supposed it and the Seas It came presently in my mind that by making a light Globe and setting it upon its Poles so tenderly ballanc't that it might but just have a Tendancy the same way I might inform my self by the help of a Loadstone which would admirably suppply the moons place by drawing by invisible lines what motion the stone carried in a circle round the Globe would give it and how it would agree with the motion I had suppos'd the earth to have but unexpected and succeeding troubles kept me at least three years otherways imploy'd but then I made a Globe about seven Inches in Diameter with three small Osier Hoops representing the Equator Horizantal and meridian lines through the Centre of this srom east to west I fixt an Axis of such Wyer as Mariners Needles are made of and upon the ends of the VVyer which did but just appear through the Hoops I Riveted two thin pieces of Iron each about an Inch long pointed I carried this Globe to a mathematical Instrument-maker that was master of a stone for I had none of my own and upon tryal found that holding the stone either in the east or west points or meridian-line it gave it no motion which I never doubted but if it varied never so little from those points either from east to west or the contrary it gave the Globe motion accordingly but for want of an Arch to keep the stone in all points at the same distance from the Globe I could not precisely observe at what point between the Horizontal and meridian lines it had its greatest motion which was the chief thing I made the tryal for But the Satisfaction I received by this made me resolve upon a second with a Globe more artificially made but unwelcom accidents have kept me from an opportunity to this day If any man shall think it worth his trouble I doubt not but that he may adjust such a Globe as I have been speaking of so as to represent this motion exactly enough Only let the Equator be made in all parts of an equal weight for that that I made was so heavy in the East and West points that when the stone came near the Meridian the Globe would decline with a motion somewhat too quick except I held the Stone very near and then it carried the Globe round with it It s not to be questioned but That this Motion of the Earth must make two Tides upon all Shores every 24 hours or in the space of time the Moon is moving round our Globe AS before let the Moon be in the Horizon East and this to be the first time of her going round our Globe the Earth and all Seas now without motion When the Moon takes her first steps above the Horizon she at the same time gives the earth Motion by turning it a little in the Centre from East to West this must cause an inequality in the surface of the water and that presently produces a motion so that now the Indian Atlantick and Paciffick Seas first began to move and at the same time take their course West the waters leaving the now higher western and failing upon the lower Eastern Shores and this Motion is continued till the Moon is South-East and then is it high-water and the first flood upon all Eastern low-water and the first Ebb upon all Western Shores Now this Tide was but three hours for it wanted three hours from a preceding motion but hereafter every Tide will be exactly six hours For now as the Moon from the South-east moves towards the Meridian the Earth returns to its level moving back again from West to East and now all Seas take their first journey East leaving the Eastern and falling upon the forsaken Western Shores and when the Moon has reacht the Meridian then will the Earth and Seas be at their first level but now the Motion seakes not for as the Moon in her never-ceasing motion leaves the Meridian and hastes away to the West so the motion of the Earth and Seas Eastward is continuedfor three hours longer that is till the Moon is South-west the Moon giving the Earth just as much motion now from East to West then this Tide was exactly six hours And now the Seas will take their course West again for as the Moon from the South-west declines towards the Horizon she lets fall the Western side of the Globe and then all Seas haste away to wash and fill the empty Eastern Shores And this motion is continued till the Moon is 45 degrees beneath the Horizon or North-west and then it will be high-water and the Second flood upon the Eastern and low-water and the second Ebb upon the Western Shores The next six hours the motion of the Earth and waters will be back again from West to East that is till the Moon is North-east and then will they have had two flood upon the Western and as many Ebbs upon the Eastern Shore And when about three hours after this the Moon shall be in the Horizon that is the same point of the Heavens she was in when the motion began then shall the Earth and Seas be at their Level the waters being just as high upon all shores now as then But though the waters now are neither higher nor lower upon the shores then when the motion began yet now it will be called half Flood upon the eastern and half Ebb upon the Western shores for that three hours before by a preceeding motion of the Earth the waters were so much higher upon the latter and so much lower upon the former then they were 24 hours before Then the three hours Flood and Ebb that was then wanting upon those shores is now made good So that in the space of 24 hours there has been two compleat Tides upon all Shores This is