the Isles of Corsica and Sardinnia and in the Strands of Rome and Ligorne where it exceeds not half a foot we shall understand also why on the contrary where the risings and fallings are small the courses and recourses are great I say it is an easie thing to understand the causes of these accidents seeing that we meet with many manifest occurrences of the same nature in every kind of Vessel by us artificially composed in which the same effects are observed naturally to follow upon our moving it unevenly that is one while faster and another while flower Moreover considering in the fifth place that the same quantity of Water being moved though but gently in a spatious Channel comming afterwards to go through a narrow passage will of necessity run with great violence we shall not finde it hard to comprehend the cause of the great Currents that are made in the narrow Channel that separateth Calabria from Sicilia for that all the Waters that by the spaciousnesse of the Isle and by the Ionick Gulph happens to be pent in the Eastern part of the Sea though it do in that by reason of its largeness gently descend towards the West yet neverthelesse in that it is pent up in the Bosphorus it floweth with great violence between Scilla and Caribdis and maketh a great agitation Like to which and much greater is said to be betwixt Africa and the great Isle of St. Lorenzo where the Waters of the two vast Seas Indian and Ethiopick that lie round it must needs be straightned into a lesse Channel between the said Isle and the Ethiopian Coast. And the Currents must needs be very great in the Straights of Megallanes which joyne together the vast Oceans of Ethiopia and Del Zur called also the Pacifick Sea It follows now in the sixth place that to render a reason of some more abstruse and incredible accidents which are observed upon this occasion we make a considerable reflection upon the two principal causes of ebbings and flowings afterwards compounding and mixing them together The first and simplest of which is as hath often been said the determinate acceleration and retardation of the parts of the Earth from whence the Waters have a determinate period put to their decursions towards the East and return towards the West in the time of twenty four hours The other is that which dependeth on the proper gravity of the Water which being once commoved by the primary cause seeketh in the next place to reduce it self to Aequilibrium with iterated reciprocations which are not determined by one sole and prefixed time but have as many varieties of times as are the different lengths and profundities of the receptacles and Straights of Seas and by what dependeth on this second principle they would ebbe and flow some in one hour others in two in four in six in eight in ten c. Now if we begin to put together the first cause which hath its set Period from twelve hours to twelve hours with some one of the secondary that hath its Period verb. grat from five hours to five hours it would come to passe that at sometimes the primary cause and secondary would accord to make impulses both one the same way and in this concurrency and as one may call it unanimous conspiration the flowings shall be great At other times it happening that the primary impulse doth in a certain manner oppose that which the secondary Period would make and in this contest one of the Principles being taken away that which the other would give will weaken the commotion of the Waters and the Sea will return to a very tranquil State and almost immoveable And at other times according as the two aforesaid Principles shall neither altogether contest nor altogether concur there shall be other kinds of alterations made in the increase and diminution of the ebbing and flowing It may likewise fall out that two Seas considerably great and which communicate by some narrow Channel may chance to have by reason of the mixtion of the two Principles of motion one cause to flow at the time that the other hath cause to move a contrary way in which case in the Channel whereby they disimbogue themselves into each other there do extraordinary conturbations insue with opposite and vortick motions and most dangerous boilings and breakings as frequent relations and experiences do assure us From such like discordant motions dependent not onely on the different positions and longitudes but very much also upon the different profundities of the Seas which have the said intercourse there do happen at sometimes different commotions in the Waters irregular and that can be reduced to no rules of observation the reasons of which have much troubled and alwayes do trouble Mariners for that they meet with them without seeing either impulse of winds or other eminent aereal alteration that might occasion the same of which disturbance of the Air we ought to make great account in other accidents and to take it for a third and accidental cause able to alter very much the observation of the effects depending on the secondary and more essential causes And it is not to be doubted but that impetuous windes continuing to blow for example from the East they shall retein the Waters and prohibit the reflux or ebbing whereupon the second and third reply of the flux or tide overtaking the former at the hours prefixed they will swell very high and being thus born up for some dayes by the strength of the Winds they shall rise more than usual making extraordinary inundations We ought also and this shall serve for a seventh Probleme to take notice of another cause of motion dependant on the great abundance of the Waters of great Rivers that discharge themselves into Seas of no great capacity whereupon in the Straits or Bosphori that communicate with those Seas the Waters are seen to run always one way as it happeneth in the Thracian Bosphorus below Constantinople where the water alwayes runneth from the Black-Sea towards the Propontis For in the said Black-Sea by reason of its shortnesse the principal causes of ebbing and flowing are but of small force But on the contrary very great Rivers falling into the same those huge defluxions of water being to passe and disgorge themselves by the the straight the course is there very notable and alwayes towards the South Where moreover we ought to take notice that the said Straight or Channel albeit very narrow is not subject to perturbations as the Straight of Scilla and Carybdis for that that hath the Black-Sea above towards the North and the Propontis the Aegean and the Mediterranean Seas joyned unto it though by a long tract towards the South but now as we have observed the Seas though of never so great length lying North and South are not much subject to ebbings and flowings but because the Sicilian Straight is situate between the parts of the Mediterrane distended
