flood Proposition V. 44 Proportion of the Heights made by two equal Brooks or Streams falling into the same River Proposition VI. 45 Proportion of the Water which a River dischargeth encreasing in Quick-height
Christianus ita noverit ut cirtissima ratione vel experientiâ teneat Turpe autem est nimis perniciosum ac maxime cavendum ut Christianum de his rebus quasi secundum Christianas litteras loquentem ita delirare quilibet infidelis audiat ut quem admodum dicitur toto Caelo errare conspiciens risuÌ„tenere vix possit non tam molestum est quod errans homo derideretur sed quod auctores nostri ab tis qui foris sunt talia sensisse creduntur cum magno exitio corim de quorum salute satagimus tanquam indocti reprehenduntur atque respuuntur Cum enim quemquam de numero Christianorum eaiâ—re quam ipsi optime norunt deprehenderint vanam sententiam suam de nostris libris asserent quo pacto illis Libris credituri sunt de Resurrectione Mortuorum de spe vitae eternae Regnoque Celorum quando de his rebus quas jam experiri vel indubitatis rationibus percipere potuerunt fallaciter putaverint esse conscriptos y Quid enim molestiae tristiaeque ingerant prudentibus fratribus tenerarâ—j praesumpiores satis dici non potest cum si quando de falsa prava opinione sua reprehendi convinci caeperint ab iis qui nostrorum librorum auctoritate apertissima falsitate dixerunt eosdnm libros Sanctos unde id probent proferre conantur vel etiam memoriter quae ad testimonium vâ—lere arbitrantur multa inde verba pronunciant non intelligentes neque quae loquuntur neque de quibus affirmant If this passage seem harsh the Reader must remember that I do but Translate * 〈…〉 On it s own Axis * Lux ejus colligit convertitque ad se omnia quae videntur quae moventur quae illustrantur quae calescunt uno nomine ea quae ab ejus splendore continentur Itaque Sol 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 dicitur quod omnia congreget colligatque dispersa * Si enim Sol hic quem videmus eorum quae sub sensum cadunt essentias qualitates quaeque multa sint ac dissimiles tamen ipse qui unus est aequaliterque lumen fundit renovat alit tuetur perficit dividit conjungit fovet faecunda reddit auget mutat firmat edit movet vitaliaque facit omnia unaquaque res hujus universitatis pro captu suo unius atque ejusdem Solis est particeps causasque multorum quae participent in se aequabiliter anticipatas habet certe majori raticne c. Solem stetisse dum adhuc in Hemisphaerio nostro supra scilicet Horizontem existeret Cajetan in loco * Or Poles * Gen. Chp. 〈◊〉 v. 1. * Psal. 24. 2. * Psal. 137. 1. * Chap. 1. v. 4 to 9. Psal. 104. v. 5. * Shelter * Officium * In vita ejus * Followers of that Learned Kings Hypothesis * That is 5000 miles eight of these making an Italian or English mile of a 1000. paces every pacâ— containing 5. Feet * Chap. 1. v. 4. The Motion of the Earth not against Scripture Faith is more certain than either Sense or Reason * 2 Pet. 1. 19. * Or Primum Mobile * Cardan de rerum vaâ—iet Lib. 1. Cap. 1. * P. Clavius in ultima suor Operum editione The Author first Theologically dâ—fendeâ—h the â—arths Mâ—bility approved by â—ary of the Moderns b Or In Sole posuit tabernaculum suum according to the Translation our Author followeth In Sphericall Bodies Deorsum is the Centre and Sursum the Circumference Hell is in the centre of the Earth not of the World Heaven and Eartâ— are always 〈◊〉 opposed to each other After the day of Judgment the Earth shall stand immoveable * Circa Cardines Coeli Luke 16. Alia sunt notiora nobis alia notiora natura vel secundum se Arist lib. 1. Phys. * Aut ad Umbram Which are really the great Lights in Heaven The Sun Moon and Stars are one the same thing The Earth is another Moon or Star Why the Sunne seemeth to us to move not the Earth Aeneid 3. a Eccles. c. 1. v. ult b Chap. 3. v. 11. c 1 Cor. c. 4. v. 5. d 1 Cor. c. 13. v. 12. e 1 John c. 3. v. 2. f 1 Cor. c. 13. v. 12. g Ecclesiast 15. 3. h 1 Cor. c. 2. v. 2. i Isa. c. 48. v. 17. 1 Thess. 4. Joshua c. 10. ver 12. * expected Isa. c. 38. v. 8. â— Several Motions of the Earth according to Copernicus The Earth Secundum Totum is Immutable though not Immovable The Earth cannot Secundum Totum remove out of its Natural Place The Natural Place of the Earth The Moon is an Aetherial Body The Earths Centre keepeth it in its Natural Place Gravity and Levity of Bodies what it is All Coelestial Bodies have Gravity and Levity Compressive Motion proper to Gravity the Extensive to Levity Heaven is not composed of a fift Essence differing from the matter of inferior Bodies Nor yet a Solid or dense Body but Rare * Delle Macchie solarj * Vnius Corporis simplicis unus est motus simplex et huic dua species Rectus Circularis Rectus duplex à medio ad medium primus levium ut Aeris Ignis secundus gravium ut Aquae Terra Circularis quiest circa medium competit Coelo quod neque est grave neque leve Arist. de Coelo Lib. 1. * Vide Copernicum de Revolutionibus Coelest Simple Motion peculiar to only Simple Bodies Right Motion belongeth to Imperfect Bodies and that are out of their natural Places Right Motion cannot be Simple