an order establisht by Nature plain and without Mystery it s but a gentle Rocking of the Earth in the Centre from East to West and west to east and though it may be hard to say precisely how much motion from east to west or the contrary the Moon gives the earth yet without troubling your head you may conclude it to be very little for let it be supposed that upon indifferent shores the water rises ten foot which yet is more then some will allow five foot of this is not to be acconuted for the first three hours of every Flood is but the return of the same water that by a contrary motion of the Earth first fell from those Shores For if the Earth was to keep its Level without motion the waters would be constantly as high upon all shores as they are when we say it is half flood or Ebb abating but so much as by the advantage of falling upon shores that have a smooth and easie assent or into Bays that open with wide mouths and after are contracted into narrow Corners or for some other manifest cause they are made to mount Now then
circle 'T is the same with the Sun and Moon about 14 days after this the Sun will be in the middle of Cancer and the Moon about the middle of Capricorn in Opposition with the Sun which is the same thing as if they were in the same circle and describe circles so much greater and by that advantage give the Earth a greater motion so that this spring tide must be a little higher then that that happened 14 days before And so every time the Moon shall be in Conjunction or Opposition with the Sun they will yet describe greater circles and by that means give the earth a greater Motion and accordingly the spring-tides will increase till the Sun has reacht the Equator And then being carried directly over the Body of the Earth in the greatest circle they must needs be thought to give the Earth and Seas the greatest motion So that now the spring-tides are at the very highest for now they will for the same reason decrease again till the Sun is in Capricorn and the next quarter increase c. And this without doubt is the only cause why the spring-tides are higher in March and September and lower in June and December I have endeavoured to inform my self how much the spring-tides are higher when the Sun is in the Equator then when in the Solstices and by the nearest Observation I could make here at London there is the difference of near two foot but I am not so well satisfied in it as I desire It will not be amiss to give you notice here that you shall hardly meet with two men that agree at what time the Spring Tides are at the highest I mean those Spring Tides that happen at New and Full-Moon some saying upon the day the Moon is in Conjunction or Opposition some the next day others will have it the third Tide after by which it should seem the time is not fixt I am in the mind that for one half of the year the Tides may increase a day or more after Full and Change but not the other half That is from June to September and from December till March my reason for it is this in these quarters the Sun is returning from the Tropicks to the Equators and then though the Sun a day after full and change do less assist the Moon in giving the Earth motion then upon the day yet it is so very little less that the disadvantage is more than recompenc'd by the Moons discribing the day after having a very swift motion a greater Circle about the Earth As the Sun goes from the Equator to the Tropick it is quite contrary for then the day after full and change the Moon describes a lesser Circle than the day before and then the Tides should not increase after New and Full-Moon at least not so long I have made some agreeable observations about this but have not had time for a strict inquiry though I have long thought of it Those that live near this or any other River that Ebbs and Flows may easily inform themselves whether this be so or no. But now besides these alterations of the Seas it must follow upon this motion of the Earth first that when the Tides rise highest they must fall lowest Secondly That the Tides in all Seas must set East and West and Thirdly That the motion of the Seas must begin at the same time all over the World The first of these you may at your pleasure observe and you shall alwayes find that the highest spring Tide makes the lowest Ebb. And all experimene'd men know the Tides set directly East and West upon all the utmost Eastern and Western Shores in the World And I think that Learned men are agreed that the motion begins at the same time in all Seas Thus much is certain that when the Moon is South-west or in the opposite Point of the Heavens that is North-east it is alwaies high-water upon all the utmost open western Shores of Europe and Affrica from Nova Zembla to the Cape of Good-hope And that when the Moon is South-east or North-west it is high-water upon the utmost Eastern Shores of America So that when it is high-water upon the first named it must be low-low-water upon the other Shores When they have the first of Ebb upon the Western Shores of Europe and Affrica they must have the first of Flood upon the opposite Eastern Shores of America By which it is plain that the motion begins at the same time in all these Seas and that what we call the Ebbing and Flowing of the Sea is nothing but the falling of the waters from off the Western upon the Eastern Shores and the same back again every 6 hours But further when