straight it shall agree to any simple natural body or if not so then the supposion of Aristotle is defective It appears moreover that Aristotle hinteth but one circular motion alone to be in the World and consequently but one onely Center to which alone the motions of upwards and downwards refer All which are apparent proofs that Aristotles aim is to make white black and to accommodate Architecture to the building and not to modle the building according to the precepts of Arthitecture for if I should say that Nature in Universal may have a thousand Circular Motions and by consequence a thousand Centers there would be also a thousand motions upwards and downwards Again he makes as hath been said a simple motion and a mixt motion calling simple the circular and right and mixt the compound of them two of natural bodies he calls some simple namely those that have a natural principle to simple motion and others compound and simple motions he attributes to simple bodies and the compounded to the compound but by compound motion he doth no longer understand the mixt of right and circular which may be in the World but introduceth a mixt motion as impossible as it is impossible to mixe opposite motions made in the same right line so as to produce from them a motion partly upwards partly downwards and to moderate such an absurdity and impossibility he asserts that such mixt bodies move according to the simple part predominant which necessitates others to say that even the motion made by the same right line is sometimes simple and sometimes also compound so that the simplicity of the motion is no longer dependent onely on the simplicity of the line SIMPL. How Is it not difference sufficient that the simple and absolute are more swift than that which proceeds from predominion and how much faster doth a piece of pure Earth descend than a piece of Wood SAGR. Well Simplicius But put case the simplicity for this cause was changed besides that there would be a hundred thousand mixt motions you would not be able to determine the simple nay farther if the greater or lesse velocity be able to alter the simplicity of the motion no simple body should move with a simple motion since that in all natural right motions the velocity is ever encreasing and by consequence still changing the simplicity which as it is simplicity ought of consequence to be immutable and that which more importeth you charge Aristotle with another thing that in the definition of motions compounded he hath not made mention of tardity nor velocity which you now insert for a necessary and essential point Again you can draw no advantage from this rule for that there will be amongst the mixt bodies some and that not a few that will move swiftly and others more slowly than the simple as for example Lead and Wood in comparison of earth and therefore amongst these motions which call you the simple and which the mixt SIMPL. I would call that simple motion which is made by a simple body and mixt that of a compound body SAGR. Very well and yet Simplicius a little before you said that the simple and compound motions discovered which were mixt and which were simple bodies now you will have me by simple and mixt bodies come to know which is the simple and which is the compound motion an excellent way to keep us ignorant both of motions and bodies Moreover you have also a little above declared how that a greater velocity did not suffice but you seek a third condition for the definement of simple motion for which Aristotle contented himself with one alone namely of the simplicity of the Space or Medium But now according to you the simple motion shall be that which is made upon a simple line with a certain determinate velocity by a body simply moveable Now be it as you please and let us return to Aristotle who defineth the mixt motion to be that compounded of the right and circular but produceth not any body which naturally moveth with such a motion SALV I come again to Aristotle who having very well and Methodically begun his discourse but having a greater aim to rest at and hit a marke predesigned in his minde then that to which his method lead him digressing from the purpose he comes to assert as a thing known and manifest that as to the motions directly upwards or downwards they naturally agree to Fire and Earth and that therefore it is necessary that besides these bodies which are neer unto us there must be in nature another to which the circular motion may agree which shall be so much the more excellent by how much the circular motion is more perfect then the streight but how much more pefect that is than this he determines from the greatness of the circular lines perfection above the right line calling that perfect and this imperfect imperfect because if infinite it wanteth a termination and end and if it be finite there is yet something beyond which it may be prolonged This is the basis ground work and master-stone of all the Fabrick of the Aristotelian World upon which they superstruct all their other properties of neither heavy nor light of ingenerable