the root some quantity of water which is always soaking and gliding down from the Branches and body of the Tree the leaves sprigs and branches of the said trees collecting and condensing continually the moyst part of the Air the same being indeed a true and lively representation of a River Nor has it been my observation alone but the same is mentioned by divers Authors And it is affirmed by some Authors that there are some Islands in the Torrid Zone which have no other water in them than what is condensed out of the Air by the Trees at the tops of the Hills and converted into drops of Rain Sixthly That it is generally observed whereever there are high Hills there are generally many Springs round about the bottoms of them of very fresh and clear water and often times some which rise very near the tops of them which seems to proceed from their great elevation above the other plain superficial parts of the earth whereby the Air being dashed and broken against them they help to condense the vapours that are elevated into the higher and cooler Regions of the Air and so serve like Filtres to draw down those vapours so condensed and convey them into the Valleys beneath And hence it is very usual in Countries where there are high Hills to see the tops of them often covered with clouds and mists when it is clear and dry weather beneath in the Valleys And in the passing through those clouds on the top I have very often found in them very thick mists and small rain whereas as soon as I have descended from the higher into the lower parts of the Hills none of that mist or rain hath fallen there though I could still perceive the same mists to remain about the top Consonant to this Observation was one related to me by an ingenious Gentleman Mr. G.T. who out of curiosity with other Gentlemen whilst he lived in the Island of Teneriff one of the Canaries made a journey to the top of that prodigious high Mountain called the Pikc. The substance of which to this purpose was that the Caldera or hollow Cavity at the very top thereof he observed to be very slabby and moyst and the earth to slip underneath his feet being a very moyst soft Clay or Lome like mortar And farther that at a Cave not far from the top there was a great quantity of very fresh water which was continually supplied though great quantities of Ice were continually fetch'd from thence and carried down into the Island for cooling their Wines Consonant to which Observation was that which was related to me by the Inquisitive Mr. Edmund Hally made in St. Helena whilst he stayed there to observe the places of the Stars of the Southern Hemisphere in order to perfect the Coelestial Globe Having then placed himself upon one of the highest Prominences of that small Island which he found to be no less than 3000 foot Perpendicularly above the Surface of the Sea next adjoyning supposing that might be the most convenient place for his designed observation He quickly found his expectation much deceived as to that purpose for which he chose it for being gotten so high into the Air the motion of it was so violent as much to disturb his Instruments but which was more he found such abundance of mists and moysture that it unglued the Tubes and covered his Glasses presently with a Dew and which was yet more the foggs and mists almost continually hindred the sight of the Stars But upon removing to a lower station in the Island he was freed from the former Inconveniences I could relate many Histories of this nature whereby it seems very probable that not only Hills but Woods also do very much contribute to the condensing of the moysture of the Air and converting it into water and thereby to supply the Springs and Rivulets with fresh water And I am confident whosoever shall consider his own observation of this nature and compare them with this Theory will find many arguments to confirm it However Nullius in verba Let Truth only prevail and Theories signifie no further than right reasoning from accurate Observations and Experiments doth confirm and agree with them Having thus delivered here somewhat of my own thoughts concerning Springs and Rivers finding among some of my Papers a Relation wherein a very strange subterraneous Cistern is mentioned I have here subjoyned it as I received it from Mr. Thomas Alcock from Bristol who together with Sir Humphry Hooke was by whilst Captain Samuel Sturmy made this inquiry and who by interrogatories made to him penn'd this Relation for him as it follows verbatim IN pursuance of His Majesties Commands to me at the presenting of my Mariners Magazine I have with much diligence some charge and peril endeavoured to discover that great Concavity in the earth in Glocester shire four miles from Kingrode where His Majesties great Ships ride in the Severn And I find by experience that what has been reported of that place is fabulous whilst I thus describe it Upon the second of July 1669. I descended by Ropes affixt at the top of an old Lead Oare Pit four Fathoms almost perpendicular and from thence three Fathoms more obliquely between two great Rocks where I found the mouth of this spacious place from which a Mine-man and my self lower ourselves by Ropes twenty five Fathoms perpendicular into a very large place indeed resembling to us the form of a Horse-shoo for we stuck lighted Candles all the way we went to discover what we could find remarkable at length we came to a River or great Water which I found to be twenty fathoms broad and eight fathoms deep The Mine-man would have perswaded me that this River Ebbed and Flowed for that some ten fathoms above the place we now were in we found the water had sometime been but I proved the contrary by staying there from three hours Floud to two hours Ebb in which time we found no alteration of this River besides it's waters were fresh sweet and cool and the Surface of this water as it is now at eight fathom deep lies lower than the bottom of any part of the Severn Sea near us so that it can have no community with it and consequently neither flux nor reflux but in Winter and Summer as all Stagna's Lakes and Loughs which I take this to be has As we were walking by this River thirty two fathoms under ground we discovered a great hollowness in a Rock some thirty foot above us so that I got a Ladder down to us and the Mine-man went up the Ladder to that place and walk'd into it about threescore and ten paces till he just lost sight of me and from thence chearfully call'd to me and told me he had found what he look'd for a rich Mine but his joy was presently changed into amazement and he returned affrighted by the sight of an evil Spirit which we cannot perswade him but he saw and
the face of the waters And for this I could produce very many Histories and Arguments that would make it seem very probable but that I reserve them in the Lectures which I read of this subject in Gresham Colledge in the years 1664 and 1665 which when I can have time to peruse I may publish Therein I made it probable that most Islands have been thrown up by some subterraneous Eruptions Such is the Island of Ascension the Moluccus c. Secondly that most part of the Surface of the Earth hath been since the Creation changed in its position and height in respect of the Sea to wit many parts which are now dry Land and lie above the Sea have been in former Ages covered with it and that many parts which are now covered with the Sea were in former times dry Land Mountains have been sunk into Plains and Plains have been raised into Mountains Of these by observations I have given instances and shewed that divers parts of England have in former times been covered with the Sea there being found at this day in the most Inland parts thereof susficient evidences to prove it to wit Shells of divers sorts of Fishes many of which yet remain of the animal substance though others be found petrified and converted into stone Some of these are found raised to the tops of the highest Mountains others sunk into the bottoms of the deepest Mines and Wells nay in the very bowels of the Mountains and Quarries of Stone I have added also divers other instances to prove the same thing of other parts of Europe and have manifested not only that the lower and plainer parts thereof have been under the Sea but that even the highest Alpine and Pyrenean Mountains have run the same fate Many Instances of the like nature I have also met with in Relations and observations made in the East as well as in the West Indies Of all which strange occurrences I can conceive no cause more probable than Earthquakes and subterraneous Eruptions which Histories do sufficiently assure us have changed Sea into Land and Land into Sea Vales into Mountains sometimes into Lakes and Abysses at other times and the contrary unless we may be allowed to suppose that the water or fluid part of the earth which covered the whole at first and afterward the greatest part thereof might in many Ages and long process of time be wasted by being first raised into the Atmosphere in vapours and thence by the diurnal but principally by the annual motion thereof be lost into the ather or medium through which it passes somewhat like that wasting which I have observed to be in Comets and have noted it in my Cometa Or unless we may be allowed to suppose that this fluid part is wasted by the petrifaction and fixation of such parts of it as have fallen on the Land and Hills and never returned to fill up the measure of the Sea out of which it was exhaled for which very much may be said to make it probable that the water of the earth is this way daily diminished Or unless since we are ascertained by observations that the direction of the Axis of the earth is changed and grown nearer the Polar Star than formerly that the Magnetism or Magnetical Poles are varied and do daily move from the places where they lately were and that there are other great and noted changes effected in the earth we may be allowed to conceive that the Central point of the attractive or gravitating power of the earth hath in long process of time been changed and removed also farther from us towards our Antipodes whence would follow a recess of the waters from these parts of the world to those and an appearance of many parts above the surface of the water in the form of Islands and of other places formerly above the Sea now in the form of Mountains so to continue till by the libration or other-ways returning motion thereof it repossess its former seat and place and overwhelms again all those places which in the interim had been dry and uncovered with the return of the same water since nothing in nature is found exempt from the state of change and corruption Further it is probable that Earthquakes may have been much more frequent in former Ages than they have been in these latter the consideration of which will possibly make this Assertion not so Paradoxical as at first hearing it may seem to be though even these latter Ages have not been wholly barren of Instances of the being and effects of them to convince you of which I have hereunto subjoyned a Relation and account of one very newly which hapned in the Isle of Palma among the Canaries Next the clearness of the Air is very remarkable which made an Island which lay eight Leagues off to look as if it were close by To this purpose I have often taken notice of the great difference there is between the Air very near the lower Surface of the Earth and that which is at a good distance from it That which is very near the earth being generally so thick and opacous that bodies cannot at any considerable distance be seen distinctly through it But the farther the eye and object are elevated above this thick Air the more clear do the objects appear And I have divers times taken notice that the same object seen from the top and bottom of a high Tower hath appeared twice as far off when seen at the bottom as when seen at the top For the Eye doth very much judge of the distance of Objects according as the Density of the Air between the Eye and Object doth represent them Hence I have seen men look of Gigantick bigness in a fog caused by reason that the Fog made the Eye judge the Object much farther off than really it was when at the same time the visible Angle altered not This great thickness of the lower Air is sufficiently manifest in the Coelestial bodies few of the fixt Stars or smaller Planets being visible till they are a considerable way raised above the Horizon The third remark about the moistness of the fogs and the production of water at that height I have before insisted on Only the almost continual fogs that this Gentleman observed in the Wood they passed is very remarkable for the origine of Springs Nor shall I say any thing concerning the vast perpendicular height of the same but for a close of this present collection I shall add the short account of the Eruption which lately hapned in the Palma A true Relation of the Vulcanos which broke out in the Island of the Palma Novemb. 13. 1677. SAturday the thirteenth of November 1677. a quarter of an hour after Sun set hapned a shaking or Earthquake in the Island of St. Michael de la Palma one of the Canary Islands from the lower Pyrenna and within a League of the City unto the Port of Tassacorte which is accounted
obvious to any knowing Mechanick and that without the help of Tooth-wheels or Pinions which in works of this nature are in no wise to be made use of by reason of their shaking and uncertainty which I shall elsewhere describe There is one only difficulty in this motion and that is only in such Objects as pass over or very near the Zenith or Nadir of the place for in those cases when the Object comes very near the Zenith the obliquity of the motion of the one to the other is so very great that the first Axis doth not move the second without some difficulty But to remedy this the expedient is as easie and that is by having a little barrel about the perpendicular Arm to carry it forward as far and as fast as the first Inclined axis will permit it which weight may be removed as soon as the Object is a little way past the Zenith The next use that may be made of this is for carrying the Hand of a Clock so as alwaies to move over that point of the Ecliptick in which the Sun is in a Stereographical projection of the Sphere upon the Plain of the Equinoctial or in an Orthographical projection of the said Sphere upon the same Plain so as to express thereby not only the differing right ascensions but the anomaly also of the Suns motion in the excentrick of the Ecliptick And by this means the Face of the Clock may be made by a Planispherical projection to represent the motion of all the Stars appearing in any Horizon that is not too near the Equinoctial their Risings settings culminatings azimuths and almicauters Risings and settings of the Sun the lengths of the Days and Nights and of the Twilights and Dawnings and many other Problems of the Sphere And which is a consequent of this it may be made to shew the equation of Time which is necessary to be made use of for setting a pendulum Clock by the Sun the manner of doing which I must refer to another opportunity as I must also the use of this Joynt for drawing Ellipses drilling and boring of bending Holes for turning Elliptical and Swash-work till I publish my description of a Turning Engine capable to turn all manner of Conical Lines and Conoeidical all manner of Foliage and Flower-work all variety of Basket or Breaded-work all variety of Spiral and Helical-work serving for the imitation of the various forms and carvings of all sorts of Shells for cylindrical and conical Screws all variety of Embossments and Statues all variety of edged and Wheel-like work all variety of Regularly shaped Bodies whether the five Regular bodies of Plato or produced from those by various sections or additions of which the variety is infinite all variety of bended Cylinders or Cones and those whether round in the manner of an Oxes-horn or compressed and angular like those of a Ram or Goat for all manner of Swasht-work Comprest-work c. every of which principal parts hath a vast variety and the compound and decompound principles have a variety almost infinite Appendix Concerning the Eclipse of the Moon observed in London JAnuary the first 167 4 5 being at Sr. Jonas Mores in the Tower of London and making use of a Telescope of eight foot and my pocket-Watch whose ballance was regulated with springs I observed the Eclipse of the Moon which began at about twenty minutes after five the penumbra very much cheating the naked eye for the Penumbra had darkned that side of the Moon next the spot Grimaldi about half an hour before and grew darker and darker towards the edge where the Umbra entred so that if the light of the Moon were diminished either by reflection upon dark Glass or looking through a small hole between a quarter and a third part of the Moon seemed eclipsed before the Umbra entred but the Telescope discovered it plainly to be no true umbra but penumbra This I note because such Persons as do not make use of a Telescope but only of their naked eye are very apt to be much deceived in their estimation of the beginning and end of the Eclipse At 5.48 we judged by the Telescope that the Moon was eclipsed six digits or half at 6.19 the total Eclipse began when the Moon appeared of a very red colour especially towards that part of the Limb where the direct Raies left it which was at the Mare Crisium which is opposite to Grimaldi Now the Skie being somewhat clearer it being before hazy with the Telescope I began to discover a great number of small Stars about the Moon which appeared yet much more conspicuous after I had taken off the apperture from the Object-glass and amongst the rest one seemed very conspicuous and lay in the way of the Moon which I diligently watched and observed that it was just covered by the Moon at 6h. 47′ 30″ the Moon first covering it with that part of it which was almost perpendicularly under the centre of the Moon About three quarters of an hour after the total immersion the body of the Moon was exceeding dark and almost unperceivable being then near the centre of the Umbra and afterwards the Eastermost or foremost part of the Limb of the Moon began to be inlightned whereas before the Westermost Limb had been the brightest This was also very notable that that part of the Moon that was towards the North-Pole a pretty while before the emersion of the Moon out of the total Eclipse and even till the very emersion and somewhat after too appeared inlightned with a much brisker light than any other part of the body except that which was next the Limb where the light again entred From what cause this should happen I know not possibly it might be caused by a greater refraction of the Air near the North-Pole of the Earth and I am much troubled that I had not taken notice whether the like phenomenon had not happened to the body of the Moon before it had past the centre of the Umbra It was very manifest that there was a considerable quantity of light that kept that Limb of the Moon which was next the light conspicuous by the Telescope all the time of the total Eclipse and 't is very rational to ascribe it to the Raies of the Sun refracted by the Air or atmosphere of the Earth I was very well pleased to observe the Moon to cover several small Stars that lay in its way but I kept no account of them but only watched diligently when the Star that entred behind the Moon at 6.47.30 would come out again which I found it to do at 7 30′ seeing it at the very moment of time that it began to appear again And it was also at the same instant discovered by Sr. Jonas More who was expecting it with another Tube At 7.58 the body of the Moon first emerged out of the Umbra at the spot Grimaldi and soon after all those small Stars that were