it is high-high-water upon the Western Shores of Europe and Affrica it is high-high-water at the same time upon the Western Shores of Italy and upon the Shores of Syria at the bottom of the Mediteranean Sea and take good notice of it when it is high-high-water upon those Shores it is low-low-water at Venice and on the contrary Now this I take to be a very forceable argument to prove the motion of the Earth as I have supposed it and then the motion must begin at the same time in all Seas for it is unconceivable how this should otherwise happen but if you shall fancy the Terraqueous Globe to have a little motion from West to East you will then say that it must make high-high-water upon all the first named Shores and low-low-water at Venice But then let the Eastern side be turned up and it must make high-high-water at Venice and low-low-water upon all the other Shores The instances that may be taken out of this and other Seas to confirm this motion of the Earth are every where so many and so obvious that they cannot escape your notice if you will but take the least pains to inquire into these things Nor can you I think meet with any thing that shall seem to contradict it A reason now should be given Why upon some Shores they have almost no Tides when upon others they have great and almost incredible Floods I will onely name some of those places that are most remarkable for great Tides or the contrary without attempting to give a reason why it is so being almost confident that when you have observed those places well you will say that the Earth having such a motion it must of necessity be so I will begin in the North parts of Europe In some Bays upon the Shores of Nova Zembla it Flows 12. or 14 foot but in some places upon the Neighbouring Shores of Lapland they have no Tides at all and where they have most which is as I remember near the Bay of St. Nicholas one two or three foot Pet and Jackman searching for a passage by the North east to India found the waters in some of the Bays upon this Coast to be black and like a standing Pool without Motion Note that there are
Boat so high till you raise the water half an Inch above that mark and then in the like Space of time as you rais'd it let it return to its place and without letting the motion cease in three Minutes more depress that side as much below the Level as before you raised it that is till the water be fallen half an Inch below that Mark upon the Western shore and now in other six Minutes raise it to its first height and if you shall con tinue thus to move it you shall constantly give the Boat six minutes motion from East to west and from West to East and it will be said to Ebb and Flow upon that shore where you made the Mark a full Inch. And you shall have two Tides upon al shores every 24 Minutes and you may make those Tides to fall later by three quarters of a Minute every 24 minutes and to increase and decrease in what Periods of time you please Nay if a Hand a Sun on the contrary side of the Boat did sometimes hinder sometimes assist you the Motion of the Boat and Waters must be abated and increast accordingly or if you should remove your hand 23 degrees on either side of the Equator if I may so call it of the Boat you shall not in using but the same Strength give the Boat so great a Motion at the greatest Declination as in the middle the greatest Circle and if you have the Figure of those shores described in some of these Vessels where they have very great or almost no Tides you shall see the very same Alterations upon those shores And when you give the Boat the greatest Motion you must have the highest Spring Tides and the lowest Ebbs. The Waters must run directly East and West and the Motion must begin at the same time in all those little Seas And whatever other Accidents happens in the Flux or Reflux of the Sea you may plainly see even those Irregular motions as they are call'd observ'd in the Euripus its self as did I not think that upon such a motion of the Earth as I have supposed the Reason of those Alterations would manifestly appear I should have made some words about it And the motion of the Waters shall be in Proportion to the largeness of the Vessels only it shall be insensible in that narrow Vessel that stood North and South in the Boat Then it will not at all seem strange to you that the Alterations observ'd in other parts of the Ocean are not discernable in the Baltick Sea And I know that you think it would be the same thing if that Sea was plac't at either of the Poles or at the Equator And that if the Mediteranean Sea stood as the Baltick North and South that there would be very little or no Tides in that Sea But to be sure there could be none where now they have the greatest Tides that is upon the shores of Syria at Venice and at the Streights mouth And that if the Baltick Sea was plac't East and west the tides would be discernable enough in the Extremities of that Sea To conclude I lately met with a couple of Observations about the ebbing and flowing of the Sea in the Philosophical Transactions of the truly Royal Society not yet spoken of the first is That the water neither flows nor ebbs alike in Respect of equal Degrees but its Velocity increaseth with the tide till just mid-mid-water or half-flood at which time its Velocity is at the Strongest and then decreaseth proportionably till high-high-water or full Sea If you have understood