incorruptible exemption from all motions some onely the local c. And all these passions he affirmeth to be proper to a simple body that is moved circularly and the contrary qualities of gravity levity corruptibility c. he assigns to bodies naturally moveable in a streight line for that if we have already discovered defects in the foundation we may rationally question what soever may farther built thereon I deny not that this which Aristotle hitherto hath introduced with a general discourse dependent upon universal primary principles hath been since in process of time re-inforced with particular reasons and experiments all which it would be necessary distinctly to consider and weigh but because what hath been said hitherto presents to such as consider the same many and no small difficulties and yet it would be necessary that the primary principles and fundamentals were certain firm and established that so they might with more confidence be built upon it would not be amiss before we farther multiply doubts to see if haply as I conjecture betaking our selves to other waies we may not light upon a more direct and secure method and with better considered principles of Architecture lay our primary fundamentals Therefore suspending for the present the method of Aristotle which we will re-assume again in its proper place and particularly examine I say that in the things hitherto affirmed by him I agree with him and admit that the World is a body enjoying all dimensions and therefore most perfect and I add that as such it is necessarily most ordinate that is having parts between themselves with exquisite and most perfect order disposed which assumption I think is not to be denied neither by you or any
though indeed they have an influence upon the Elements It is requisite if you will prove generation and corruption in Coelestial bodies that you shew that there resides contrarieties between them SAGR. See how I will find those contrarieties between them The first fountain from whence you derive the contrariety of the Elements is the contrariety of their motions upwards and downwards it therefore is necessary that those Principles be in like manner contraries to each other upon which those motions depend and because that is moveable upwards by lightness and this downwards by gravity it is necessary that lightness and gravity are contrary to each other no less are we to believe those other Principles to be contraries which are the causes that this is heavy and that light but by your own confession levity and gravity follow as consequents of rarity and density therefore rarity and density shall be contraries the which conditions or affections are so amply found in Coelestial bodies that you esteem the stars to be onely more dense parts of their Heaven and if this be so it followeth that the density of the stars exceeds that of the rest of Heaven by almost infinite degrees which is manifest in that Heaven is infinitely transparent and the stars extremely opacous and for that there are there above no other qualities but more and less density and rarity which may be causes of the greater or less transparency There being then such contrariety between the Coelestial bodies it is necessary that they also be generable and corruptible in the same manner as the Elementary bodies are or else that contrariety is not the cause of corruptibility c. SIMPL. There is no necessity either of one or the other for that density and rarity in Coelestial bodies are not contraries to each other as in Elementary bodies for that they depend not on the primary qualities cold and heat which are contraries but on the more or less matter in proportion to quantity now much and little speak onely a relative opposition that is the least of oppositions and which hath nothing to do with generation and corruption SAGR. Therefore affirming that density and rarity which amongst the Elements should be the cause of gravity and levity which may be the causes of contrary motions sursum and deorsâ—â—m on which again dependeth the contrarieties for generation and corruption it sufficeth not that they be those densnesses and rarenesses which under the same quantity or if you will mass contain much or little matter but it is necessary that they be densnesses and rarenesses caused by the primary qualities hot and cold otherwise they would operate nothing at all but if this be so Aristotle hath deceived us for that he should have told it us at first and so have left written that those simple bodies are generable and corruptible that are moveable with simple motions upwards and downwards dependent on levity and gravity caused by rarity and density made by much or little matter by reason of heat and cold and not to have staid at the simple motion sursum and deorsùm for I assure you that to the making of bodies heavy or light whereby they come to be moved with contrary motions any kind of density and rarity sufficeth whether it proceed from heat and cold or what else you please for heat and cold have nothing to do in this affair and you shall upon experiment find that a red iron which you must grant to have heat weigheth as much and moves in the same manner as when it is cold But to overpass this also how know you but that Coelestial rarity and density depend on heat and cold SIMPL. I know it because those qualities are not amongst Coelestial bodies which are neither hot nor cold SALV I see we are again going about to engulph our selves in a bottomless ocean where there is no getting to shore for this is a Navigation without Compass Stars or Rudder so that it will follow either that we be forced to pass from Shelf to Shelf or run on ground or to sail continually in danger of being lost Therefore if according to your advice we shall proceed in our main design we must of necessity for the present overpass this general consideration whether direct motion be necessary in Nature and agree with some bodies and