Mathematical of the way celerity and magnitude of Comets have been prosecuted with very much care and great skill such as those of the noble Tycho and the learned and diligent Hevelius insomuch that I could not expect to have better yet as to Physical remarks I wanted much information to be able to satisfie many difficulties that occurr'd to my thoughts upon enquiry into the particular natures of them I did therefore as I designed employ all the time I could get of observing this Comet in taking notice of such circumstances as I judged would be pertinent to resolve any of those Queries I had formerly made in order to find out the nature of Comets in general And though the little opportunity I now had and the disadvantageous appearance of this last were very short of giving me that satisfaction in many particulars which I wish'd for and expected at first yet since they may possibly serve for hints to others that may hereafter have better oportunity than I and that I might understand what material objections could be made by observers from preceding Comets and that they might for the future more diligently take notice of what from these queries and hints may be judged significant to this design such as they are I have here published as I had done formerly by my Lectures in Gresham-Colledge those which I had made of those in 1664. and 1665. Now before I come to make relexions upon these remarks I thought it might not be improper to add some few of those things concerning those two former Comets observed by me in the said years I say some few because it would be needless to set down all especially such of mine as do agree with others since published I did therefore soon after I had seen the first Comet to wit December 23. 1664. propound to my self certain Queries necessary to be answered in order to find out a true theory of them and directed my Observations accordingly and they were these Of what substance its body beard and blaze is and next of what magnitude each of those parts appear and of what real magnitude they are Other Queries were concerning its density and rarity its mutability or immutability that is whether it dissolved and wasted or not whether it were fluid or solid whether it participated of gravity or levity Whence it had its light colour c. What was the sigure of the Star Radiation Blaze c. Whether the Blaze were always opposite to the Sun or deflected whether straight or bended c. What kind of motion it was carried with whether in a straight or bended line and if bended whether in a circular or other curve as elliptical or other compounded line whether the convex or concave side of that curve were turned towards the earth Whether in any of those lines it moved equal or unequal spaces in equal times Through what parts of the universe it moved and how far distant it was at several times Whether in the lower Regions near the Earth in the Atmosphere or near it or in the Heavens or fluid AEther with which the space of the Heavens is filled Whether above or below the Moon c. Whether it wasts and is dispersed and consumed or whether it lasts and endures for a longer time If it lasts Whether it ever appears again being moved in a circle or be carried clear away and never appear again being moved in a straight or paraboloeidical line Whether it be collected or generated when it first appears and dissipated or destroyed when it disappears or whether the several distances of it do not make that appearance Whether it may not have some such propriety as the Star in Cete whereby it may shine and appear for a certain period and again lose its light and disappear by several vicissitudes and whether that may not give some account of the appearance of so many Comets about Aries First As concerning the matter or substance of the Nueleus Star or body of the hazy shining part encompassing it and of the Tail or Blaze I say that by comparing all the circumstances that I was able to take notice of from the beginning to the end I found that the Star in the head was of a very compacted and dense light and almost equalled that of Saturn though it were not like that confined by an equal limb that there were some parts distinguishable in this body some having a brighter others a fainter light That these parts did not continue the same but considerably varied which might in part be caused by the differing position of those parts which were seen before from the same seen afterwards in respect of the eye situate on the surface of the Earth moved one way and the Comet moved another though I do not conceive it wholly ascribable to that but partly also to a real alteration of the parts of the Comet That I did very diligently watch to observe if it were possible when it pass'd over any fix'd Star to find whether it were transparent as I had several times observed the tail of it to be even in its brightest parts but I had not the opportunity but that I did several times observe the tail of it transparent not only with the naked eye but through a Telescope if at least the fixed Stars be above it which I think few doubt that the light diminish'd by degrees towards the extremes of the hazy part encompassing it and yet the extremes of it as to that part of it which respected the Sun seemed pretty evenly and smoothly defined especially through a Telescope From all which remarks and from the velocity of its motion I conjecture it to be made up of solid matter not fluid that the body of it especially is considerably dense but that the haziness or Coma about it is much more rarified and the tail thereof is most of all That this body is encompassed with a body most fluid and easily permeable and which doth with very little resistance give way to the motion of it or any other body through it that it doth easily admit at least if not actually take into it self the parts of this body Coma and Blaze I say admit at least though there may be many reasons alledged that it doth actually prey upon and dissolve those parts into it self as I shall shew by and by because that we find that the extreme parts do extend but to such a distance and beyond that there is no appearance of light and that the light is from it self and not produced by refraction or reflexion of the beams of the Sun I shall shew reasons by and by And consequently where there is most light appears there are the greatest number and there is the greatest density of the Cometical parts The middle of the body may be as dense as the body of the earth and I have not observed my self nor met with any body else that hath taken notice of any thing to the
Parallax of divers minutes but whereas I could not certainly distinguish any sensible at all it must be many times higher than the Moon Now that this way is abundantly to be preferred before an Observation made with a Quadrant for the taking of its altitude is pretty evident because by this means the greatest part of the irregularity caused by the refraction or inflection of the Air is removed for by this means though the Parallax be very large yet the refraction or inflection of the Air will not amount to many seconds both the objects being almost equally raised by refraction especially when 5 or 10 degrees high nearer than which the small Stars vanished out of sight by the thickness of our air It follows therefore that a Semidiameter of the Earth must be a very inconsiderable measure in its distance This part therefore of the Theory of Comets hath been much defective hitherto If we enquire the Parallax of them from the Observation of divers men made in differing places we shall find them so differing one from another that there is great reason to suspect them all Nay not only so but in this Comet of 1664. by comparing two Tables or Charts of the Stars and Constellations of that part of the Heavens through which the Comet past on which was also markt out its way and place from day to day both of them Printed from Copper Plates I find that strange errors and mistakes may be created notwithstanding all the Authors thors care and accurateness possible from the carelesness or neglect of the Graver This I noted in the two Tables of the learned and accurate Mathematician P. Aegidius Franciscus de Gotignies whose skill and care from other works of his and other Observations of this Comet I am sufficiently assured of and found that by the first table upon the ⅔½ of December 1664. it was in 4½ of II in Longitude and in 33⅔ of Southern Latitude but by the second it is placed at the same time in 4°II for its Longitude and in 34½ of South Latitude And this error is not only committed in the place of the Comet but also in the place of the fix'd Stars for Riget in the first Table is placed in 30¾ South Latitude and in 12¾II for Longitude but in the second in 31½ South Latitude and in II ½ II for Longitude both which differ considerably from the place of it assigned by Riccioli and Grimaldi according to whose Observations it should be in 31. II′ South Latitude and 12° II′ 40″ II in Longitude Now if there be these differences to be remarked in the Observations of one we cannot but expect that much more disagreement should be found between those which have been made by differing persons in differing places and with differing ways and differing Instruments And upon examination I have found it no better for from comparing such Observations as I have received from several parts of the world even of those which have seemed more than ordinarily exact I find them for the most part so unaccurate that though they sufficiently manifest that the Comet of 1664. which lasted above four months was visible in most parts of the world and seen to pass in all those places pretty near in the same way amongst the fixed Stars Yet they are so far from manifesting the Parallax that some of them make the place of the Comet to be quite contrary to what parallax would make it some of the Southern Observators placing it much more Southwardly than those of the North. Others indeed of them make the Parallax so great that one might ghess it to be not so far removed from the Earth Something indeed in the general might be ghest of the way of that Comet amongst the fix'd Stars especially when it approaches them pretty near but for exactness of Calculation for Parallax they were no way useful And evenin the former use too it seems very doubtful for comparing the Charts of the Comets way amongst the fix'd Stars published by that diligent and unwearied Observer Mr. Hevelius of Dantzick the above-mentioned P. Gottignies Professor at Rome and Monsieur Petit of Paris I find that the two former make the way of the Comet to lie below the Star in the Bill of Corvus whereas the later though in a Latitude interposed between the parallels of the former makes it to lie above or to the North of it and with him agree some Observations which I have seen of Monsieur Hugenius Other differences I found between those Tables in the way of the Comet of 64. near the middle of its arch wherein Monsieur Hevelius all the way places it more Southward than either Monsieur Petit or P. Gottignies for whereas both P. Gottignies and Mounsieur Petit make it pass above the Star of the third magnitude in the right shoulder of Lepus Monsieur Hevelius makes it move below it which seem to be ascribable to Parallax But I fear much cannot be concluded of certainty from them I shall not trouble the Reader with a multitude of other Histories which I have received concerning that Comet of 64. nor with the disagreements of them one with another and perhaps of most with the truth They have given me sufficient trouble in the examination of them having little other benefit from them save only this that I was thereby informed what a man might think of a great number of Astronomical Observations that have been made for saving the exact Observations of some few such as Mr. Hevelius Mr. Aurout P. Gottignies c. truly diligent and accurate men the greater the Collections of Observations are the more trouble and difficulty is created to the Examiner they not only confounding one another but perplexing those also which are real and perfect Now the reasons or causes of these inconveniences seem to be these First the want of accurate and knowing Observators Secondly The scarcity of convenient Instruments Thirdly The Imperfection of the Tables of the fix'd Stars For the Observators 't is not enough to know how to manage an instrument or to have a good eye or a dextrous and steady hand but with these there must be joyned a skilfulness in the theorical and speculative part and add to all a love and delight in the thing it self and even all these will signifie but little without convenient and accurate Instruments such as may be easily manageable and sufficiently exact The first of these the love of the study being in it self the most excellent or the encouragement of Princes Noblemen and other Patrons of this Learning must procure and where both of these concur thence most is to be expected and most fruit hath hitherto been proceeded though there are not wanting divers eminent instances where the first reason hath been the only inducement As to the second I have already in some of my former Lectures described several convenient ones for these purposes and therefore I shall not here add any more concerning
from several parts this Orb perpendiculars be let fall upon the Plain of the Ecliptick those perpendiculars shall fall in an Ellipsis part whereof shall fall within the Orb of the Earth in ♌ and the opposite without the Orb of ♃ ♒ That the Comet moves a Sextant of this Orb in about 130 days and consequently if its motion should continue the same in such a Circle it would appear about February March or April 1667. but being so far removed towards the South Pole will here hardly be seen but by those that live towards the South it may appear to have some such motion by the South Pole as that of 1618. had by the North. And 't is not impossible but that the Comet of 1618. might be the same with this if we suppose the Nodes of it to have a motion contrary to the order of Signs and that the same Node which in this Comet according to this supposition was in ♊ was then about ♠or ♠but these as conjectures I shall not insist on because neither in this nor in that have we Observations sufficiently accurate to build any Theory upon Now though upon these suppositions the motion and appearances of the Comet seem to be very regularly and very naturally made out yet 't is not the only Hypothesis for that design nor do I believe it so evident a demonstration for that end as some would suppose though for other reasons I am apt enough to think that opinion of the Earths motion very probable but the motion of this Comet is so well made out by the contrary supposition that I think it may be alledged for a greater argument against the motion of the Earth than for it for if we only grant one of the former postulata namely that the body of the Comet is moved equal spaces in equal times and a quite contrary postulatum to the former namely that the Earth remains fix'd as to an annual motion we may find all the observations of this Comet especially the most accurate of them to happen so that the Comet being supposed to be moved in a great Circle whose convex side is turned towards the Earth whose center is extended towards the fix'd * in ♋ and whose Semidiameter is about sixscore times the nearest distance of the Comet from the Earth and the Comet be supposed to be moved very near equal spaces in equal times we shall find I say all the appearances most exactly solved and indeed much more exactly than by the other supposition I was able to find any for by this supposition both the magnitude longitude latitude retrogradation station and direction of the Comet is most exactly made out as any one might have found that should have by this means examined with me the observations I have hitherto either made or met with and indeed all the Observations hitherto have so well answered this Hypothesis that I do almost promise my self to be able to see this Comet a month or six weeks hence after the Sun has past by it if by its exceeding elongation it be not quite grown out of sight as it is now indeed already so exceeding dim and faint that it cannot be seen without a very good glass which will endure an exceeding big aperture nor could I these two last nights perceive it though the Air were clear but the reason I attribute to its nearness to a fixed * of ♈ This Hypothesis is explained in the seventh Figure By this supposition the return of the Comet will be much longer and the time of seeing of it much more uncertain because the curvature is so little that the making the circle a twentieth or a sixteenth part bigger or less does not much alter the regularity whence 't is exceeding difficult unless we had much more accurate Observations than I have hitherto met with to determine exactly the bigness of the circle and consequently the time of the return And by this supposition the Comet may be supposed either nearer or farther from the Earth at any distance which is not contradicted by a Diurnal Parallax that is it may be supposed either above Saturn or below the Moon or in any place between by supposing only that the farther the nearest part of the Circle is distant from the Earth the greater must that Circle be and the swifter the motion of the Comet in it to prove which affirmation let in the Eighth figure A be the Earth BCD the Orb of the Comet supposed very near the Earth and E F G the Orb of it supposed at a greater distance let H be the center of B C D and I of E F G and let A C be to C H as A F to F I all the lines drawn from the point A so as to cut the Circles B C D and E F G shall divide those Circles E F G and B C D into similar segments as let A B E be a line drawn cutting those Circles in B and E I say the Arch B C shall be similar to E F. In which Hypothesis if we have together with the place of the Comet when stationary the place of it when in its greatest celerity perige or the places of it when of the same celerity on each side of its perige we have from thence the proportion of the Radius of its Orb to the perigean distance and consequently all the other distances the line in which it appears when stationary being the Tangent to the Circle in which it moves as A B E to which a Perpendicular raised at B B E and produced till it cut the line A C produced at H H I it gives the Center of its Orb H H I and the proportions of the lines A B AC B H = H C or of A E A F E I = F I the Angle B A C being given by observation So that by this Hypothesis the Phaenomena of the motion and bigness of the Comet will be solved though supposed of any distance Nor are these the only Hypotheses by which the hitherto observ'd Phaenomena may be solv'd for if we will admit an unequal motion such as is now granted to all the Planets and if further we will admit it to be moved in an Elleipsis or other such like curve there may be divers other Hypotheses that will solve the Phaenomena so that the Comet may be supposed to have no motion at all as to Longitude but only as to Latitude that is it may be supposed to be moved in an Elleipsis described in a plain which shall be at right Angles with the plain of the Ecliptick and the ways of the Earth in it it may be supposed also to have been mov'd direct according to the order of the signs that is to have been first about Gemini in respect of the Sun and to be now in some part of Leo And it is not impossible to solve the phaenomena of its periodick or proper motion though it be supposed not so high as