what I have said you cannot but know that the first three hours of every flood and ebb is that three hours time in which the earth is returning to its Level then the business is to know whether it may be thought that the Moon le ts fall the side of the Globe with a Motion somwhat quicker then she raises it Or that the waters falling upon the empty shores must be thought to rise faster the first three hours then they can when the shores and Rivers are half full I must leave this to the Determination of wiser men The other Observation is indeed very notable which is that the morning tides for one half of the year are higher by a foot where it flows 18 or 20 foot then the evening tides and on the contrary the other half year It would trouble a good head to give a Satisfactory Reason how this should happen if the earth has not such a Motion as I have been speaking of but that being alow'd the cause of this odd effect is manifest enough Nay I am perswaded that the solving of this doubt would give much Reputation to the Hypothesis but because it would ingage me to speak of things that at this time I do not care for medling with I shall now let it alone but if the Learned shall think there is more in what I have already said then meer Conjecture as I am under a strong delusion if there be not then upon some other Occasion you may know more of my thoughts about this Till that be known farewel FINIS To be Sold by William Gadbury without the Bars in White-Chappel
THE Mutations of the Seas OR A Manifest Reason given for all the MUTATIONS Observed in the SEAS AND THIS By ways so Natural Plain and Easie that every man may understand the Manner and must conclude it to be so By JOHN BRYANTSON LONDON Printed by George Larkin in Scalding Alley in the Poultrey 1683. To the READER Reader IN the following paper you have the Solution of one of the greatest Secrets in Nature a manifest reason given for all the Mutations observed in the Seas and that by ways so natural plain and Easie that you and every man may understand the manner and must conlcude it to be so As first A reason is given why we have two Tides upon all shores in 24 hours Secondly Why those Tides fall exactly so many Minutes later every day as the Moon doth Thirdly By what meanes these Tides are made to Increase decrease every seven days why they are always highest when the Moon is in Conjunction or Opposition with the Sun and lowest when in a Quadrature or 90 Degrees distant Fourthly The true cause why the Spring-tides are higher in March and September then ordinary And Fiftly Why upon some shores the waters rise to a very great height when on Neighbouring shores they are hardly discernable with other Observations about the Flux and Reflux of the Seas And all these seemingly different motions of the Seas solv'd by one most easie simple and before for any thing I know unthought-of motion of the Earth But now I must tell you that I am a Seaman and then method and order will not be expected being rarely found amongst men of my Profession and I shall not scruple to confess that I have had some trouble to patch it up as it is finding by this little tryal that tho men unlearned may sometimes think of such things as these not unsuccessfully yet they shall not without a great deal of trouble and disadvantage be able to communicate their thoughts to others as you may too plainly see by this but I hope in a little time you may see what is here wanting made good by an able pen. In the mean time I have promised you much and with more then usual Confidence perswading my self that the hopes of being made acquainted with this great Secret will engage you to take a little pains more then ordinary to understand my meaning which if you once do you and I shall quickly be agreed you will then say â— that you know the true cause of the Ebbing and Flowing of the Sea If you think that I have made more words then needed about some things impute it to my fear that otherways I should not be understood or to my Ignorance not knowing the most expressive words the shortest way If in other things I am as much or more too short be so kind as to excuse me by thinking what your self would do in the same case and in this I am sure you will be of my mind that is that he that knows he does not speak well should say as little as he can And upon that account I have not troubled you nor concerned my self with any thing that I could any ways avoy'd Amongst many other defects you will find that my Ignorance in the Mathematicks as well as other parts of Learning has forc't me instead of Terms of Art which would have been much better understood to make use of such Words and Terms as being known to me I thought might best express my thoughts to others perhaps you will think that a very little time and pains in that Study might have enabled me to have set this off much more advantagiously I am of the same mind but the circumstances I stand in have not yet afforded me that time But I tell you again you shall find the thing it self to be true and then surely you will not be angry with me for these things For if a man should tel me that he would presently bring me to a place where lay un-own'd before Concealed Treasure if now the way he led me was none of the cleanest withal much about incumbred with Bryars and Thorns yet if at last he put me in possession of the promis'd and much desir'd Riches I would certainly by