come to the particular demonstrations observations and experiments propounding in the first place all those that have been hitherto alledged by Aristotle Ptolomey and others to prove the stability of the Earth endeavouring in the next place to answer them and producing in the last place those by which others may be perswaded that the Earth is no less than the Moon or any other Planet to be numbered amongst natural bodies that move circularly SAGR. I shall the more willingly incline to this in that I am better satisfied with your Architectonical and general discourse than with that of Aristotle for yours convinceth me without the least scruple and the other at every step crosseth my way with some block And I see no reason why Simplicius should not be presently satisfied with the Argument you alledg to prove that there can be no such thing in nature as a motion by a right line if we do but presuppose that the parts of the Universe are disposed in an excellent constitution and perfect order SALV Stay a little good Sagredus for just now a way comes into my mind how I may give Simplicius satisfaction provided that he will not be so strictly wedded to every expression of Aristotle as to hold it heresie to recede in any thing from him Nor is there any question to be made but that if we grant the excellent disposition and perfect order of the parts of the Universe as to local scituation that then there is no other but the circular motion and rest for as to the motion by a right line I see not how it can be of use for any thing but to reduce to their natural constitution some integral bodies that by some accident were remov'd and separated from their whole as we said above Let us now consider the whole Terrestrial Globe and enquire the best we can whether it and the other Mundane bodies are to conserve themselves in their perfect and natural disposition It is necessary to say 〈◊〉 that it rests and keeps perpetually immoveable in its place or else that continuing always in its place it revolves in its self or that it turneth about a Centre moving by the circumference of a circle Of which accidents both Aristotle and Ptolomey and all their followers say that it hath ever observed and shall continually keep the first that is a perpetual rest in the same place Now why I pray you ought they not to have said that its natural affection is to rest immoveable rather than to make natural unto it the motion downwards with which motion it never did or shall
sit ratio totius partium those Countreys being a part of the Earth as well as ours they must of necessity be alterable as these are SALV And why have you not without being put to believe other mens relations examined and observed those alterations with your own eyes SIMPL. Because those places besides that they are not exposed to our eyes are so remote that our sight cannot reach to comprehend therein such like mutations SALV See now how you have unawares discovered the fallacy of your Argument for if you say that the alterations that are seen on the Earth neer at hand cannot by reason of the too great distance be seen in America much lesse can you see them in the Moon which is so many hundred times more remote And if you believe the alterations in Mexico upon the report of those that come from thence what intelligence have you from the Moon to assure you that there is no such alterations in it Therefore from your not seeing any alterations in Heaven whereas if there were any such you could not see them by reason of their too great distance and from your not having intelligence thereof in regard that it cannot be had you ought not to argue that there are no such alterations howbeit from the seeing and observing of them on Earth you well argue that therein such there are SIMPL. I will shew so great mutations that have befaln on the Earth that if any such had happened in the Moon they might very well have been observed here below We find in very antient records that heretofore at the Streights of Gibraltar the two great Mountains Abila and Calpen were continued together by certain other lesse Mountains which there gave check to the Ocean but those Hills being by some cause or other separated and a way being opened for the Sea to break in it made such an inundation that it gave occasion to the calling of it since the Mid-land Sea the greatness whereof considered and the divers aspects the surfaces of the Water and Earth then made had it been beheld afar off there is no doubt but so great a change might have been discerned by one that was then in the Moon as also to us inhabitants of the Earth the like alterations would be perceived in the Moon but we find not in antiquity that ever there was such a thing seen therefore we have no cause to say that any of the Coelestial bodies are alterable c. SALV That so great alterations have hapned in the Moon I dare not say but for all that I am not yet certain but that such changes might occur and because such a mutation could onely represent unto us some kind of variation between the more clear and more obscure parts of the Moon I know not whether we have had on Earth observant Selenographers who have for any considerable number of years instructed us with so exact Selenography as that we should confidently conclude that there hath no such change hapned in the face of the Moon of the figuration of which I find no more particular description than the saying of some that it represents an humane face of others that it is like the muzle of a Lyon and of others that it is Cain with a bundle of thorns on his back therefore to say Heaven is unalterable because that in the Moon or other Coelestial bodies no such alterations are seen as discover themselves on Earth is a bad illation and concludeth nothing SAGR. And there is another odd kind of scruple in this Argument of Simplicius running in my mind which I would gladly have answered therefore I demand of him whether the Earth