minute of time their motion being of such a Velocity impressed from the Ambient on the two extreme Particles 1 and 8. First if by any external power on the two extremes 1 and 8 they be removed further asunder as to CD then shall all the Vibrative Particles be proportionably extended and the number of Vibrations and consequently of occursions be reciprocally diminished and consequently their endeavour of receding from each other be reciprocally diminished also For supposing this second Dimension of Length be to the first as 3 to 2 the length of the Vibrations and consequently of occursions be reciprocally diminished For whereas I supposed 1000000 in a second of the former here can be but 666666 in this and consequently the Spring inward must be in proportion to the Extension beyond its natural length Secondly if by any external force the extreme particles be removed a third part nearer together than the external natural force being alway the same both in this and the former instance which is the ballance to it in its natural state the length of the Vibrations shall be proportionably diminished and the number of them and consequently of the occursions be reciprocally augmented and instead of 1000000 there shall be 1500000. In the next place for fluid bodies amongst which the greatest instance we have is air though the same be in some proportion in all other fluid bodies The Air then is a body consisting of particles so small as to be almost equal to the particles of the Heterogeneous fluid medium incompassing the earth It is bounded but on one side namely towards the earth and is indefinitely extended upward being only hindred from flying away that way by its own gravity the cause of which I shall some other time explain It consists of the same particles single and separated of which water and other fluids do conjoyned and compounded and being made of particles exceeding small its motion to make its ballance with the rest of the earthy bodies is exceeding swift and its Vibrative Spaces exceeding large comparative to the Vibrative Spaces of other terrestrial bodies I suppose that of the Air next the Earth in its natural state may be 8000 times greater than that of Steel and above a thousand times greater than that of common water and proportionably I suppose that its motion must be eight thousand times swifter than the former and above a thousand times swifter than the later If therefore a quantity of this body be inclosed by a solid body and that be so contrived as to compress it into less room the motion thereof supposing the heat the same will continue the same and consequently the Vibrations and Occursions will be increased in reciprocal proportion that is if it be Condensed into half the space the Vibrations and Occursions will be double in number If into a quarter the Vibrations and Occursions will be quadruple c. Again If the conteining Vessel be so contrived as to leave it more space the length of the Vibrations will be proportionably inlarged and the number of Vibrations and Occursions will be reciprocally diminished that is if it be suffered to extend to twice its former dimensions its Vibrations will be twice as long and the number of its Vibrations and Occursions will be fewer by half and consequently its indeavours outward will be also weaker by half These Explanations will serve mutatis mutandis for explaining the Spring of any other Body whatsoever It now remains that I shew how the constitutions of springy bodies being such the Vibrations of a Spring or a Body moved by a Spring equally and uniformly shall be of equal duration whether they be greater or less I have here already shewed then that the power of all Springs is proportionate to the degree of flexure viz. one degree of flexure or one space bended hath one power two hath two and three hath three and so forward And every point of the space of flexure hath a peculiar power and consequently there being infinite points of the space there must be infinite degrees of power And consequently all those powers beginning from nought and ending at the last degree of tension or bending added together into one sum or aggregate will be in duplicate proportion to the space bended or degree of flexure that is the aggregate of the powers of the Spring tended from its quiescent posture by all the intermediate points to one space be it what length you please is equal or in the same proportion to the square of one supposing the said space infinitely divisible into the fractions of one to two is equal or in the same proportion to the square of two that is four to three is equal or in the same proportion to the square of three that is nine and so forward and consequently the aggregate of the first space will be one of the second space will be three of the third space will be five of the fourth will be seven and so onwards in an Arithmetical proportion being the degrees or excesses by which these aggregates exceed one another The Spring therefore in returning from any degree of flexure to which it hath been bent by any power receiveth at every point of the space returned an impulse equal to the power of the Spring in that point of Tension and in returning the whole it receiveth the whole aggregate of all the forces belonging to the greatest degree of that Tension from which it returned so a Spring bent two spaces in its return receiveth four degrees of impulse that is three in the first space returning and one in the second so bent three spaces it receiveth in its whole return nine degrees of impulse that is five in the first space returned three in the second and one in the third So bent ten spaces it receives in its whole return one hundred degrees of impulse to wit nineteen in the first seventeen in the second fifteen in the third thirteen in the fourth eleven in the fifth nine in the sixth seven in the seventh five in the eighth three in the ninth and one in the tenth Now the comparative Velocities of any body moved are in subduplicate proportion to the aggregates or sums of the powers by which it is moved therefore the Velocities of the whole spaces returned are always in the same proportions with those spaces they being both subduplicate to the powers and consequently all the times shall be equal Next for the Velocities of the parts of the space returned they will be always proportionate to the roots of the aggregates of the powers impressed in every of these spaces for in the last instance where the Spring is supposed bent ten spaces the Velocity at the end of the first space returned shall be as the root of 19. at the end of the second as the Root of 36. that is of 19+17 at the end of the third as the Root of 51. that is of 19+17 +15. At the end of the
the Island Lipari near Sicily about sixteen Leagues from Messina it is famous for the best Raisins in the Mediterranean there is on it a large Castle a small Town many Vineyards and about one hundred Families besides some Religiose I judge it wants a fifth part of the bigness of the Isle de Mayo it is mostly very high Land especially one Mountain on which stands a Watch Tower whence a man may see a monstrous distance at Sea as is confirmed by de Ruyter In the relation he gives the States of Holland wherein he tells them that from that place they discerned the French Fleet 's approach long before they could from any other part either of their own or the other Island I am sure it is much higher than either that at the Isle de Mayo or any I have seen in England and yet on this fair fruitful Island springs not one drop of water the Inhabitants storing themselves with rain which falling very frequently they are careful to preserve in Cisterns divers essays have been made in the most promising part of it to find Springs by digging Wells one of those which I saw was without doubt the deepest in Europe I remember not the exact profundity as they related it but I have not forgot that throwing in a stone it was long ere it got to the bottom and then returned such a noise as it had been the discharge of a Musquet The cause of this driness was by the people thought to be subterranean heats absuming the water but no such thing appearing to the sense of those that digged the Wells I gave no faith to that persuasion they fancy such heats partly from the want of water but mostly because the four adjacent Islands Stromboli Vulcano Vulcanella and M. Aetna are constantly burning and very near them The obvious earth of this place is loose and in all apparent qualities very good but by the heaps that had been thrown up in digging the Wells I saw the inferiour earth was clammy or like clay that had some greasie gummous matter commixed This the Religious told me was the very kind of Sulphur which constantly boyled out of the burning Cranny on Vulcanella and where with all those Islands abounded not excepting their own though it were not yet kindled For my third observation I will go no farther than the place of my present abode Plimmouth in which on a kind of Piazza commonly called the New-key a plat of ground got in from the Sea is a Well which before the ever famous Sir Francis Drake by cutting a Rivulet of thirty miles procured us water in great plenty was of common use having as at this day a Pump in it about seven years since being before the Key was inlarged the Well was not above eigh foot from the edge thereof over which the Sea would frequently flow when a high outwind and a Spring Tide concurred I say this Well though so near the Sea yieldeth clean water and as sweet as a mixture of three parts fresh and one of salt water would be About an hundred yards from that on ground a little rising is a very large Well which supplieth three or four Brew-houses by whose drink it is evident that the water hath not wholly quitted its salt It is to be noted that Plimmouth lieth on a Peninsula three miles long and two broad the Isthmus about two thirds of a mile wide and not very high from the surface of a full Sea There are many Wells in it those near the Sea are saltish those farther from it the less so My fourth observation I take from the late famous French Traveller Monsieur Taverner who in his first Volume discoursing of the Coast of Coromandel c. he saith they there want fresh water and are constrained strained to make pits of two foot deep in the sand by the Sea to find it The fifth observation and which I would call the most significant were I assured of its truth I had from a very ingenious Chirurgeon who had used the West Indias that there is in that Sea an Island called Rotunda of a figure agreeable to its name which though very small hath on it arising in the middle a Spring of a very large stream of water at which our Ships frequently furnish themselves in their Navigation he affirmed that it raineth there but once a year as at the Isle de Mayo saying withal that the Island is so short of a proportion big enough for the stream that if it constantly rained it could not be supply enough to maintain so large an Efflux My sixth and last is the relation of Dr. Downes concerning Barbadoes viz. that all their Springs were formerly very near the Sea that up in the Country they supplied themselves from the rains by digging pits in the earth able to contain great quantities and there preserving it which they did a very long time the rains being there as unfrequent as at the Isle de Mayo and that without any sensible diminution by penetrating and descending into the earth and to prevent the loss thereof by the exhalations of the Sun they covered it with leaves c. but that now by digging deeper they find Springs so plenty that no Plantation is without one From all these observations the following consectaries do mechanically result From the first it appeareth that some Springs have manifestly their source from the Sea that sand sweetens transcolated Sea-water and that even pickle strained through it loseth much of its saltness thereby all which is evident from the Well therein mentioned whose water could not possibly be other than what soaked in from the Pond and the Ocean Hence also is manifest that constant and large Fluxes of water may be made for eleventh months without rain to refill the subterranean Cisterns supposed by you to supply them this appears from the River running through the Island by whose banks I found it being April when I was there at which time they had been ten months without rain thsh after their showers it could run but little larger that it did after so tedious a want of them I had forgot to intimate in the relation that those two Hommets A. are craggy Rocks whereon live a great number of Goats and are consequently very unfit if not incapable either to receive or contain the Magazine for the supply of the Rivulet From the second it is manifest that higher Mountains of earth and consequently more likely to receive and contain sufficient quantity of rain-rain-water to beget and supply Springs and Rivers have not always that effect although there was one great advantage more added here viz. a clammy tyte earth in the bottom to make the supposed Cistern the better able to contain the store I say that frequent rain to fill high Mountains to contain loose pervious earth to receive and a well luted bottom to support and retain being all the qualifications and circumstances supposed necessary to make and continue