acknowledging the kindness prevent his making Excuses for not staying to inform himself better in the way before he undertook to be my guide The same upon the same Conditions is expected from you by John Bryantson The Mutations of the Seas OR A Manifest Reason given for all the Mutations observed in the Seas THE Arguments brought by Learned Men to prove that the Earth may have Motion has so far prevailed that it will not be look'd upon as an Extravagancy now to assert it So that I do not fear but that the Motion I suppose the Earth to have when well considered will willingly be admitted for if it may have any it may have this But because the Motion and Hypothesis upon which it is founded is altogether new it will I think be convenient to endeavour to lesson a little if I can the strangeness of it to prevent your throwing the Paper by as a rash and wide conjecture before you understand my meaning For I question not but that you will be supriz'd when you shall hear me say that the Moon and Sun give the Earth Motion as they are carried round our Globe but content your self and in two or three hours time if you have but patience to read so long and be not altogether a Stranger to the Heavenly Motions you will find the Motion I suppose the Earth to have to be so far from any thing you have yet heard or fancied to your self and such agreeableness between that and the Motions of the Seas that what but just before you thought strange if not fabulous you will then think not only easy but reasonable In the mean time you may consider that the Tides keep such equal pace so exactly observe the Motions of the Moon even to a minute of time that no wit or reason of man is able to exclude the Effects of that Planet It is most certain and very wise and Learned men in all Ages have been compelled to acknowledge it that the Moon by some secret vertue must give the Seas motion So that the matter may safely be brought to this short Issue one of these two things must of necessity follow Either the Moon must at the same time move the Seas all over the World and the Earth be yet immovable Or else give the Earth motion and by that means at the same time universally move the Seas Now if all those Learned men that have assign'd the Soveraignty of the Seas to the Moon upon the considera ion of the manifest agreement that is found to be between the Motions of the Ocean and that Luminary have thought it not impossible for the Moon to give the Seas Motion Why may it not be thought at least
as possible for the Moon to give the Earth motion and by consequence at the same time universally move the Seas As at the same time to move the Seas all over the world and let the Earth stand still And so much the rather since it is certainly true that Nature in all her opperations makes use of the most facil and simple means For take a Boat set the head and stern North and South place in this Boat 15 or 20 vessels of water now if you should bid one to move the water in all those vessels at the same time with a constant regular motion you would think him no wise man if he should attempt to do it any other wayes than by giving the Boat motion Nay he could not otherwayes do it without a great deal of help But if with one hand onely he shall lift up the side of the Boat a little and then depress that side as much below the level as before he rais'd it and shall for some time continue thus to move it from East to West and West to East he shall with as much ease and at least with as constant a motion at the same time move all the waters in all those vessels as he can by any other wayes move all the water in any one of them So it must be confest that the Moon by onely giving the Earth the containing vessel motion may at the same time and with as much ease move all the waters in the Indian Atlantick Paciâ—â—tick nd all other Seas as by any other ways or means that may or can be thought of move all the water in any one of those Seas Besides Nature commonly makes use of some inward Principle for opperations that are to be constant and regulat as the motions of the Seas are known to be but if it should be granted that the Moon might by some occult quallity some unknown Principle give the Seas motion and the Earth be yet immovable the difficulty would remain for no satisfactory reason has or can be given how by any influence or opperation the Moon may or can be supposed to have upon the waters 〈◊〉 should cause those different vicissitudes that are found in the Tide of the Seas Then if the appearance cannot be solv'd as in truth they cannot by any influence the Moon may or can have upon the Waters And that the same mutations must of necessity ensue upon the motion of the Earth and that it is as possible for the Moon to move the Earth and Seas together as to move the Seas alone and besides much the more facil and shorter way why should it appear so strange a Paradox to affirm that the Moon gives the Earth motion Nay who can doubt but that the Moon by some inward Principle gives the Earth motion And then you shall have this advantage into the bargain that you shall not be to seek for a Principle for the Magnetick vertue or force of attraction upon solid Bodies has been long known And you cannot deny the Earth to be a Magnetick Globe except you will deny that to be in the whole which more or less is manifestly to be seen in almost every part but most wonderfully in the Load-stone