before the Mediterranian inundation was generable and corruptible or else began then so to be SIMPL. It was doubtless generable and corruptible also before that time but that was so vast a mutation that it might have been observed as far as the Moon SAGR. Go to if the Earth was generable and corruptible before that Inundation why may not the Moon be so likewise without such a change Or why should that be necessary in the Moon which importeth nothing on Earth SALV It is a shrewd question But I am doubtfull that Simplicius a little altereth the Text of Aristotle and the other Peripateticks who say they hold the Heavens unalterable for that they see therein no one star generate or corrupt which is probably a less part of Heaven than a City is of the Earth and yet innumerable of these have been destroyed so as that no mark of them hath remain'd SAGR. I verily believed otherwise and conceited that Simplicius dissembled this exposition of the Text that he might not charge his Master and Consectators with a notion more absurd than the former And what a folly it is to say the Coelestial part is unalterable because no stars do generate or corrupt therein What then hath any one seen a Terrestrial Globe corrupt and another regenerate in its place And yet is it not on all hands granted by Philosophers that there are very few stars in Heaven less than the Earth but very many that are much bigger So that for a star in Heaven to corrupt would be no less than if the whole Terrestrial Globe should be destroy'd Therefore if for the true proof of generation and corruption in the Universe it be necessary that so vast bodies as a star must corrupt and regenerate you may satisfie your self and cease your opinion for I assure you that you shall never see the Terrestrial Globe or any other integral body of the World to corrupt or decay so that having been beheld by us for so many years past they should so dissolve as not to leave any footsteps of them SALV But to give Simplicius yet fuller satisfaction and to reclaim him if possible from his error I affirm that we have in our age new accidents and observations and such that I question not in the least but if Aristotle were now alive they would make him change his opinion which may be easily collected from the very manner of his discoursing For when he writeth that he esteemeth the Heavens inalterable c. because no new thing was seen to be begot therein or any old to be dissolved he seems implicitely to hint unto us that when he should see any such accident he would hold the contrary and 〈◊〉 as indeed it is meet sensible experiments to natural reason for had he not made any reckoning of the senses he would not then from the not seeing of any sensible mutation have argued immutability SIMPL. Aristotle deduceth his principal Argument à priori shewing the necessity of the inalterability of Heaven by natural manifest and clear principles and then stablisheth the same à posteriori by sense and the traditions of the antients SALV This you speak of is the Method he hath observed in delivering his Doctrine but I do not bethink it yet to be that wherewith he
whereupon the reflex rayes issue unitedly towards one and the same place but the rest of the pavement which is dry hath its protuberances that is an innumerable variety of inclinations in its smallest particles whereupon the reflections of the light scatter towards all parts but more weakly than if they had gone all united together and therefore the same sheweth almost all alike beheld several wayes but far lesse clear than the moistned brick I conclude therefore that the surface of the Sea beheld from the Moon in like manner as it would appear most equal the Islands and Rocks deducted so it would shew lesse clear than that of the Earth which is montanous and uneven And but that I would not seem as the saying is to harp too much on one string I could tell you that I have observed in the Moon that secondary light which I told you came to her from the reflection of the Terrestrial Globe to be notably more clear two or three dayes before the conjunction than after that is when we see it before break of day in the East than when it is seen at night after Sun-set in the West of which difference the cause is that the Terrestrial Hemisphere which looks towards the Eastern Moon hath little Sea and much Land to wit all Asia whereas when it is in the West it beholds very great Seas that is the whole Atlantick Ocean as far as America An Argument sufficiently probable that the surface of the water appears lesse splendid than that of the Earth SIMPL. So that perhaps you believe those great spots discovered in the face of the Moon to be Seas and the other clearer parts to be Land or some such thing SALV This which you ask me is the beginning of those incongruities which I esteem to be between the Moon and the Earth out of which it is time to dis-ingage our selves for we have stayed too long in the Moon I say therefore that if there were in nature but one way onely to make two superficies illustrated by the Sun to appear one more clear than the other and that this were by the being of the one Earth and the other Water it would be necessary to say that the surface of the Moon were part earthy and part aquatick but because we know many wayes to produce the same effect and others there may be which we know not of therefore I dare not affirm the Moon to consist of one thing more than another It hath been seen already that a silver plate boiled being toucht with the Burnisher becometh of white obscure that the moist part of the Earth shews more obscure than the dry that in the tops of Hills the woody parts appear more gloomy than the naked and barren which hapneth because there falleth very much shadow among the Trees but the open places are illuminated all over by the Sun And this mixtion of shadow hath such operation that in tufted velvet the silk which is cut is of a far darker colour