therewith who have confined their imaginations fancies only within the compass and pale of their own walk and prospect who can scarce imagine that the Earth is globous but rather like some of old imagine it to be a round plain covered with the Sky as with a Hemisphere and the Sun Moon and Stars to be holes through it by which the Light of Heaven comes down that suppose themselves in the center of this plain and that the Sky doth touch that plain round the edges supported in part by the Mountains that suppose the Sun as big as a Sieve and the Moon as a Chedder Cheese and hardly a mile off That wonder why the Sun Moon and Stars do not fall down like Hail-stones and that will be martyr'd rather then grant that there may be Antipodes believing it absolutely impossible since they must necessarily fall down into the Abyss below them For how can they go with their feet towards ours and their heads downwards without making their brains addle To one I say thus prejudiced with these and a thousand other fancies and opinions more ridiculous and absurd to knowing men who can ever imagine that the uniformity and harmony of the Celestial bodies and motions should be an Argument prevalent to perswade that the Earth moves about the Sun Whereas that Hypothesis which shews how to salve the appearances by the rest of the Earth and the motion of the Heavens seems generally so plausible that none of these can resist it Now though it may be said 'T is not only those but great Geometricians Astronomers and Philosophers have also adhered to that side yet generally the reason is the very same For most of those when young have been imbued with principles as gross and rude as those of the Vulgar especially as to the frame and fabrick of the world which leave so deep an impression upon the fancy that they are not without great pain and trouble obliterated Others as a further confirmation in their childish opinion have been instructed in the Ptolomaick or Tichonick System and by the Authority of their Tutors over-awed into a belief if not a veneration thereof Whence for the most part such persons will not indure to hear Arguments against it and if they do 't is only to find Answers to confute them On the other side some out of a contradicting nature to their Tutors others by as great a prejudice of institution and some few others upon better reasoned grounds from the proportion and harmony of the World cannot but imbrace the Copernican Arguments as demonstration that the Earth moves and that the Sun and Stars stand still I confess there is somewhat of reason on both sides but there is also something of prejudice even on that side that seems the most rational For by way of objection what way of demonstration have we that the frame and constitution of the World is so harmonious according to our notion of its harmony as we suppose Is there not a possibility that the things may be otherwise nay is there not something of probability may not the Sun move as Ticho supposes and the Planets make their Revolutions about it whilst the Earth stands still and by its magnetism attracts the Sun and so keeps him moving about it whilst at the same time ☿ and ♀ move about the Sun after the same manner as ♄ and ♃ move about the Sun whilst the Satellites move about them especially since it is not demonstrated without much art and difficulty and taking many things for granted which are hard to be proved that there is any body in the Universe more considerable then the Earth we tread on Is there not much reason for the Hypothesis of Ticho at least when he with all the accurateness that he arrived to with his vast Instruments or Riccioli who pretends much to out-strip him were not able to find any sensible Parallax of the Earths Orb among the fixt Stars especially if the observations upon which they ground their assertions were made to the accurateness of some few Seconds What then though we have a Chimera or Idea of perfection and harmony in that Hypothesis we pitch upon may there not be a much greater harmony and proportion in the constitution it self which we know not though it be quite differing from what we fancy Probable Arguments might thus have been urged both on the one and the other side to the Worlds end but there never was nor could have been any determination of the Controversie without some positive observation for determining whether there were a Parallax or no of the Orb of the Earth This Ticho and Riccioli affirm in the Negative that there is none at all But I do affirm there is no one that can either prove that there is or that there is not any Parallax of that Orb amongst the fixt Stars from the Suppellex of observations yet made either by Ticho Riccioli or any other Writer that I have yet met with from the beginning of writing to this day For all Observators having hitherto made use of the naked eye for determining the exact place of the object and the eye being unable to distinguish any angle less then a minute and an observation requisite to determine this requiring a much greater exactness then to a minute it doth necessarily follow that this experimentum crucis was not in their power whatever either Ticho or Riccioli have said to the contrary and would thence overthrow the Copernican System and establish their own We are not therefore wholly to acquiess in their determination since if we examine more nicely into the observations made by them together with their Instruments and wayes of using them we shall find that their performances thereby were far otherwise then what they would seem to make us believe The Controversie therefore notwithstanding all that hath been said either by the one or by the other Party remains yet undetermined Whether the Earth move above the Sun or the Sun about the Earth and all the Arguments alledged either on this or that side are but probabilities at best and admit not of a necessary and positive conclusion Nor is there indeed any other means left for humane industry to determine it save this one which I have endeavoured to make and the unquestionable certainty thereof is a most undenyable Argument of the truth of the Copernican Systeme and the want thereof hath been the principal Argument that hath hitherto somewhat detained me from declaring absolutely for that Hypothesis for though it doth in every particular almost seem to solve the appearances more naturally and easily and to afford an exceeding harmonious constitution of the great bodies of the World compared one with another as to their magnitudes motions and distances yet this objection was alwayes very plausible to most men that it is affirmed by such as have written more particularly of this subject that there never was any sensible Parallax discovered by the best observations
of this supposed annual motion of the Earth about the Sun as its center though moved in an Orb whose Diameter is by the greatest number of Astronomers reckoned between 11 and 12 hundred Diameters of the Earth Though some others make it between 3 and 4 thousand others between 7 and 8 and others between 14 and 15 thousands and I am apt to believe it may be yet much more each Diameter of the Earth being supposed to be between 7 and 8 thousand English miles and consequently the whole being reduced into miles if we reckon with the most amounting to 120 millions of English miles It cannot I confess but seem very uncouth and strange to such as have been used to confine the World with less dimensions that this annual Orb of the Earth of so vast a magnitude should have no sensible Parallax amongst the fixt Stars and therefore 't was in vain to indeavour to answer that objection For it is unreasonable to expect that the fancies of most men should be so far streined beyond their narrow dimensions as to make them believe the extent of the Universe so immensly great as they must have granted it to be supposing no Parallax could have been found The Inquisitive Jesuit Riccioli has taken great pains by 77 Arguments to overthrow the Copernican Hypothesis and is therein so earnest and zealous that though otherwise a very learned man and good Astronomer he seems to believe his own Arguments but all his other 76 Arguments might have been spared as to most men if upon making observations as I have done he could have proved there had been no sensible Parallax this way discoverable as I believe this one Discovery will answer them and 77 more if so many can be thought of and produced against it Though yet I confess had I fail'd in discovering a Parallax this way as to my own thoughts and perswasion the almost infinite extension of the Universe had not to me seem'd altogether so great an absurdity to be believed as the Generality do esteem it for since 't is confessedly granted on all hands the distance of the fixt Stars is meerly hypothetical and not founded on any other ground or reason but fancy and supposition and that there never was hitherto any Parallax observed nor any other considerable Argument to prove the distances supposed by such as have been most curious and inquisitive in that particular I see no Argument drawn from the nature of the thing that can have any necessary force in it to determine that the said distance cannot be more then this or that whatever it be that is assigned For the same God that did make this World that we would thus limit and bound could as easily make it millions of millions of times bigger as of that quantity we imagine and all the other appearances except this of Parallax would be the very same that now they are To me indeed the Universe seems to be vastly bigger then 't is hitherto asserted by any Writer when I consider the many differing magnitudes of the fixt Stars and the continual increase of their number according as they are looked after with better and longer Telescopes And could we certainly determine and measure their Diameters and distinguish what part of their appearing magnitude were to be attributed to their bulk and what to their brightness I am apt to believe we should make another distribution of their magnitudes then what is already made by Ptolomy Ticho Kepler Bayer Clavius Grienbergerus Piff Hevelius and others For supposing all the fixt Stars as so many Suns and each of them to have a Sphere of activity or expansion proportionate to their solidity and activity and a bigger and brighter bodied Star to have a proportionate bigger space or expansion belonging to it we should from the knowledge of their Diameters and brightnesses be better able to judge of their distances and consequently assign divers of them other magnitudes then those already stated Especially since we now find by observations that of those which are accounted single Stars divers prove a congeries of many Stars though from their near appearing to each other the naked eye cannot distinguish them Such as those Stars which are called Nebulous and those in Orion Sword and that in the head of Aries and a multitude of others the Telescope doth now detect And possibly we may find that those twenty magnitudes of Stars now discovered by a fifteen foot Glass may be found to increase the magnitude of the Semidiameter of the visible World fourty times bigger then the Copernicans now suppose it between the Sun and the fixt Stars and consequently sixty four thousand times in bulk And if a Telescope of double or treble the goodness of one of fifteen should discover double or treble the said number of magnitudes would it not be an Argument of doubling or trebling the former Diameter and of increasing the bulk eight or twenty seven times Especially if their apparent Diameters shall be found reciprocal to their Distances for the determination of which I did make some observations and design to compleat with what speed I am able But to digress no further This grand objection of the Anti-copernicans which to most men seem'd so plausible that it was in vain to oppose it though I say it kept me from declaring absolutely for the Copernican Hypothesis yet I never found any absurdity or impossibility that followed thereupon And I alwayes suspected that though some great Astronomers had asserted that there was no Parallax to be found by their observations though made with great accurateness there might yet be a possibility that they might be mistaken which made me alwayes look upon it as an inquiry well worth examining first Whether the wayes they had already attempted were not subject and lyable to great errors and uncertainties and secondly Whether there might not be some other wayes found out which should be free from all the exceptions the former were incumbred with and be so far advanced beyond the former in certainty and accurateness as that from the diligent and curious use thereof not only all the objections against the former might be removed but all other whatsoever that were material to prove the ineffectualness thereof for this purpose I began therefore first to examine into the matter as it had already been performed by those who had asserted no sensible Parallax of the annual Orb of the Earth and quickly found that whatever they asserted they could never determine whether there were any or no Parallax of this annual Orb especially if it were less then a minute which Kepler and Riccioli hypothetically affirm it to be The former making it about twenty four Seconds and the latter about ten For though Ticho a man of unquestionable truth in his assertions affirm it possible to observe with large Instruments conveniently mounted and furnished with sights contrived by himself and now the common ones for Astronomical Instruments to the accurateness of
stones by an Engine for gauging of Glass Tools or grinding glasses by an Automaton in all which cases there is need of a constant and equal supply of water and sand as also for washing and Fulling of Cloth it may also serve for various sorts of Clepsydras or measuring the quantity of time by the quantity of the current of water as I shall by and by shew And thirdly for maintaining any slow and constant motion as that of a Jack or Clock an Engine for continually stirring of a liquid body or shaking tumbling and turning of dry Solids and powders of which sort there are a great number of uses in Chymistry for the operations of Digestion Calcination Pounding Grinding Trituration Searcing and the like which operations being certainly evenly and constantly performed by an Engine supplied by such a stream of water will far exceed the same kind of work done by the hands of men especially in such operations where the Labour and Diligence is to last divers days and nights together without any intermission which are Requisites not at all strange to Chymistry and which will weary the diligence of the best Laborant and his Attendants A third effect performable by these Poises is the making a perpetual and constant stream in imitation of that of a natural Spring or Fountain in the Earth This may be done if the Cistern be once in twenty four hours recruted and supplied with a new access of water from some Pipes which is usual enough here in London and elsewhere where there are Waterworks and Conveyances of water For as the wasting of the water in the Cistern does no ways abate or diminish the stream of the water from the Cistern so the new access of other water for a supply to refill the Cistern does not at all accelerate it but the stream remains equal And hence consequently constant and as it were perpetual A fourth effect is the delivering any quantity of water to any degree of swiftness and the whole quantity of the water by the same degree This is performed by tapping the Cistern at any part of the depth thereof for according as the Vessel is tapp'd lower under the Surface so will the motion of the water be swifter and here the depths must be in a duplicate proportion to the Velocity desired As for instance the Cistern being tapped with a hole of a quarter of an Inch bore at the depth of an Inch below the Surface is found to deliver a certain quantity of water in a minute if it be desired that through a Tap of the same bore there should be delivered twice that quantity the Cistern must be tapp'd at four Inches deep and if thrice that quantity in the same time it must be tapp'd at nine Inches deep and so forwards as is already demonstrated by Mersennus and other Authors For since the pressure of Fluids upon the parts thereof increase in the same proportion with the depth below the Surface And since the forces requisite to accelerate motions must always be in duplicate proportion to the Accelerations it follows that the perpendicular depths of the Tap under the Superficies of the water must be always in duplicate proportion to the Velocities required The plainness and certainty of this truth in Hydrostaticks long since so fully and excellently demonstrated by Stivinus of all Fluids and so highly improved of late in the particular applications thereof by many more modern Authors who have writ most learnedly and clearly thereof as well as experimentally and practically makes me much admire at the learned Doctor More who in his Enchiridion Metaphysicum in the 11 12 and 13 Chapters and in a Book newly published called Remarks upon two late ingenious discourses c. does not only deny this Gravitation in the parts of Air but of Water quicksilver and other Liquors And instead thereof to solve the Phenomena would introduce into the World a Principle which he terms an Hylarchick Spirit which at command acts and performs whatsoever is necessary to solve all the Phenomena of Mechanical Hydrostatical and in a word all Physical motions and effects In answer to whose Doctrine about Hydrostaticks I shall only urge this one Experiment of the Velocity of the current of Fluids tapp'd and running at several depths under the Superficies of that Fluid which can no ways be solved by the Hylarchick Spirit and we must be fain to come to the Mechanical and plain Rules of motion and to allow every particular of that Fluid to press with its own gravity where ever placed And this I will prove from his own words in his Enchiridion Metaphysicum pag. 113. where explaining very ingeniously the Hypothesis of Gravitation of the parts of Fluids one upon another by the similitude of six men standing in a Line and pressing against a Wall which men he marks with A B C D E F and the Wall with G He says that A the first man cannot press F the last against the Wall G but by pressing B against C and C against D and D against E and E against F nor can A press B against C nor C press D against E nor E press F against the Wall G but at the same time it must be understood that B presses D towards F and D presses F towards the Wall G for A C and E says he are here put for Des Cartes Materia Coelestis pressing the parts of the water within the pores and B D and F for those parts of the water pressing the bottom of the Vessel But says he that B presses D and D presses F appears from this that casting out E and F D doth run to the Wall G and casting out C D E and F B also will run to the said Wall And so says he the state of the matter would be if Gravity did proceed from the meer Mechanical motion imparted to the Terrestrial parts of the Fluid by the Materia Coelestis of Des Cartes to wit the Elements would actually gravitate in their proper places But since there is no such thing it is a sure sign that Gravity doth arise from a higher cause which higher cause he elsewhere supposes to be an Hylarchick Spirit This from so plain reasoning is a strange Conclusion and contrary to all experience Now though I confess I suppose Gravity to be otherwise performed than as Des Cartes has supposed yet do I believe his Suppositions so Rational and Ingenious and so much above the Objections brought against them and so much better than any other I have yet met with as no wise to deserve to be esteemed foeda deliria as the learned Doctor is pleased to term them pag. 125. It shall not be my business to defend Des Cartes Principles at the present nor to set up any new Hypothesis instead thereof but only to urge this Experiment of the running of a Liquor swifter and swifter according as the hole through which it runs is deeper and deeper placed