which is apart of the true Primary and integral substance of the Earth Now since there has alwayes been acknowledged to be a very great Affinity between the Moon and Earth and likeness of parts I think the Moon may reasonably enough be concluded to be so too And then these two great Magnates hanging in the thin Air must easily admit of motion so that I cannot see where the difficulty should be or what should hinder but that the Moon may give the Earth and the Earth the Moon if the Moon may be thought to have need of it motion If you shall think the distance too great consider that if a small Loadstone will give a Librated Needle a very swift motion at the distance of six or seven foot or more what distance may be thought great enough to give bounds to the Attractive Vertue of Load-stones so immensly great as the Terestrial Globe and Moon And besides it is not improbable but that the Moon may consist of such parts that the Appetite and Desire of Union may be much greater between the Earth and Moon then between the Loadstone and Iron Nay who can tell but that the more in ten parts of this our Globe may be indewed with a much more powerfull attractive vertue then any piece of stone yet found or perhaps that may be found upon or near the surface of the Earth I shall add that though perhaps the excellent use that is made of the Load-stone in Navigation may seem to some men sufficiently to answer the ends of its Creation yet it cannot be denyed but that the World was grown Old before the use of it was known so that Nature may be said to have indued the Magnet with those admirable Vertues from the beginning of the World till within a few years last past to no purpose for I think there was little use made of it before But now if you shall look upon the Terrestrial Globe and the rest of the superior Bodies to be nothing else as it is certain that the Earth is nothing else but great Magnates or Load-stones you cannot think but that wise Nature lodg'd these wonderfull vertues in them for far more wonderful uses and that it would be unreasonable to think that those vertues have not been kept in Exercise ever since the Creation And you shall not need to trouble your head to think how for you shall be forc't to acknowledge that by this Magnetick Vertue the Earth and Seas have alwayes been kept in motion Then if you consider the many Benefits that we enjoy which we could by no means want by the daily Tides you must confess it to be a very wonderful work of Providence and that as the same has been from the Beginning so it must continue so long as the Sun and Moon indure And then if those Bodies called Planets be Magnetick Globes or Worlds as surely that man never thought it worth his pains to consider whether or no they might not reasonably enough be esteemed so or else his Understanding must be yet in its leading strings that thinks otherwise and inhabited then such a Motion as I suppose the Earth to have will be necessary for them too which they may very well have for Mercury and Venus which are but the Sun's Moons may give the Sun and the Sun them motion And the like Friendly Offices may mutually pass between Jupiter and Saturn and the Stars or Moons that move about them And Neighbouring Stars may give Mars motion Onely there must be difference in the mutations that shall happen in their respective Seas in point of time as well because some of them have more Moon 's as that some of those Moon 's take more some less time in discribing their Circles then
what motion can you imagine the earth to have to be little enough to swell the waters five nay ten foot upon those shores where the Seas are two or 3000 miles or more over as they commonly are I am in the mind you will say and you may safely do it that this motion must be so little as to be almost altogether insensible So that though I have made a great many words about it and talkt of six hours motion from east to west and west to east yet when you have well considered the matter you may without any Prejudice to your Judgment very well suppose the Earth always to have had this motion though you knew it not As shall be abundantly confirmed to you by all that follows for The Moon giving the Earth this Motion the Tides must fall exactly so many Minutes later as the Moon doth THe other Motions of the Seas may as well be thought to depend upon the Motion of the Sun as Moon butin this the Moon seems to have all the sway and has so far outrivald the Sun that men in all ages have willingly assign'd the Empire of the Ocean to the Moon upon the account of the most exact agreement that is found between the Moon and Seas in this Motion of Retardation which is thus The Moon comes later to the same point of the Heavens one day with another by about forty eight minutes and the Tides observe the same When the Moon is in Conjunction with the Sun it is always high water at London-bridge at three a clock but now the same Tide will fall later every day as the Moon doth so that when the Moon is in Quadrature with the Sun the same Tide will fall six hours later that is at nine a Clock And so every seven days the same tide will fall later by six hours till the Moon is in Conjunction again and then the same Tide will fall out at three a clock as before If the Moon comes later to the same point of the Heaven 10 15 or 20 Minutes this day as it sometimes falls out so then the day before the Tides observe the