than that which is not cut by means of the shadows diffused betwixt thred and thred and a plain velvet shews much blacker than a Taffata made of the same silk So that if there were in the Moon things which should look like great Woods their aspect might represent unto us the spots which we discover alike difference would be occasioned if there were Seas in her and lastly nothing hindreth but that those spots may really be of an obscurer colour than the rest for thus the snow makes the mountains shew brighter That which is plainly observed in the Moon is that its most obscure parts are all plains with few rises and bancks in them though some there be the rest which is of a brighter colour is all full of rocks mountains hillocks of spherical and other figures and in particular round about the spots are very great ledges of mountains That the spots be plain superficies we have assured proof in that we see how that the term which distinguisheth the part illuminated from the obscure in crossing the spots makes the intersection even but in the clear parts it shews all craggy and shagged But I know not as yet whether this evennesse of superficies may be sufficient of it self alone to make the obscurity appear and I rather think not Besides I account the Moon exceeding different from the Earth for although I imagine to my self that those are not idle and dead Regions yet I affirm not that there are in them motion and life much less that there are bred plants animals or other things like to ours but if such there be they should nevertheless be very different and remote from our imagination And I am induced so to think because in the first place I esteem that the matter of the Lunar Globe consists not of Earth and Water and this alone sufficeth to take away the generations and alterations resembling ours but now supposing that there were in the Moon Water and Earth yet would they not produce plants and animals like to ours and this for two principal reasons The first is that unto our productions there are required so many variable aspects of the Sun that without them they would all miscarry now the habitudes of the Sun towards the Earth are far different from those towards the Moon We as to the diurnal illumination have in the greater part of the Earth every twenty four hours part day and part night which effect in the Moon is monethly and that annual declination and elevation of the Sun in the Zodiack by which it produceth diversity of Seasons and inequality of dayes and nights are finished in the Moon in a moneth and whereas the Sun to us riseth and declineth so much that from the greatest to the least altitude there is a difference of almost 47 degrees for so much is the distance from one to the other Tropick this is in the Moon but ten degrees only or little more namely as much as the greatest Latitudes of the Dragon on each side the Ecliptick Now consider what effect the Sun would have in the torrid Zone should it continually for fifteen dayes together beam forth its Rayes upon it which without all question would destroy plants herbs and living creatures and if it should chance that there were any production it would be of herbs plants and creatures very different from those which are now there Secondly I verily believe that in the Moon there are no rains for if Clouds should gather in any part thereof as they do about the Earth they would thereupon hide from our sight some of those things which we with the Telescope behold in the Moon and in a word would some way or other change its Phaenomenon an effect which I could never by long and diligent observations discover but alwayes beheld it in a even and pure serenity SAGR. To this may be answered either that there might be great
against themselves observations experiences and reasons of farre greater force than those alledged by Aristotle Ptolomy and other opposers of the same conclusions and by this means you shall come to ascertain your self that they were not induced through want of knowledge or expetience to follow that opinion SAGR. It is requisite that upon this occasion I relate unto you some accidents that befell me so soon as I first began to hear speak of this new doctrine Being very young and having scarcely finished my course of Philosophy which I left off as being set upon other employments there chanced to come into these parts a certain Foreigner of Rostock whose name as I remember was Christianus Vurstitius a follower of Copernicus who in an Academy made two or three Lectures upon this point to whom many flock't as Auditors but I thinking they went more for the novelty of the subject than otherwise did not go to hear him for I had concluded with my self that that opinion could be no other than a solemn madnesse And questioning some of those who had been there I perceived they all made a jest thereof execpt one who told me that the businesse was not altogether to be laugh't at and because this man was reputed by me to be very intelligent and wary I repented that I was not there and began from that time forward as oft as I met with any one of the Copernican perswasion to demand of them if they had been alwayes of the same judgment and of as many as I examined I found not so much as one who told me not that he had been a long time of the contrary opinion but to have changed it for this as convinced by the strength of the reasons proving the same and afterwards questioning them one by one to see whether they were well possest of the reasons of the other side I found them all to be very ready and perfect in them so that I could not truly say that they had took up this opinion out of ignorance vanity or to shew the acutenesse of their wits On the contrary of as many of the Peripateticks and Ptolomeans as I have asked and out of curiosity I have talked with many what pains they had taken in the Book of Copernicus I found very few that had so much as superficially perused it but of those