Pulse it is propagated to 4 below c before the other side of the Pulse touches the Superficies at d the Pulse therefore 44 55 66 c. becomes Oblique to the tendency of the Radiation and by the Superficies ef it is reflected by 77 77 77 till it touches the second refracting Superficies g h where it is observable that the same side of the Ray that entred first the Superficies c d enters first into the Superficies g h in the same manner as if it had proceeded on by the straight Lines f m e l till it met with a Parallel Superficies l m to the first c d for the Ray between the two Parallel Lines f h e g hath the same inclination and respect to the Refracting Superficies h g that the Ray between f m and e l would have to the Superficies m l supposing there were no Reflecting Superficies at e f. I shall not need I hope more particularly to demonstrate every part of this Explanation the very observing the Delineation of the Scheme being enough to make it plain to any one never so little versed in Geometry from which he will plainly perceive that what I endeavour to demonstrate was really so and that I did understand what scope my Demonstration aimed at so far as to hit the Mark which was to shew that Colours were generated where according to Des Cartes own Principles there could be no Rotation of the Globuli Now though the Learned Doctor would not admit of this Demonstration to be sufficient to do the work yet he says Pag. 252. Veruntamen dissimulandum non est non pauca me meapte opera excogitasse quibus pro persuasissimo habeo eorum motus rotationes modis pure mechanicis semper fieri non posse And in prosecution of the destruction of this Rotation of the Globuli which he hath hitherto seemed to defend he adds four several Arguments I shall not now stay to repeat them But whosoever will please to read what the Learned Doctor hath suapte opera excogitated against the Cartesian Hypothesis and set down in the 252 253 254 and 255. pages And compare them with what I have said in the forementioned place to wit at the latter end of the 60. and the beginning of the 61. pages of my Micrographia may plainly find the Arguments brought by the Doctor do very little if at all differ from those I there published I could heartily therefore have wished that the Learned Doctor had made use of some other Mediums to prove the Existence of an Hylarchick Spirit and not have medled with Arguments drawn either from Mechanicks or Opticks for I doubt that such as understand those subjects well will plainly see that there is no need of any such Hylarchick Spirit and if there be no need of it but that all the Phenomena may be done without it then it is probable that there is none there for Natura nihil agit frustra It had been much easier to have proved the existence of it by Arguments drawn from subjects we less perfectly understand as from the generation nutrition vegetation and propagating of Vegetables and animal substances for there the manner of the progress of Nature being infinitely more curious and abstruse and further removed beyond the reach of our senses and understandings one may more boldly assert strange things of this Hylarchick Spirit without fear of controul or contradiction and from whence possibly it may never lie within the power of Reasoning to banish him But to leave this Digression and return to the use of these water-poises A fifth effect may be for washing and refining of Earth Clays Powders and the like the clear water by these contrivances being made to run over gently at the top and so leaving all the settlement from the water at the bottom By any one of these with a receptacle Cistern added to it the stream of water from that Cistern may be accelerated or retarded by any degrees desirable This doth depend partly from the proportion of the Tap of the Receptacle Cistern to the Tap of the counterpoised Cistern and partly from the shape and make of the Receptacle Cistern by the proportion and shape of which the stream of Liquor through the Tap of the Receptacle Cistern may be modulated at pleasure as any one a little versed in Hydrostaticks will easily perceive and demonstrate A sixth effect may be for governing the heat of Lamps for Distillations Digestions Fermentations Putrefactions Dissolutions hatching the Eggs of Birds or Insects accelerating and seasoning or timing the growth of Plants nealing of Glasses and Metals by the gradual access of the heat so as to make them fit for stronger degrees or by the gradual recess to bring them out of the greater degrees to make them tough and capable to receive the cold of the Air. It would be too long to give instances of contrivances for every of these operations but the skilful Mechanist Philosopher or Chymist will easily supply his own desires by some one of these I have instanced in or at least by a composition of them I shall therefore only add a description of a Clepsydra or time-keeper or two and so leave this subject for the present A description of a new sort of Clepsydra THis contrivance is nothing else than that Two of the second sort of Vessels are so contrived as to run into each other and to empty themselves and be filled alternately and their bigness or capacity and the hole through which the Liquor is vented are so proportioned as to be emptying the space of an hour which is easie enough and may be adjusted to what accurateness is desired Then the convex Superficies of the Cylindrical poise is divided into sixty equal parts by straight Lines drawn upon its Surface Parallel to the Axis and to each other these lines by the sinking or turning of the said poise denote the minutes and if smaller Divisions of time be desired the spaces between them may be divided by other smaller Parallel Lines denoting the parts of each minute to what niceness is desired One of these Cylindrical Receptacles may be fixt and the other by an easie apparatus may be made to rise a little when it is top-full and fall a little when quite empty below the Level of the other that is fixt The Chanel between them through which the water is to run out of the one into the other may be a small pipe with a hole in it of a bigness proportioned as I said above to let the Liquor run out of one into the other in the time desired and its ends may be fastned to the two Receptacles by a part of the neck of a bladder or gut so that it may be limber and may always have a Declivity into the Vessel that is to be filled the Declivity need not be above half an Inch. The Liquor used in it may be Water Oyl or any other Liquor that doth not easily evaporate But
the best of all is Quicksilver because it doth not with keeping evaporate at all sensibly which I have carefully observed for these fifteen years last past Nor doth it grow thick or foul by the alteration of the Air nor do I find it sensibly alter by the heat and cold at lest not comparable to the great changes which other Liquors suffer by the alterations of those qualities It is an excellent material for measuring time in a standing Machine and there may be hundred of ways contrived to make it measure the space thereof as accurately as a Pendulum and I have many times admired that Tycho Brahe who was otherwise so curious and exact in the contrivance and make of his Engines and Instruments was yet so defective in his contrivances of measuring time by Quicksilver when there were so many obvious and easie ways of doing it as he seems to complain in his works I have made trial of several with very good success and found some of them even beyond expectation certain of which I may hereafter upon an other occasion add the descriptions when I publish the various ways of making exact Time-keepers or Watches In the mean time being now speaking of Time-keepers for variety sake I shall mention A New Principle for Watches THis is a way of regulating both standing Watches and movable Watches either for the Sea or the Pocket which some ten or twelve years fince I shewed the Royal Society when I shewed them my contrivances of the Circular Pendulum which is since published by Monsieur Hugenius which is also mentioned in the History of the said Society p. 247. lin 20. This was by a fly moving Circularly instead of a ballance whose motion was regulated by weights flying further and further from the Center according as the strength of the Spring of the Watch had more and more force upon its Arbor The Weights were regulated from flying out further than they ought to do by the contrivance of a Spiral Spring drawing both the said Weights to the Center of the motion or fly in the same proportion as I then demonstrated Gravity to attract the weight of a Circular Pendulum moved in a Parabolical Superficies towards the Center or Axis of its motion The Weights were so contrived as always to counterpoise each other The Skeleton of this fly you have represented in the Figure The particular explanation of the parts and the Geometrical Demonstration of the Principle both of the Springs and of the flying from the Center I shall explain in the Theory of Springs and in the description of Time-keepers and Watches 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 Arist Quaest Mechan An Observation about the Seed of Moss SInce the publishing of my Micrography I have met with an Observation which though it be of one of the smallest compound bodies I have hitherto taken notice of yet does it afford a hint of very great concern in Natural Philosophy And it does seem to make clear the cause of a Phaenomenon that hath appeared dubious not only to me but to many other more knowing Naturalists I have often doubted I confess whether Moss Mushroms and several other small Plants which the Earth seems to produce 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 were the off-spring of a Seed or Grain and I have been apt to believe that they were rather a secondary production of Nature being somewhat the more inclined to that opinion because having formerly examined the small knots or Seed-cods of Moss with a single Microscope I could not perceive any thing in them that I could imagine to be Seed at least not so great a quantity as seemed necessary to maintain so numerous a Progeny as was every where to be found of it that which then came out of them seeming to be rather a pulp or pith than any thing like the Seeds in other similar Cods But being since somewhat more inquisitive I did examine several of the above-mentioned Knobs or Seed-vessels and found that there were seeds in them no less wonderful for the greatness of number than the smalness of bulk Taking then some of the ripe and brown or reddish ones of them and pressing them pretty hard I found that there was a small dust went out of them which seemed to vanish into the Air. Pressing and squeezing others of these upon a black-plate and examining the powder with a Microscope I found it to be a great heap of exceeding small Seeds Globular and pretty transparent It is the smallest I confess I have yet seen and it may be that has hitherto been discovered And unless that be a plant which I discovered growing on the blighted leaves of Roses and that those small bodies be seed vessels or unless those Knobs I have discovered on the top of mould be the like I cannot presently imagine where there should be found a smaller For I find that there will need no less than thirty six hundred of them to be laid one by another in a line to make the length of an Inch and to cover the Superficies of an Inch-square there will need no less than nine hundred and threescore thousands besides twelve millions of single Seeds if laid quadrangularly but if laid triangularly there will need no less than two hundred and fourscore thousand besides seventeen Millions of single grains And the number in a grain weight of them cannot be less than one thousand three hundred eighty two Millions and four hundred thousand single grains about eighty of these square Superficies of Seeds being laid one upon another in the Trigonal order making as near as I can guess the thickness of a piece of fine Paper a square Inch of which weigheth a grain And though this may seem a most incredible narration yet I would desire such as are apt to be too censorious to take the pains to gather a few of these Seed-vessels and examine them as I have done and then speak what they find and believe no more than their own sense and reason will inform them and they may easily see that what I have asserted will be rather short of than exceed the real numbers Now if this Shell of the Seed be thus small how much smaller must needs be the rudiment of the Plant that lies enclosed within it And how easily may such Seeds be drawn up into the Air and carried from place and place even to the tops of the highest Towers or to places most remote and be sowed by the passing Air or falling drops of Rain on the boughs or branches of Trees sides and tops of Walls Houses or Steeples And it is not in the Art of man to leave Earth exposed to the common Air and to exclude the entrance or prevent the sowing of these imperceptible Seeds and therefore it is not to be wondred at that if any earth though never so pure be exposed to the Air and Rain though at the top of a Steeple it will produce Moss Further inquiry may possibly instruct us that there
toward the Sun evenly defin'd Encompassed with a fluid yielding to motion but dissolving its parts It s light from its self 9. It s Nucleus supposed dense possibly as the middle part of the Earth of which some conjectures Dissolved by the Aether as in our Atmosphere 10. Argument for the looseness of the central parts of the Earth from the variation of magnetical direction 11. The Nucleus of Comets possibly the same Internal motion may weaken gravitation Parts separated may be agitated by the gravitation of the ☉ Tail made not so much by the particles receding as the Stars approaching the Sun 12. How the Comet may first lose its Orb in the Universe and passing through the spheres of Activity of several central bodies is deflected and attracted by them and the Blaze raised to a prodigious length 13. The bodies being attracted by some gravity Blaze expelled by levity explained by smoke and steams Somewhat for positive levity 14. A digression concerning the method of speculating the great and first principles of the Universe The Coma and Blaze like smoke or flames 15. Shining particles a shining point not a line of light Considerations and Experiments about the ways light is augmented by as by swift motion adjacent dark medium Flame explained Why the Particles coalesce into a stream 16. Enquiry about the magnitude and place of Comets Many supposed them sublunary Tycho and Kepler proved them coelestial How far we may rely upon Observations for Parallax Parallax and its effects described 18. Tycho supposed the Comet of 1577. to move about the Sun Kepler that of 1607. to move in a straight line that of 1664. had no sensible Parallax by what means it was found 19. Refraction in this way varies little Theory of Comets defective as to Parallax hitherto Parallax not to be enquired from the Observations of several men Errors creep in from the Press and the Graver as in P. Gottignies Plates 20. Nothing to be concluded from Observations made by persons in differing places for want of accurate Instruments and Observations 21. Even the best as Hevelius Gottignies Petit or Auzout err Some reason for this assertion Most of the rest altogether insignificant 22. Want of Observers Instruments and Tables the cause How these wants are to be supplied What the world expects from Mr. Hevelius 23. And of how great use his Tables and Projections made by them will be Parallax from diurnal motion failing 24. Other Parallaxes arising from other hypotheses of the proper motions either of the Earth or Comet or both together considered arise to a certainty 25. Others depending upon other suppositions define nothing of the magnitude or distance of Comets The inconvenience of Tycho's and also of Kepler's Hypotheses explained A third way I have taken What consequences follow from it 26. As that it moves in a Circle that comes within the Earth Orb in ♌ and without ♃ Orb in ♒ a sextant in 130 days c. This not relied on because there may be other hypotheses to solve the phaenomena as that the Earth is unmoved and the Comet moved in a Circle whose convex side is toward the Earth 27. This hypothesis explained by the sixth figure 28. The distance and bigness of the Circle of the Comet undeterminable this way without a diurnal parallax since the appearances may be solved by Circles of any bigness proved by the eighth figure 29. Allowing inequality of motion or more compound curve lines nothing can be determined The circular Orb it seemed the most probable solves Kepler's acceleration according to the increase of a line of Tangents 30. A gravitation towards the Sun makes out the motion of the Comet and Planets and of the Blaze The Blaze explained by experiment of ♂ dissolved in oyl of Virt. 31. This experiment and hypothesis farther explained and applied to explain the Blaze which is from thence bent brighter on one side than the other not direct from the Sun 32. Cometical body and motion as old as the world yet wasting in the Aether explained by fire Dissolution by menstruums 33. Thence the proprieties of Comets conjectured and the sum of the foregoing discourse repeated being the end of a Lecture Recourse to Tycho Brahe's Observation 34. for making out the Comets Orb. His supposing its motion unequal without reason a shift Mr. Horrox his hypotheses in the ninth figure a product of chance 35. A discourse on it and some objections against Tycho's 36. Kepler's hypothesis examined by these Observations of Tycho's found the most likely but with some alteration Line of Trajection bent a little Motion accelerated towards the Sun retarded from it 37. The swifter and further off the Comet from the Sun the less the bend explained by the tenth figure 38. The way of enquiring parallax by Telescopes 39. further explained A second way by two Observers in distant places propounded The third way of Sir Chr. Wren his Majesties Surveyor-General 40. Set down and demonstrated by a Geometrical Problem 41. How exactly all those Observations he had were made out by it together with his own Schemes both which I had in the beginning of Feb. 1664 5. 42. Some other Papers about Comets added being reflections on Mr. Descartes and Kepler's hypotheses from particular tracings of the Comets of 1664. and 1665. A Scheme of the later Observations of that of 1664. added and some reflections being all the papers could be found about those Comets 43 44. Animadversions on this of April last Why the former conjectures were adhered to concerning the light of Comets 45. Several sorts of shining bodies enumerated 46 To which the light of the Comet seems to have most affinity and how produced 47. Further described and explained 48. The reason of its parabolick figure demonstrated from the proprieties of motion from or toward a gravitating body as the Sun 49. Concerning the wasting and lasting of the Cometical body The bigness and nature of the Particles that compose the Blaze 50. Some difficulties in this supposition concerning the action of the Aether in levitation and ascent dissolution shining c. cleared and explained by Experiments 51 52 53. But would have been further examined by Observation if there had been opportunity 54. That these assertions about the light of Comets may not seem too paradoxical some further Considerations and Observations about light are added and some new ways propounded 55 56. Mr. Boyle's Memorial concerning a Phosphoros written for his own use inserted in which he first names the Author of it and describes his Apparatus 57 58. Then the observables 1. Two spoonfuls of matter enlighten a large glass sphere 2. A little enlightens a large Cylinder 3. Liquor shaken had a smoke and flasht 4. A dry substance affirmed to have continued shining 2 years flashed 59. 5. Some dust of this on a Carpet twinckled like Stars Writing on paper with it shin'd and smelt of Sulphur and Onions 60. 7. The hand on which it was rubbed shin'd but felt no