Right Motion is ever mixt with the Circular * aequabilis * Even Circular Motion is truly Simple and Perpetual Circular Motion belongeth to the Whole Body and the Right to its parts Circular and Right Motion coincedent and may consist together in the same Body The Earth in 〈◊〉 sense it may 〈…〉 be said 〈…〉 the lowest 〈◊〉 of the World Christ in his Incarnation truly descended from Heaven and in his Asceâ—sion truly ascended into Heaven 2 Cor. c. 12. v. 3. Whether in the body or out of the body I cannot tell The Sun is King Heart and Lamp of the World himself being 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 absolutely independent The Aenigma of Plato a Circa omniâ—m Regem sunt omnia Secunda circa Secundum et Tertia circa Tertium Vide Theodo de Graec. affect curat lib. 2. Sâ—euch lib. de Parennj Philoso Eccles. c. 1. 2. 3. and almost thoout * Quod fiunt vel sunt sub sole Heaven according to Copernicus is the same with the most tenuous Aether but different from Paradice which surpasseth all the Heavens a Exod. 25. 31. b My Authour following the vulgar Translation which hath an Eligance in some things beyond ours cites the words thus Facies Candelabrum ductile de auro mundissimo Hastile ejus Calamos Sphaerulas ac Lilia ex ipso procedentia c verse 12. d or Spheres e Though our Authour speaketh here positively of nine Months c. Fathers are not agreed about the period of this planet nor that of Mercury as you may see at large in Ricciolus Almagest nov Tom. 1. part 1. l. 7. sect 3. cha 11. num 11. page 627. where he maketh Venus to consummate her Revolution in neer 225 dayes or 7 12 Mon. and Mercury in about 88 dayes or 3 Months in which he followeth Kepl. in Epitome Astronom p. 760. f vers 33 34. g 1 Kings c. 7. v. 49. 2 Chron. c. 4. vers 7. h Exod. 28. 33 34 39. v. 24 25 26. i Sap. c. 18. v. 24. k Exod. c. 28. v. 6 9 17 36. l Or totus Orbis Terrarum as the vulgar Translation hath it m Numb c. 20. v. 5. n Joel c. 1. v. 12. o Hagg. c. 2. v. 19. p Deut. c. 8. v. 8. q 1 Kings c 7. v. 20. 2 Kings c. 25. v. 17. 2 Chro. c. 3. v. 15 16. c. 4. v. 12. 13. Jerem. c. 52. v. 21 22. r Gen. c. 1. v. 1. s Psal. 67. v. 6 7. * Psal. 9 v. 5 6. * Institutionum omnium Doctrâ—narum * De Oraculis * De Divinatiâ—-ne artificiosa * De Divinatiâ—-ne Naturali Cosmologica a Nella continuatione dell Nuntio siderio b Lâ—ttera al P. Abbaâ—â— D. B. Castelli D'Aâ—cetro li. 3. Decemb. 16 9. c De Motu Aquanâ— â—ib 2. Prop. 37. p. 191. * And as is at large demonstrated by that most excellent and Honourable personage Mr. Boile in the industrious experiment of his Pneumatical Engine * Artesia * Commentarius beareth many senses but in this place signifieth a certain Register of the quantities of the Waters in the several publique Aquiducts of Rome which word I find frequently used in the Law-books of antient Civilians And by errogation we are to understand the distribution or delivering out of those stores of Water * A Coyn of Pope Julius worth six pence * Or Sluice * In Pregadi a particular Council the Senators of which have great Authority * A Venice Brace is 11 16 of our yard * A River of that name * I. Savii dell ' Acque a particular Council that take care of the Lakes and other Aquatick affairs * He here intends the Demonstrations following at the end of the first Book * Deeper * Lib. 1. * The Countrey or Province lying round the City heretofore called Latium * Or Lordship * The Popes Exchequer * Polesine is a plat of Ground almost surrounded with Bogs or waters like an Island * People of Ferrara * In Chanels made by hand * The inch of these places is somewhat bigger than ours * Of Adriano * Larghezza but misprinted
obscurity that you see SAGR. Rather in that which I do no not see for hitherto I comprehend nothing at all SALV I have already foretold it Neverthelesse we will try whether by drawing a Diagram thereof we can give some small light to the same though indeed it might better be set forth by solid bodies than by bare Schemes yet we will help our selves with Perspective and fore-shortning Let us draw therefore as before the circumference of the Grand Orb as in Fig. 4. in which the point A is understood to be one of the Solstitials and the diameter AP the common Section of the Solstitial Colure and of the plane of the Grand Orb or Ecliptick and in that same point A let us suppose the centre of the Terrestrial Globe to be placed the Axis of which CAB inclined upon the Plane of the Grand Orb falleth on the plane of the said Colure that passeth thorow both the Axis of the Equinoctial and of the Ecliptick And for to prevent confusion let us only draw the Equinoctial circle marking it with these characters DGEF the common section of which with the plane of the grand Orb let be the line DE so that half of the said Equinoctial DFE will remain inclined below the plane of the Grand Orb and the other half DGE elevated above Let now the Revolution of the said Equinoctial be made according to the order of the points DGEF and the motion of the centre from A towards E. And because the centre of the Earth being in A the Axis CB which is erect upon the diameter