whom I thought had understood the same not one and moreover I have enquired amongst the followers of the Peripatetick Doctrine if ever any of them had held the contrary opinion and likewise found none that had Whereupon considering that there was no man who followed the opinion of Copernicus that had not been first on the contrary side and that was not very well acquainted with the reasons of Aristotle and Ptolomy and on the contrary that there is not one of the followers of Ptolomy that had ever been of the judgment of Copernicus and had left that to imbrace this of Aristotle considering I say these things I began to think that one who leaveth an opinion imbued with his milk and followed by very many to take up another owned by very few and denied by all the Schools and that really seems a very great Paradox must needs have been moved not to say forced by more powerful reasons For this cause I am become very curious to dive as they say into the bottom of this businesse and account it my great good fortune that I have met you two from whom I may without any trouble hear all that hath been and haply can be said on this argument assuring my self that the strength of your reasons will resolve all scruples and bring me to a certainty in this subject SIMPL. But it s possible your opinion and hopes may be disappointed and that you may find your selves more at a losse in the end than you was at first SAGR. I am very confident that this can in no wise befal me SIMPL. And why not I have a manifest example in my self that the farther I go the more I am confounded SAGR. This is a sign that those reasons that hitherto seemed concluding unto you and assured you in the truth of your opinion begin to change countenance in your mind and to let you by degrees if not imbrace at least look towards the contrary tenent but I that have been hitherto indifferent do greatly hope to acquire rest and satisfaction by our future discourses and you will not deny but I may if you please but to hear what perswadeth me to this expectation SIMPL. I will gladly hearken to the same and should be no lesse glad that the like effect might be wrought in me SAGR. Favour me therefore with answering to what I shall ask you And first tell me Simplicius is not the conclusion which we seek the truth of Whether we ought to hold with Aristotle and Ptolomy that the Earth onely abiding without motion in the Centre of the Universe the Coelestial bodies all move or else Whether the Starry Sphere and the Sun standing still in the Centre the Earth is without the same and owner of all those motions that in our seeming belong to the Sun and fixed Stars SIMPL. These are the conclusions which are in dispute SAGR. And these two conclusions are they not of such a nature that one of them must necessarily be true and the other false SIMPL. They are so We are in a Dilemma one part of which must of necessity be true and the other untrue for between Motion and Rest which are contradictories there cannot be instanced a third so as that one cannot say the Earth moves not nor stands still the Sun and Stars do not move and yet stand not still SAGR. The Earth the Sun and Stars what things are they in nature are they petite things not worth our notice or grand and worthy of consideration SIMPL. They are principal noble integral bodies of the Universe most vast and considerable SAGR. And Motion and Rest what accidents are they in Nature SIMPL. So great and principal that Nature her self is defined by them SAGR. So that moving eternally and the being wholly immoveable are two conditions very considerable in Nature and indicate very great diversity and especially when ascribed to the principal bodies of the Universe from which can ensue none but very different events SIMPL. Yea doubtlesse SAGR. Now answer me to another point Do you believe that in Logick Rhethorick the Physicks Metaphysicks Mathematicks and finally in the universaâ—ity of Disputations there are arguments sufficient to perswade and demonstrate to a person the fallacious no lesse then the true conclusions SIMPL. No Sir rather I am very confident and certain that for the proving of a true and necessary conclusion there are in nature not onely one but many very powerfull demonstrations and that one may discusse and handle the same divers and sundry wayes without ever falling into any absurdity and that the more
to receive every impulse and also to retain the same SALV But if those penduli even now named did prove unto us that the moveable the lesse it had of gravity the lesse apt it was to conserve its motion how can it be that the Air which in the Air hath no gravity at all doth of it self alone retain the motion acquired I believe and know that you by this time are of the same opinion that the arm doth not sooner return to rest than doth the circumambient Air. Let 's go into the Chamber and with a towel let us agitate the Air as much as we can and then holding the cloth still let a little candle be brought that was lighted in the next room or in the same place let a leaf of beaten Gold be left at liberty to flie any way and you shall by the calm vagation of them be assured that the Air is immediately reduced to tranquilty I could alledg many other experiments to the same purpose but if one of these should not suffice I should think your folly altogether incurable SAGR. When an arrow is shot against the Wind how incredible a thing is it that that same small filament of air impelled by the bow-string should in despite of fate go along with the arrow But I would willingly know another particular of Aristotle to which I intreat Simplicius would vouchsafe me an answer Supposing that with the same Bow there were shot two arrows one just after the usual manner and the other side-wayes placing it long-wayes upon the Bow-string and then letting it flie I would know which of them would go farthest Favour me I pray you with an answer though the question may