each of the shining parts of the Comet seems to fill and occupy a much greater space than really it doth and so as 't is observable in the milky way a great number of these small shining bodies though dispersed at a pretty distance one from another yet by reason of the imperceptibleness of each of them they all seem to coalesce into a stream or Blaze of light the brightness of which is yet farther augmented by a clear and unenlightened air and by such a part of the Heaven wherein there appears fewest of the Stars whether they be greater or lesser To the Query Of what magnitude the Body Coma and Blaze of Comets may be No answer can be given until another question be first answered and that is What is the place of Comets and what is their distance from the Earth It was the opinion of most Modern Writers before Tycho Brahe and Kepler I know divers of the Antients thought otherwise that Comets were sublunary Meteors drawn up into the higher Regions of the Air and there set on sire and so continued burning till the Meteor were consumed and as the matter increased or wasted so did the appearance of the Comet But this noble Dane and several others about that time found by accurate observations made that its Parallax was less than that of the Moon and consequently that it was farther distant from the earth that it must be a body of another magnitude and nature than most before that time had imagined and therefore that it ought to be otherwise thought of than the generality of mankind believed concerning it Many had been the attempts of former Writers concerning them to find out their parallax and whether from their unaccurate instruments or from their less skill and diligence in using them or from an imagination of the solidity and impenetrability of the Coelestial Orbs or from error in their calculations or from comparing Observations made at distant places one or both whereof were unaccurate or from a prepossession of Tradition or common Fame or from what other cause soever it were is uncertain but 't was generally concluded by them that all Comets were sublunary Meteors and there are not even at this day wanting some of the same opinion though for what reason I know not 'T will be hard to convince some of these that the opinion they have hitherto received for good is not so because they will hardly give themselves the trouble of examining strictly into the matter And to understand the nature of Parallaxes and how significant they are in determining the distances of bodies from the surface of the Earth to certain degrees thereof beyond which by reason of the imperfections in Instruments and Observations and the exceeding niceness and curiosity necessary they signifie very little It is not my present design to explain what Parallax is that I would suppose my Reader to understand otherwise there can be no reason shewn him to convince him that 't is possible to prove that this or that Comet was not nearer than so many semidiameters of the Earth nor farther off than so many There are then two ways by which we may come to some certainty of what distance a Comet is and those are first the Parallax of its Diurnal motion or its Parallax caused by the Diurnal motion of the Earth And secondly the Parallax of its proper motion compared with the Periodick or Annual motion of the Earth The first of these may be observed two ways either by two Observers at parts of the Earth very far distant from each other but as near as may be under the same Meridian as suppose the one in London the other in St. Helens both conspiring in their observing of the place of the Comet amongst the fix'd Stars at the same time Or secondly by one Observer in the same place by observing the place of it amongst the fix'd Stars in its rising or setting and in a greater or if it may be its greatest height The noble Tycho by very accurate Observations of the Parallax proves the Comet of 1577. to be above the Moon Kepler by his own Observations proves that of 1607. at its beginning to be four times farther distant and I doubt not but some may have been above forty times farther But I do not yet find that any Observations have accurately determined that which is indeed the great help by which we are inabled to judge of the nature and all the other accidents and proprieties of Comets The Aristotelian Philosophy for a long time prevailing made the world believe them to be nothing but Exhalations from the Earth drawn up into the higher Regions of the Air. But Tycho by his Observations of their Parallax raises them out of that confinement but yet he seems to place them in an Orb about the Sun But Kepler frees them from that confinement and assigns them the Universe to expatiate in But none of all these do accurately prove the true distance of them their Parallax being for the most part so very small that I fear Instruments with common lights will hardly reach them But we must expect from future observations made with Telescopical Instruments to receive a certain Answer to this Query Certain I am that the Comet which began to appear in November 1664. and disappear'd in March following was far removed beyond the distance assigned by Kepler For by my own Observations divers times repeated I could not find any senfible Parallax though I endeavoured by a new method to make my Observations more accurate Now though I had not the convenience of making use of a Quadrant or any such Instrument to observe its place when near the Horizon yet the way I took would I think be as good which was this With a very good six foot Perspective-glass or Telescope I observed the place of the Comet in respect of the adjacent small Stars as soon as it appeared and so traced its way till it disappeared in the vapors of the Horizon the like I did several other days successively taking notice by what degrees in what times it made its progress to see whether by its Parallax when near the Horizon it would have been deprest below that line of its motion which it kept when at a greater height above it But though I tried this several times yet I was not able to discern that the Parallax of it caused either any sensible bending of the line or any sensible inequality in its progress by which I should have sooner found it than by taking its altitudes with common Instruments though I confess these Observations were made when the motion of the Comet was slow and consequently when in probability it was far distant from the earth To me there seems no doubt but that it was a long way removed above the Moon when I made these Observations for had it been of an equal distance with that they allow the Moon it must this way have manifested a very sensible
it But as to the third I hope the indefatigable labour and skill of Monsieur Hevelius will shortly supply the present defect though it had been much to be wish'd that the Instruments he had made use of had been fitted with Telescopical sights These Tables if well done will alone as to the business of Comets at least supply the place of all other Instruments almost save only a thread especially if they be so delineated in Tables after the Tangent projection as that the minutes of every degree may be very distinguishable which will not swell the Maps of the Heavens into an extraordinary large volume and may possibly be the cheapest Instrument for this purpose an Astronomer can be furnished withal for having such a volume of Tables it will be very easie with a thread and one's eye screen'd only with a spectacle made of a thin plate of Brass with a small hole through it instead of a glass to observe what place the Comet possesseth amongst the fixt Stars for having by the help of the said thread observed what two Stars lie in the same line with the Comet on one side of it and what other two Stars lie in a line with it which is at right angles as near as may be with the former line by finding out those four Stars in the Tables ordered according to the Tangent projection and with a Ruler drawing lines over them respectively where those lines do intersect there will be the true place of the Comet from which it will not be difficult to find out the true Longitude and Latitude of it by a Sector with Tangents Now as these Tables of all the fixt Stars visible to the naked eye would serve for finding its place whilst very big and swift of motion so the like Tables of the small Telescopical Stars that lie near its way when almost disappearing and moving very slow will by the help of a pair of measuring Compasses placed within the eye-glass of the Telescope and a straight line or hair drawn cross it serve to find the true motion and way of it when only visible with a Telescope according to which method I made the annexed Schemes and Observations of the last appearances of the Comet Now since neither from my own nor from any other Observations that I have hitherto met with there can be any certain conclusion drawn of the distance of these Comets save only this that their distance was very great and much higher than the body of the Moon because else there must have been a considerable Parallax caused by the Diurnal motion The next enquiry will be what other ways there are of knowing its distance Now though none could be more demonstrative than the Parallax found this way by the Diurnal motion yet there are some other which seem more easie arising from the consideration of the motions that may be thought to be concern'd in the producing the appearances And though they be wholly hypothetical and so need some other arguments to prove the ground and principles on which they are founded yet since there are not very many considerable ones wanting to make them probable and rational I shall here add somewhat of my inquiries after the distance position motion magnitude c. of these Comets by these means Of these ways there are several depending upon several suppositions which produce very differing effects as to the magnitude distance motion and way of the same Comet The suppositions are these Either that the Earth moves in an annual orb about the Sun as the Sun is supposed by others to move about the Earth Or that the Earth is perfectly fix'd and hath no such motion Next that the Comet moves either in a straight line or in a curve line and the curve is either a circle or some other regular or irregular curve Further that the motion of the Comets in these lines is either by equal or unequal spaces in equal times Now according as we take this or those of these differing suppositions and compound them together so will the product of them be strangely differing Amongst the great variety of compositions of these principles or suppositions these seem the most simple and consequently being any otherwise proved will best determine the true distance and way of the Comet First To suppose the Earth to stand still and the Comet to move equal spaces in equal times in a circle Secondly To suppose the Earth to move in an annual Orb about the Sun and the Comet to move through the Aether or Expansum equal spaces in equal times in a straight line Thirdly To suppose the Earth to move as above in its annual Orb and the Comet also to move equal spaces in equal lines in a circle The other are indeterminate and infinite and nothing can be concluded from them as to the distance magnitude motion c. of Comets for the line or way of the Comet may be placed at any distance if we will suppose it moved in an uncertain curve with unequal degrees of velocity And indeed upon a supposal of an inequality of motion nothing of its way or distance can by any of these suppositions be found out This fault had that of Tycho Brahe where he supposed an unequal motion of it in its Orb about the Orb of Venus which was founded upon the first Hypothesis but had introduced into it some inequality of motion besides his own supposition that it was moved about the Sun and the Sun about the Earth See the fifth Figure Keplers way which was after the second Hypothesis had the same fault for he supposed the annual motion of the Earth and the motion of the Comet in a straight line but introduces an acceleration of motion in the Tangent towards the latter end The third way I have here taken and from the best observation I could meet with I have delineated its respects or angles to the Sun and accordingly supposing it to move equal spaces in equal times in a curve which for so much of it as the Comet was observed to pass was very near a Circle I found this Circle would fall as it is express'd in the seventh Figure where 't is obvious to take notice that when the Comet was nearest to the Earth namely about the 19. or 20. of December that it was not nearer than an eleventh part of the distance of the Sun that on the 23 it was twice as far that on the 29. it was four times as far that on the 15. of January it was as far as the Sun and on the 14. of February it was above twice as far distant as the Sun That this way or Orb of the Comet is here bended so as if it were an entire Circle one part of it would go without the Orb of Jupiter as the other which is here delineated comes within the Orb of the Earth that the plain of this Orb is inclined to the plain of the Ecliptick about 18 degrees that if
the motion of the ascending stream or beard being but slow there needs no very quick supply of other parts We see also into what a vast quantity of smoke a small parcel of a combustible body may be turn'd From all which particulars 't is not unlikely but that the Comet may be a body moved with a regular circular or elliptical motion as the Planets are that it may be a body of such a constitution as that the fluid Aether through which it passes may dissolve it much after the manner as a meâ—struum such as Aquafortis Spirit of Niter c. does a dissoluble body that by this means there may be a slow but continual eruption of somewhat opacous parts which may by their dissolution afford a sufficient quantity of light to make as great an appearance as any of the Comets that this stream or beard may by the resistance of the Aether be a little deflected back wards in the same manner as an ascending stream of smoke will be by the resistance of the Air if the burning body be mov'd this or that way through it that the body of the Comet may be both as ancient and as lasting as the world and that this which has lately appeared may have appeared heretofore and may likewise hereafter appear again that 't is probable the nearest distance of it was much greater than that of the Moon that the length of its Beard was longer than its distance from the Earth and consequently several times longer than the distance between the Earth and the Moon that its visible way among the Stars was very differing from a great circle especially towards the latter end when it became retrograde that its way through the Aether could not be supposed equal in a straight line though it might be supposed equal in a curve or circle that the exact way of it could not be certainly determined by the best Observations I have yet met with and that therefore the best help we have to ghess of its way and distance is by its manner of moving as to appearance among the fixed Stars which I have already shewn to be explicable by various Hypotheses for both the Earth and Comet may be supposed to be moved either both one way or contrary ways or cross ways the Earth may be supposed to stand still and the Comet only to be moved and the like These Requisites therefore being hitherto wanting in the Observations I have met with of this Comet all that can be said of it will at best be but conjectural and hypothetical since nothing can be reasonably built upon those Observations where the truth of them is dubious wanting therefore sound materials to work upon in this Comet I had recourse to the Observations of the noble Dane Tycho Brahe being sufficiently satisfied both of the ability industry and veracity of that excellent Author who left nothing unattempted for the perfecting of such Observations as seem'd to him requisite for the compleating a History of that Comet which appeared in 1577. And from those Observations of his I endeavoured to trace the way of it according to several hypotheses and found that supposing the Earth not to be moved with an annual motion but only a diurnal about its own Axis the way of Comets will fall in a line very near approaching the nature of a circle though neither into an exact circle nor an exact ellipse and therefore seems irregular and not at all probable Again supposing it moved about the Sun as Tycho has done we find from his Calculation of it he was fain to allow it a quicker and slower motion in its Orbit to solve the Phaenomena which seems to me but a shift that will serve to help out any lame Hypothesis whatsoever And that granted and the Parallax of the Comet unknown I will undertake very easily to make out almost any Hypothesis which is the fault also of Mr. Horox his Hypothesis wherein he supposes the Earth to be moved about the Sun and the Comet like a Rocket to be shot out of the Sun and by degrees to return to it again in which Hypothesis indeed there seems to be much more reason for aninequality of motion though not in the manner as he has placed it 't was very rational that the motion of it at first if cast out of the Sun should be very swift but then it ought likewise to have accelerated its motion in the same manner in its return back to it again which it does not in his Hypothesis for a stone or any other heavy body being shot up into the Air does make its return back again to the Earth almost by the same degrees of velocity by which it ascended from it almost I say because the resistance of the Air does so far impede the motion of the body through it that it never suffers it to acquire the same degree of velocity with which it was first shot upward This is sufficiently evident from a Pendulum which if it be thrown upwards and be suffered to return back it will never rise again on the opposite side to an equal height with that it descended from on that side towards which it was thrown but besides in his Hypothesis he seems to take no notice at all of the Latitude of the Comet which seemed to carry it much farther off from the Sun when he supposes it to be returning nearer And indeed upon the whole his Hypothesis seems rather a product of chance than of any contrivance For he in endeavouring to set off the Longitude of the Comet according to Tycho's Tables and to trace its way by supposing the Earths annual motion making use always of the same Radius to set off the aspect or apparent angle of it with the Sun his line of Chords he made use of did always direct the point of his Compasses to the place where he situates the Comet as may be easily found by examining the ninth figure where you may find that he places the Comet always equally distant from the Earth and that distance is always equal to the distance of the Sun which has so many inconveniencies and improbabilities that I shall not insist farther on it especially since I do not find that he bestowed any farther pains in explicating or cultivating this his Hypothesis than only the bare delineation of this ninth figure But to return to Tycho's Hypothesis if that be true why did not the Comet again appear after a certain space of time and why could not he have foretold when it should again appear as well as he could predict the appearance of Venus about whose Orb he supposes it to circulate I shall pass by several other very material objections that might be made against that his supposition because many of them might be made also against his Hypothefis of the Heavens in general which I shall the rather omit because I do not find he has many followers in that supposition the generality of