same all the World over and that so precisely that no rule can be given to know the time of high-water but by knowing the true time of the Moons coming to the South And which is more if strong winds keep back or accellerate the Tides as oftentimes it happens half an hour or more yet the very next Tide if it be a calm shall observe the due time it should have done notwithstanding this interruption Then the question may well be askt whether or no the Seas Universally may be made thus exactly to keep time with the Motion of the Moon by any other ways or means whatever then by the motion of the Earth but no man can doubt but that if the Moon give the Earth motion after the manner that I have supposed it but that the Seas must observe the same even to a minute of time For if the Moon shall be South-east South-west North-west or North-east at which points the Motion of the earth and seas from East to West or West to East always begins this day at 12 a clock if to morrow the Moon comes later to these points 20 or 30 minutes its certain that the Motion of the Earth cannot begin till then and by consequence it must be high water so many minutes later This is so manifest that to say more would be needless And therefore I shall now let you know By what means the Motion of the Earth and Seas are abated and increased every seven days I Said before that the Moon and Sun by a powerful Magnetick attractive Vertue gave the Earth Motion I shall now add That by reason of the exceeding swift motion of the Moon the Sun sometimes comes to be so posited as directly to oppose the Moon in the Motion and sometimes to assist with all his forces But that you may the better understand what I say and at the same time fancy to your self how much the Sun contributes to or impedes the Motion as he comes to be every day diversly posited I will now examine how much the Sun may be concerned in the Action which may easily be gathered from this That when the Moon is 90 degrees from the Sun the Sun then directly opposes the Moon in the Motion and yet then the Tides here at London commonly rise about 12 foot At new and full Moon the Sun lends his utmost Assistance and then they rise about 16 foot now if when the Sun directly opposes the Moon the tides rise 12 foot and whenhe assists with all his forces they rise but 16. its certain that if the Sun did neither hinder nor assist the Moon alone would give the Earth so much motion as should constantly make the Tides rise here 14 foot So that the Suns interest can be but as two to 14. I do not pretend to be precise in this for perhaps there may be especially at some times of the year more then four foot difference between the Neap and spring Tides here and it may be the Neap and Spring Tides rise not commonly so high as I speak of but this is not so far from the Truth but that it may serve to make a pretty near Estimate Then now if you Understood after what manner I suppos'd the Earth was mov'd and at what points it had it's greatest Motion You will easily know how that motion comes to be abated or increast which is thus Suppose the Moon in the Horizon East and in Conjunction with the Sun this day then the Tides must be at the highest for now the Moon and Sun being carried round the Earth in the same Point they with their United forces must give it as great a motion as at any time they can For the next day it will be three quarters of an hour later before the Moon reaches the Horizon and then the Sun will be about 12 degrees above it So that this day when the Moon shall be South-east the place of greatest advantage of giving the Earth motion the Sun will be 12 degrees nearer the Meridian at which point the Sun cannot altogether so powerfully assist the Moon as the day before when they were both at the same time in the South-east Point So that this day the motion of the Earth is a very small matter abated And for the same reason the Motion every day abates till the Moon is in the quarter For about three days after change when the Moon shall be in the Horizon the Sun will be 45 degrees above it then this day all the time the Moon is moving from the Horizon to the South-east the Sun is moving from the South-east to the Meridian in all which points especially near the Meridian the Sun but faintly assists the Moon and in the meridian not at all But the next three days the Sun does not only less assist but every day more
Bays upon those Shores that have the same Forms that those have upon the other Shores where they have very great Tides Upon the Western Shores of Norway about 10 or 12 foot but upon the Southern Shores of Norway they hardly exceed one foot or two in the Baltick Sea no Tides In the Bay of Bristow 50 foot At the Town of Orange in Normandy they 〈◊〉 rise somemes 80 foot In the Bay of Biscay 18 20 or 24 foot Upon the Western shores of Affrica 10 12 or 14 foot But upon the Southern shores of Guiney and Benin they have very little Tides every ruffling Gale of Wind disorders them in many places there In Davis's streight in some places near the Entrance it flows about 30 foot At Port-Nelson which lies opposite to the mouth of the Streights where Sir Thomas Button Wintred 15 foot but in the South-part of the same Bay where as I take it Hadson Wintred but one foot observe this Bay well In the Bay of Foundy North-ward from New-England which place I had never heard spoken of for great Tides though I had been twice