of the Equinoctial DE falleth as hath been said in the Solstitial Colure the common Section of which and of the Grand Orb is the diameter PA the said line PA shall be perpendicular to the same DE by reason that the Colure is erect upon the grand Orb and therefore the said DE shall be the Tangent of the grand Orb in the point A. So that in this Position the motion of the Centre by the arch AE that is of one degree every day differeth very little yea is as if it were made by the Tangent DAE And because by means of the diurnal motion the point D carried about by G unto E encreaseth the motion of the Centre moved almost in the same line DE as much as the whole diameter DE amounts unto and on the other side diminisheth as much moving about the other semicircle EFD The additions and subductions in this place therefore that is in the time of the solstice shall be measured by the whole diameter DE. Let us in the next place enquire Whether they be of the same bigness in the times of the Equinoxes and transporting the Centre of the Earth to the point I distant a Quadrant of a Circle from the point A. Let us suppose the said Equinoctial to be GEFD its common section with the grand Orb DE the Axis with the same inclination CB but the Tangent of the grand Orb in the point I shall be no longer DE but another which shall cut that at right Angles and let it be this marked HIL according to which the motion of the Centre I shall make its progress proceeding along the circumference of this grand Orb. Now in this state the Additions and Substractions are no longer measured by the diameter DE as before was done because that diameter not distending it self according to the line of the annual motion HL rather cutting it at right angles those terms DE do neither add nor substract any thing but the Additions and Substractons are to be taken from that diameter that falleth in the plane that is errect upon the plane of the grand Orb and that intersects it according to the line HL which diameter in this case shall be this GF and the Adjective if I may so say shall be that made by the point G about the semicircle GEF and the Ablative shall be the rest made by the other semicircle FDG Now this diameter as not being in the same line HL of the annual motion but rather cutting it as we see in the point I the term G being elevated above and E depressed below the plane of the grand Orb doth not determine the Additions and Substractions according to its whole length but the quantity of those first ought to be taken from the part of the line HL that is intercepted between the perpendiculars drawn upon it from the terms GF namely these two GS and FV So that the measure of the additions is the line SV lesser then GF or then DE which was the measure of the additions in the Solstice A. And so successively according as the centre of the Earth shall be constituted in other points of the Quadrant AI drawing the Tangents in the said points and the perpendiculars upon the same falling from the terms of the diameters of the Equinoctial drawn from the errect planes by the said Tangents to the plane of the grand Orb the parts of the said Tangents which shall continually be lesser towards the Equinoctials and greater towards the Solstices shall give us the quantities of the additions and substractions How much in the next place the least additions differ from the greatest is easie to be known because there is the same difference betwixt them as between the whole Axis or Diameter of the Sphere and the part thereof that lyeth between the Polar-Circles the which is less than the whole diameter by very near a twelfth part supposing yet that we speak of the additions and substractions made in the Equinoctial but in the other Parallels they are lesser according as their diameters do diminish This is all that I have to say upon this Argument and all perhaps that can fall under the comprehension of our knowledge which as you well know may not entertain any conclusions save onely those that are firm and constant such as are the three kinds of Periods of the ebbings and flowings for that they depend on causes that are invariablâ— simple and eternal But because that secondary and particular causes able to make many alterations intermix with these that are the primary and universal and these secondary causes being part of them inconstant and not to be observed as for example The alteration of Winds and part though terminate and fixed unobserved for their multiplicity as are the lengths of the Straights their various inclinations towards this or that part the so many and so different depths of the Waters who shall be able unless after very long observations and very certain relations to frame so expeditious Histories thereof as that they may serve for Hypotheses and certain suppositions to such as will by their combinations give adequate reasons of all the appearances and as I may say Anomalie and particular irregularities that may be discovered in the motions of the Waters I will content my self with advertising you that the accidental causes are in nature and are able to produce