Astronomers embracing rather the Copernican System especially as it is refined and rectified by the ingenious Kepler Lastly I endeavoured to trace the way of the Comet from Tycho's Tables according to Keplers Hypothesis which was that the appearances of the motion of the Comet were ascribable to two causes namely the motion of the Earth about the Sun in its annual Orbit and the motion of the Comet in a straight line not accelerated according to the proportion of the increase of Tangents but upon supposition that it mov'd equal spaces in equal times for I cannot imagine what reason he had to suppose its motion to be accelerated and much less why he should assert it to be according to the proportion of Tangents which in a little time must necessarily come to move infinitely swift than which nothing is more hard to be granted And I found it after many trials and essays to fall in a straight line inclining to the plain of the Ecliptick by anangle of 47.40 and cutting it in 9 degrees of Scorpio if computed out of the Sun and moved faster by half than the Earth in its Orb and this to so great an exactness to answer all the Observations of Tycho that from a very large Scheme which I drew of it on a plain I could never find many minutes difference so that I concluded that to be the most likely Hypothesis for that Comet it seeming to solve all the several Phaenomena of the motion and magnitude of the Comet with the least imaginable difficulty and to be most agreeable with my physical notions of Comets For first it only supposes a solid body moved in a fluid with an almost direct motion I say almost direct because for some physical reasons as I have said before I imagine it not exactly straight but inflected a little towards the curvity of a circle which I shall presently endeavour to explain farther in this Comet Next it supposes that body to move in that line almost equal spaces in equal times I say almost equal because some of those equal spaces may be increased by an accelerating cause or principle such as that of a gravitation towards the body of the Sun placed in the center of its Vortice or System when the motion of the Comet carries it towards the Sun and may be diminish'd from other impeding causes such as the impediment of the fluid medium through which it passes and the attraction of the Sun operating on it when its motion carries it farther and farther off from it besides 't is not unlikely but that the attraction of the Earth or some of the other Planets may have some kind of influence on it especially when its line of Direction does somewhat nearer approach those attractive points But the deslection from a straight line is always so much the less by how much the swifter the body is moved and by how much the farther off its line of trajection is perpendicularly distant from those attracting bodies According to this supposition of mine I have endeavoured to make out all the appearances of this last Comet taken notice of in the best observations I have yet met with amongst which I find no one of the Parallax satisfactory as in the tenth figure let S represent the Sun O R B the Orb of the Earth A C D E F a bended or curve line in which the Comet is supposed to move the Comet then coming into the Sphere of the attractive power of the Sun by the straight line P A G at A the power of the Sun worketh on it and by degrees attracting it towards its own Center by that time the Comet hath moved to C the attractive power hath deflected its direct course from P A G to C H and so the Comet would continue to move in that straight line C H but it is still deflected so that at D it moves towards I but the gravitation of the Sun attracting it deflects it from that line towards E and so from E to F when it begins again to Jet out of the attractive beams of the Sun and so it will continue to proceed as if it had come to that point by the line M F L the reason of which is the great velocity of these bodies which are generally much swifter in their motions than the Earth or other Planets are supposed to be in theirs We must seek out some other way therefore of finding of the distance of Comets than the commonly used I shall therefore somewhat further explain the contrivance I newly invented for this purpose by which not only the Parallax of the Comet but of the Planets also may be found with great facility and exactness Having a large Telescope prepared as I formerly directed with Eye-glasses capable of taking in an Angle of about two degrees at once and furnished with a dividing Scale observe when the motion of the Comet or Planets is not too fast the position and distances of the small fixed Stars which are next adjoyning to the moved body whose Parallax you would find of these small fixed Stars you shall seldom miss a sufficient number which will be taken into the glass at once if at least the object-glass be allowed a very large aperture and having found such Stars as will be convenient for your purpose be very diligent in taking by the help of the dividing Scale the exact distance of them one from an other and when the body is highest above the Horizon viz. in or near the Meridian by the same means take the exact distance of it from two or three of the nearest and most conspicuous fixt Stars about it and by the help of a plumb-line hung likewise within the cell near the dividing Ruler find exactly the positions of all those bodies you take notice of to the Perpendicular or Horizon which may be easily enough done if together with a Plumb-line or Perpendicular plac'd within the glass you have also a small Diagonal thred fastned to a ring whose circumference is divided into 360 degrees and moveable so as by the finger easily to be turn'd any way by which means this Diagonal thred may be made to cross over any two of the bodies you observe and by observing what division of this divided limb the Perpendicular cuts it will be easie to determine the exact position of those Stars to the Horizon this same may be done by the dividing Scale also if that be fixt in a divided Circle which is movable in the same manner as the thred is supposed to be This Observation with all other circumstances of it is likewise to be repeated at the setting or rising of the Planet or Comet and again the next night when it comes to the Meridian and in each of those observations the exact time is to be noted by a time-keeper and the altitude by some of those I have before described for by comparing these three observations together it will be very easie to find what
Revolution of the body of ♃ upon its Axis I first discovered in May 1664. and published in the first Transaction which was a considerable time before it was discovered by Monsieur Cassini but we are obliged to him for the perfecting the Theory as we are also for many other rare Discoveries and excellent improvements in Astronomy to be 9 hours and 56 minutes is as it were a watch for visibly pointing the hours and minutes to half the Earth at once so that it shews the same time to all under the same Meridian and a different time to different Meridians according as they differ in Longitude It hath for an Index of its motion one principal spot which is very neatly distinguished from the rest of its surface and seems from its figure and situation to have some resemblance to the Caspian Sea of the Terraqueous Globe By the help of good Glasses it may be seen passing the under Hemisphere of it from the East to the West with a velocity so sensible that one may determine to one or two minutes the time that it comes to the middle of the Disc which is the place the most fit for establishing of the Epochas and for finding the difference of Longitude There may be a great number of such Revolutions observed since in one year of 365 days there are made 882 Revolutions But it doth not appear in every year but as if it were some kind of Marish which is dried at certain times and so disappears during two or 3000 Revolutions and after it hath remained thus imperceptible for some years it returns again to its former state After it had been observed the last six months of the year 1665. and some months of 1666. it became invisible till the beginning of the year 1672. then being returned to its former appearance Monsieur Cassini compared the intervals of the six years and limited the revolution to be made in 9 hours 55 minutes 51 seconds and continuing his Observations to the end of the year 1674. he found by these two years that it was too slow by two seconds and a half so that it appeared to be in 9 hours 55 minutes 53 ½ seconds This spot hath been invisible in 1675. and 1676. during which space there happened other very considerable changes in the body of Jupiter for the clear interstice which was between the two dark belts of Jupiter was separated into many little parts in the manner like so many Islands as if the two obscure belts had been two great Rivers broken one into the other and had left these parts which appeared like Islands which yet were at last all effaced and the two dark belts and the interjacent space at length all coalesced into one large belt But after the coming of Jupiter out of the Rays of the Sun in the year 1677. the belts again took their form and situation which they had heretofore to wit the same which is described in the 24 figure The principal spot appeared anew after the beginning of July last Monsieur Cassini found this spot in the middle of Jupiter the night after the eighth of the said month at 13 minutes after one at night and hath hitherto ever since observed it at the hours proper to its revolution Having compared many Observations of this year with as many others made the same days of the year 1665. for avoiding the scruples which may arise from the inequality of times he hath found by the intervals of twelve years that those revolutions compared the one with the other complete themselves in 9 hours 55 minutes 52 seconds and 5 or 6 thirds And because that in the years 1672 1673. they appeared more slow by 2 seconds and a half during the time that Jupiter was in its greatest elevation from the Sun Monsieur Cassini inclines to suppose that these revolutions have some little inequality depending on the variation of the distance of ♃ from the ☉ and that they are a little slower when ♃ is more â—emoved and somewhat faster when nearer approached that body the same which several great Astronomers have supposed to happen to the Diurnal Revolutions of the Earth in the Copernican Hypothesis In this account he hath separated the inequality which doth result from the variation of the two equations of Jupiter as he hath explained in divers Letters in 1665. the which may amount to one half hour besides the inequality of natural days which according to his Hypothesis may amount to 16 minutes For the finding then of the return of the principal spot to the middle of ♃ for many years to half an hour or thereabout there needs nothing but adding still the time of the period to the Epoche of the 8. of July 1677. and for the finding precisely even to some minutes the two inequalities of Jupiter must be observed according to the following Rule Differentiam inter medium locum Jovis apparentem converte in tempus dando singulis gradibus min. 1 â…” hoc tempus adde tempori restitutionis maculae supputato si locus apparens Jovis excesserit medium subtrahe vero si defecerit à medio We have then the mean time of the return of the spot and to get the apparent time the equation of days according to the method of Monsieur Cassini of which a Table is inserted in the Ephemerides of Monsieur Flaminio de Mezzavachi must be made use of MICROSCOPIVM OR Some new Discoveries made with and concerning Microscopes A Letter of the Ingenious and Inquisitive Mr. Leeuwenhoeck of Delft sent to the Secretary of the Royal Society October 5. 1677. IN this Letter after the Relation of many curious Observations made with his Microscope he adds By some of my former Letters I have related what an innumerable company of little Animalcules I have discovered in waters of the truth of which affirmations that I might satisfie the Illustrious Philosophers of your Society I have here sent the Testimonials of eight credible persons some of which affirm they have seen 10000 others 30000 others 45000 little living Creatures in a quantity of water as big as a grain of Millet 92 of which go to the making up the bigness of a green Pea or the quantity of a natural drop of water in the desiring of which Testimonials I made it my request that they would only justifie that they might be within compass half the number that they believed each of them saw in the water and even so the number of those little creatures that would thereby be proved to be in one drop of water would be so great that it would exceed belief Now whereas by my Letter of the 9th of October 1676. I affirmed that there were more than 1000000 living Creatures contained in one drop of Pepper-water I should not have varied from the truth of it if I had asserted that there were 8000000 for if according to some of the included testimonials there might be found in a quantity of water as big as
Springs according to the modern Hypothesis though all here concurred did notwithstanding fail of producing that effect From the same it is also manifest that where Springs fail without want of the causes that Hypothesis supposeth necessary to produce them the occasion hath been from an apparent defect in the other that is the imperviousness of the earth through which the water must pass before a Spring can be produced both these appeared at Lipary where the general effect a Spring or fountain was wanting together with the causes of our Hypothesis though those of the other were manifestly existent and with all the advantages necessary It seeming to me a very rational conjecture that the greasie clammy Sulphur wherewith that earth was impregnated did by oppilating it hinder the insinuation of the Sea into it From the third observation you have the first deduction confirmed viz. That Springs are sometimes manifestly from the Sea That earth sweetens sea-Sea-water by Percolation And that the nearer Springs are to the Sea the more they retain of their pristine saltness and lose it by sensible degrees as they insinuate farther through it By the fourth the same is confirmed The fifth proveth that large streams flow without any possibility of being supplied by rain both for want of such rain and of dimensions to receive and contain it The sixth doth evidence that rain doth not penetrate the Surface of the earth even in a very dry parched Country and in the Torrid Zone and yet that Springs are under it which at once proves ours and refutes the other opinion the former appears by the water in those made Ponds lying there for a long time without any sensible loss thereof by its leaking into the earth The later by the Wells near the Sea and those found since under that impervious Land He that is not altogether a stranger to the weight pressure and Elasticity of the air the ascension of liquors through Filters and some other resembling Phaenomena would not account the like motion of the transcolated water to high hills to be an objection of any force against this Hypothesis but sure such solutions are no less beyond my ability than design Finding I have Paper enough left I will presume to trouble you with one rare appearance more that occurred to one Mr. Brasey of this Town and aged and very fat man who by taking Spirit of Vitriol in his mornings draughts to which he was advised as a remedy to asswage the exuberance of his belly found that it had no effect on his body but that a bundle of Keys which he used to carry always about him and that wonted to be very smooth and bright of a sudden became black and rusty though he never handled the Spirit nor carried it in his pocket so that we concurred in opinion that the sudorous Effluvia of his body impregnated with the Acid Spirit had occasioned it If so It 's very wonderful that so small a quantity thereof when diluted with so much juice as is contained in such a corpulent man should even insteam and the insensible Emanations make impressions on smooth Iron mauger the perpetual attrition by carrying them in his Pocket whereby such an effect one would think should be prevented or soon rubbed of I was going to make some reflections on this notable accident but I consider c. Plimmouth May 5. 