in North America but about two or three years since I saw a draught of the Sea Coasts thereabouts described in very large form where this Bay was represented in such a Figure that I concluded that if the Earth had such a motion as I before had supposed that then in this Bay there must be great Tides Not long after I met with a Master of a Ship that traded into those parts who upon my asking told me that it flow'd there 12 or 13 fathom but because I knew the man to be one that lov'd to make things that were strange seem wonderful I did not rely upon his Testimony but inquir'd of others who agreed that it flow'd there above 60 foot I now and alwayes mean spring-tides and in Bays or mouths of Rivers for where the Land is not indented the waters never rise so high In other Bays upon the Eastern shores of North America two or three fathom upon the Eastern shores of South America 10 or 12 foot according to the largness of the Seas which are there very unequal And because this may be a rule for other places you may observe that from Cape Frio which is in the south-east parts of Brasile to the Streights of Magallan the Land trenches away south-west Now when the first of flood falls upon the south-east shores of Brasile the waters rise considerably higher upon the shores as they do upon all other shores then the surface of the Sea at a very little distance is now the waters that next follow these not finding it easie to mount this height and yet being prest forwards by succeeding waters are part of them forc't to follow the trenching of the Land at a distance from the shore So that if in all this Tract of Land any Promontory or Head-land that juts it's self farther into the Sea then ordinary to catch or Arrest these waters in their passage happens to lie on the Western-side of any Bay or mouth of Rivers the Tide in those Bays or Rivers shall be proportionably higher but if the Land on the Eastern side be strecht farther out then the Tides in those Bays or Rivers will accordingly be abated It Ebbs and flows up the River of Plate says Mr. Purchas an 100 miles In the River Galegos near the entrance of the Streights and upon the shores of Fuego it flows 60 foot In the Bay that lies between the City of Martaban and Pegae in the Gulf of Bengalia in India the Tides set in with a great deal of fury and are said to rise there sometimes 40 foot In the Bay of Cambaja great Tides but they rise not so high nor is the motion so violent as in the former In the Red-Sea very little Tides What Tides they have upon the shores of New Guiney I cannot learn but without doubt very notable in that great Bay upon the western-shore The greatest Tides in the Mediteranean Sea are said to be upon the Coast of Syria where I think they rise seven or eight foot At the bottom of the Gulf of Venice 5 foot upon the Western shores of Italy not above a foot The Waters run through the streight of Sylla and Caribdis six hours East six hours west with a great deal of violence without rising or falling or but very little the like happens between all the Islands in this Sea only the course of the waters is not so rapid the passage not being so streight Now take a Globe set it upon its Poles the Horizon to cut the Equator at the points before spoken of and look upon any of these places or any other place that you know or that Report has made famous for great Tides or otherways and if the place be upon a Western shore as the Town of Orange in Normandy then imagine the Globe to have a little motion you had best fancy it to be exceeding little indeed and your self not near or else the very fear of being overwhelm'd with the falling Waters that must be crowded into this place will make you tremble from West to East but if the place be upon an Eastern shore as the Bay of Foundy then from East to West and the reason why these things are so will appear so manifestly that it must be delightful to consider it but it would add to the Pleasure if you had the Figures of those places you had a mind to Examine described in the largest Forms Take Notice that in all those places where I have said there is great Tides that the bottoms of those places are sandy and smooth which may indeed Contribute to the raising of the Waters there but cannot so properly be said to be the cause of the extraordinary Tides in those places As the great Tides are the cause of that for where ever the Tides sets with a direct Course into the mouths of Bays or Rivers they must have there alwayes sandy smooth Bottoms Except in large Bays or Rivers that have narrow Mouths and in them the quite contrary may happen for the greatest swelling of the Waters shall be near the Entrance and least of all in the Extremities of those Bays and they may have very uneven Bottoms c. In a word there is nothing of Mystery in these things Nothing but what is Consonant to the Laws Principles and Ordinary workings of Nature and most agreeable to Reason nothing but what you may imitate and at your pleasure see exactly represented what alterations happens upon the account of Rivers excepted by placing in a Boat as I said before 10 or more Vessels of Water of different sizes and Figures let one of those Vessels be long and very narrow and stand as the Boat North and South Now make a mark upon the Western side of any of those Vessels even with the Surface of the Water and then in three Minutes time lift up the Eastern-side of the