1678. James Young THE Original of Springs is that which hath exercised the Pens of many learned Writers and very various have been the conjectures concernning it But amongst all I have met with I conceive none more probable than that which seems to fetch its original from the History of the Creation mentioned in Holy Writ that is that there is a Magazine of waters above as well as a Receptacle of waters upon or beneath the Surface of the Earth And that the Air is that Firmament which separates between the upper and lower waters and between these two is the circulation of waters or bloud of the Microcosm if I may so call it performed The water being sometimes by a particular constitution of the Air assisted by heat rarified and separated into minuter parts and so reduced into the form of Air and thereby being divided into Particles really smaller than those of the air in compassing and agitated with a greater degree of motion they take up more space and so become lighter than the Ambient and are thereby elevated and protruded upwards till they come to their place of poise or Equilibrium in the Air At other times by a differing constitution of the Air and deficiency of heat they lose their agitation and many of them again coalesce and so having less motion they condense and revert into water and so being heavier than the incompassing Air descend down again to the Earth in Mists Rain Snow Hail or the like That there is such a Circulation I think there is none doubts but still it remains a difficulty with those persons that grant this that all Rivers and Springs should have their original from the water that falls or condences out of the Air. To persuade such persons it may not possibly be unsuccessful to mention First That the great inundations or overflowing of Rivers manifestly proceed either from the Rain that immediately falls or from the melting of Snow or Ice that hath formerly fallen on the more eminent parts of Mountains to confirm which Histories enough might be brought were it necessary of Nilus Niger c. Secondly That it hath been observed and computed that communibus annis locis there falls water enough from the Sky in actual Rain Snow or Hail upon the Surface of England to supply all the water that runs back into the Sea by the Rivers and also all that may be supposed to evaporate nay though the quantity of the first be supposed twice as much as really it is This I have been assured by those that have both experimented and calculated it Thirdly That there is not yet certainly that I know or have heard of any other way of making salt water fresh but by Distillation which had there been such an Art it would in all probability have been made use of and so there is little probability that the Springs at the top of a high Hill should proceed from the Sea-water strained through the earth But were there such a filtration known I hinted in my Attempt published anno 1660 about Filtration how somewhat of that kind might be explained Fourthly That this Operation is constantly and most certainly performed by Nature both in exhaling and drawing up fresh steams and vapours from the Sea and all moyst bodies and in precipitating them down again in Rain Snow Hail but of the other we have no certainty Fifthly I have observed in several places where a Tree hath stood upon an high Hill singly and particularly at the brow of Box Hill near Darking in Surry that the body of the Tree is continually wet and at
thirteen Leagues distant along the Coast but more especially at or about a place called Fuencaliente being seven Leagues from the Town to the Southwards The trembling of the earth was observed to be more frequent and violent than elsewhere and so it continued till Wednesday the 17. ditto The People thereabouts were much affrighted for besides the Earthquake there was often heard a thundring noise as in the bowels of the earth on a Plain called the Canios which is before you come to the great descent towards the Sea where the hot Baths stand or the holy Fountain likewise at the ascent from the aforesaid Plain upwards at the great and wearisom Hill called Cuesta Cansada and until the Mountain of Goatyards and the same day in and about the said places mentioned the Earth began to open several mouths the greatest of them upon the said Goat Mountain being distant from the Sea a mile and an half and from the said opening came forth a very great heat and smell of Brimstone and the same day an hour before Sun-set at one of the mouths of the wearisom Hill was a trembling thereabout with more violence than any of the four days before and a great and black smoak came forth with a terrible thundring noise opening a very wide mouth and throwing out much fire with melted Rocks and stones and immediately after at another place eighty paces below hapned the like terrible noise and sight and in less than a quarter of an hour after there opened to the quantity of eighteen mouths towards the foot of the said Mountains and there issued out fire melted Rocks and other bituminous matter from all the said mouths and was presently formed into a great River of fire which took its course over the first mentioned Plain slowly going down towards the said holy Fountain but it pleased God being come within eight spaces of the Brink of the said great descent it turned a little on the right side and took its course with a very great fall towards the old Port which is that which was first entred by the Spaniards when they took the Islands Friday the nineteenth at two a clock in the afternoon in the aforesaid Mountain of Goats on the other side of Tassacorte there opened another mouth with much smoak and stones of fire and so closed again But the next day the twentieth it began again to smoak and continued with great trembling and noise in the bowels of the Earth until Sunday the twenty first at noon when with many flashings of fire and a greater thundring noise it finished that opening of that monstrous birth casting up into the Air both fire and stones and at night the smoak ceasing the thundring noise fire and stones increased forcing great fiery stones so high into the Air as we lost sight of them and with such violence sent them upwards that according to the best judgment they were five times longer in falling down which stones or Rocks were observed to be bigger than a Hogshead and what was most to be admired was that these breaking in the Air and changing into many several shapes distinctly appearing yet notwithstanding did reunite again in falling down Munday the twenty second it began again to cast forth black smoak for two hours time and after to thunder and throw up fire and stones with great violence Tuesday the twenty third at noon it smoaked again and from thence until night there was terrible thundring noise and casting up of fire and stones more fierce than before and about nine of the clock at night a very great trembling of the earth was felt and presently after followed three great stones of fire in the form of Globes which were forced about half a League in height and then like Granadoes broke in the Air with very great noise Wednesday the twenty fourth it was for an hours time very quiet and after it began with greater force than ever before by reason that some of the lower and first mouths were partly stopt with which the aforesaid River of fire ceased from running after it had dammed up the Bay of the old Port with burnt and melted Rocks and Stones and other matter wherewith the said River had run and had forced the Sea backward above a Musquet shot at random and near twice as much in breadth It ran into the Sea above sixty paces What fell into the Sea went congealing with a great smoak what came after forced and ran over that which went before so that the smoak was very great many paces within the Sea as far as seven fathoms depth which caused many men to imagine that some such like Vulcano had opened under the Sea in the said seven fathoms depth This night it cast up some stones like great fiery Globes as the former Thursday the twenty fifth it proved yet more violent than ever with thundring noise and flashes of fire Friday the twenty sixth the mouth that was at the foot of the Mountain began again to cast up as much fire and stones as ever and formed two other Rivers the one taking its course to Leeward of the first River leading toward the Rocks called de los Tacosos and the other took its way to windward of the first directly towards the Bathes or Holy Fountain and in this entrance the mouth of the Mountain was observed to be more quiet though it cast up much ashes like black small sand What dammage appears to have been done from its beginning to this day the twenty sixth of November being of thirteen days continuance hath been about nine or ten Country Houses burnt besides Out-houses and great Cisterns for water which are the poor Peoples only Remedy in those parts and upwards of three hundred Acres of ground are quite spoiled being covered with Rocks Stones and other Rubbish and Sand and if which God defend the said Vulcano do longer continue the damage must be far greater especially if any other mouth should break out higher as it is much feared by reason the earth in some places doth open with appearances as at first so that all about that circuit of the Fuencalliente will be lost and for what already hapned and yet continues with much terrour besides the fears of more in other parts thereabout the Inhabitants do leave their Habitations and like poor distressed people seek relief at the City and many leave the Island to seek their fortunes in the others From the twenty sixth of November that the aforesaid Relation was sent for Teneriff by the Chamber of this Island unto the General the said Vulcano continueth fierce and without ceasing rather more than less with a terrible thundring noise casting up Fire Stones Rocks and black Ashes and the three Rivers of Fire still running into the Sea and hath now dammed up all the Baths and holy Fountain to the great detriment of the Island that yearly received a great benefit thereby besides many damages dayly added to the former Several other mouths have since opened in the like dreadful manner near about the same place we see the great smoak by day and hear the thunder and noise like the shooting off of many Cannons and by night see also much of the fire very high in the Air from this City which is one and twenty miles from it We are now at the eleventh of December and fear we shall have more to write to you by the next Other Letters of the thirtieth of December mention that it then contined much at one as before and since others of the nineteenth of January say it is yet as dreadful as ever and little likelihood of ceasing from the thirteenth of November that it began to the nineteenth of January is about ten Weeks that it hath burnt and the last Letters mention abundance of Ashes or black Sand forced into the Air and carried all over the Island falling thick like Rain and frequently gathered in the City in the Streets Houses and Gardens though seven Leagues off FINIS ERRATA PAge 10. line 15. read the other viz. the vibrating l. 16. participates l. 17. 18. r. Vibration thereof but all Solids do exclude that menstruum or participate not of its motion p. 14 l. 11. for length r. number l. 12. r. occasions will be p. 15. l. 6. r. L M N O. l. 12. r. have of Elasticity is p. 18. l. 29. r. equal to ten p. 42. l. 12. r. from Oratava l. 12. r. or South-cast side p. 42. l. 9. for Prancis r. Francis
contrary If I could have seen any Comet to have covered any Star in its way it would have afforded a very circumstantial information especially if for this purpose it had been taken notice of with a good Telescope What the density of the innermost parts of this Earth we live on is none knows for though we find the parts on which we tread to be very compact and though by the industry of Miners it hath been proved so also to the depth of many hundred foot as Georgius Agricola relates and though it hath been found so even to a greater depth by the soundings of the bottom of the Sea yet none can bring an undeniable proof that the same is so solid to 25 miles deep much less that it is so to the center if therefore the external shell of this Globe were broken and removed 't is not impossible but that the middle parts thereof may be of the same nature with the middle parts of the Comets body and that those parts were the superficial parts or shell removed might like these of Comets expand themselves into the encompassing AEther Nay we find that notwithstanding the compactedness of the superficial parts of this Earth yet the AEther is able to take up into it self vast quantities of them and to keep them suspended some of them even to the height of many miles if any argument may be drawn from the height or length of the dawning or Crepusculum and this notwithstanding the attraction of the Earth in its perfect vigor or the gravitation of these parts thus taken up or their endeavour towards the center of the Earth How much more freely then might we imagine the encompassing AEther to prey upon and take up into it self the internal parts if they were of a loose and pervious texture and almost in a state of fluidity like a heap of Sand or a vessel of Alabaster-dust in boyling and were not so firmly united by the bonds of gravity and the vinculum of petrifaction as we find the superficial parts of the earth now are There is one argument to prove to us that there may be such a looseness of the internal parts of the earth and that is that the magnetical virtue varies which virtue without controyersie diffused through the whole body of the Earth and which hath a relation to the whole Globe and to every magnetical part thereof For by observation 't is found that the magnetical virtue acts upon a needle without it as the magnetical virtue of a round Loadstone doth on a Needle applied without that which as I may elsewhere shew hath a respect to the center of the stone differing from all the respects that Authors have hitherto ascribed to it even of Gilbert Kepler Kircher Descartes and our Country-man Mr. Bond who I think was the first man that endeavoured to reduce the variations observed by Wright Gellibrand Coster c. into a Theory and calculation Now this magnetical virtue which may be called one emanation of the Anima mundi as gravity may be called another being diffused through every part of it and seeming to be as it were Tota in toto tota in qualibet parte and to be more spiritual and to act more according to Magical and Mystical Laws than Light Sound or the like it giving to every magnetical body and every piece of it though infinitely divided the same proprieties it hath it self This magnetical virtue I say having such a relation and being forced thus to vary 't is very probable that the internal parts to which it hath a respect have a variation likewise and consequently that these internal parts which are supposed generally very dense compact and very closely and solidly united may be notwithstanding more loose and ununited and movable from certain causes To proceed therefore I say that it seems very probable to me that the body of Comets may be of the same nature and constitution with that of the internal parts of the Earth that these parts may by the help of the Aether be so agitated and blended together as to make them work upon and dissolve each other in the same manner as we have often had examples of some of the parts of the Earth a late instance of which was at Mongibel or Aetna in Sicily where the Fire continued for a long time and produced very considerable effects That this internal agitation may confound the gravitating principle and so leave the parts in a greater freedom to be dissolved by the encompassing Aether which is the agent that sets the other two at work to destroy each other that it may at length prey upon both and dissolve them both into it self and consequently not only the parts thus dissolved are elevated to a greater distance from the center of the Star or Nucleus or the superficies of it whose gravitating or attractive principle is much destroyed the Coma being in this Comet four or five Diameters of the Star or Nucleus but having given those parts leave thus far to ramble the gravitating principle of another body more potent acts upon it and makes those parts seem to recede from the center thereof though really they are but as it were left behind the body of the Star which is more powerfully attracted than the minuter steaming parts for I suppose the gravitating power of the Sun in the center of this part of the Heaven in which we are hath an attractive power upon all the bodies of the Planets and of the Earth that move about it and that each of those again have a respect answerable whereby they may be said to attract the Sun in the same manner as the Load-stone hath to Iron and the Iron hath to the Load-stone I conceive also that this attractive virtue may act likewise upon several other bodies that come within the center of its sphere of activity though 't is not improbable also but that as on some bodies it may have no effect at all no more than the Load-stone which acts on Iron hath upon a bar of Tin Lead Glass Wood c. so on other bodies it may have a clean contrary effect that is of protrusion thrusting off or driving away as we find one Pole of the Magnet doth the end of a Needle touched on the opposite part whence it is I conceive that the parts of the body of this Comet being confounded or jumbled as 't were together and so the gravitating principle destroyed become of other natures than they were before and so the body may cease to maintain its place in the Universe where first it was placed Whence instead of continuing to move round some central body whether Sun or Planet as it did whilst it maintained it self entire and so had its magnetical quality as I may so call it unconfounded it now leaves that circular way and by its motion which always tends to a straight line and would be so were it not bended into a curve by the attractive