seem to you rather ridiculous than otherwise and excuse me for that I who am as you see rather blockish than not can reach no higher with my speculative faculty SIMPL. I have never seen an arrow shot in that manner yet neverthelesse I believe that it would not flie side-long the twentieth part of the space that it goeth end-wayes SAGR. And for that I am of the same opinion hence it is that I have a doubt risen in me whether Aristotle doth not contradict experience For as to experience if I lay two arrows upon this Table in a time vvhen a strong Wind blovveth one tovvards the course of the wind and the other sidelong the wind will quickly carry away this later and leave the other where it was and the same to my seeming ought to happen if the Doctrine of Aristotle were true of those two shot out of a Bow forasmuch as the arrow shot sideways is driven by a great quantity of Air moved by the bowstring to wit by as much as the said string is long whereas the other arrow receiveth no greater a quantity of air than the small circle of the strings thickness And I cannot imagine what may be the reason of such a difference but would fain know the same SIMP The cause seemeth to me sufficiently manifest and it is because the arrow shot endways hath but a little quantity of air to penetrate and the other is to make its way through a quantity as great as its whole length SALV Then it seems the arrows shot are to penetrate the air but if the air goeth along with them yea is that which carrieth them what penetration can they make therein Do you not see that in this case the arrow would of necessity move with greater velocity than the air and this greater velocity what doth confer it on the arrow Will you say the air giveth them a velocity greater than its own Know then Simplicius that the business proceeds quite contrary to that which Aristotle saith and that the medium conferreth the motion on the project is as false as it is true that it is the onely thing which procureth its obstruction and having known this you shall understand without finding any thing whereof to make question that if the air be really moved it doth much better carry the dart along with it longways than endways for that the air which impelleth it in that posture is much and in this very little But shooting with the Bow forasmuch as the air stands still the transverse arrow being to force its passage through much air comes to be much impeded and the other that was nock't easily overcometh the obstruction of the small quantity of air which opposeth it self thereto SALV How many Propositions have I observed in Aristotle meaning still in Natural Philosophy that are not onely false but false in such sort that its diametrical contrary is true as it happens in this case But pursuing the point in hand I think that Simplicius is perswaded that from seeing the stone always to fall in the same place he cannot conjecture either the motion or stability of the Ship and if what hath been hitherto spoken should not suffice there is the Experiment of the medium which may thorowly assure us thereof in which experiment the most that could be seen would be that the cadent moveable might be left behind if it were light and that the air did not follow the motion of the ship but in case the air should move with equal velocity no imaginable diversity could be found either in this or any other experiment whatsoever as I am anon to tell you Now if in this case there appeareth no difference at all what can be pretended to be seen in the stone falling from the top of the Tower where the motion in gyration is not adventitious and accidental but natural and eternal and where the air exactly followeth the motion of the Tower and the Tower that of the Terrestrial Globe have you any thing else to say Simplicius upon this particular SIMP No more but this that I see not the mobility of the Earth as yet proved SALV Nor have I any intention at this time but onely to shew that nothing can be concluded from the experiments alledged by our adversaries for convincing Arguments as I think I shall prove the others to be SAGR. I beseech you Salviatus before you proceed any farther to permit me to start certain questions which have been rouling in my fancy all the while that you with so much patience and equanimity was minutely explaining to Simplicius the experiment of the Ship SALV We are here met with a purpose to dispute and it 's fit that every one should move the difficulties that he mets withall for this is the way to come to the knowledg of the truth Therefore speak freely SAGR. If it be true that the impetus wherewith the ship moves doth remain indelibly impress'd in the stone after it is let fall from the Mast and if it be farther true that this motion brings no impediment or retardment to the motion directly downwards natural to the stone it 's necessary that there do an effect ensue of a very wonderful nature Let a Ship be supposed to stand still and
in the whole time AK is as the line KL in respect to the degree HI acquired in the time AH and the degree FG in the time AF the which degrees KL HI FG are as is manifest the same in proportion as the times KA HA FA and if other perpendiculars were drawn from the points marked at pleasure in the line FA one might successively find degrees lesse and lesse in infinitum proceeding towards the point A representing the first instant of time and the first state of rest And this retreat towards A representeth the first propension to the motion of descent diminished in infinitum by the approach of the moveable to the first state of rest which approximation is augmentable in infinitum Now let us find the other diminution of velocity which likewise may proceed to infinity by the diminution of the gravity of the moveable and this shall be represented by drawing other lines from the point A which contein angles lesse than the angle BAE which would be this line AD the which intersecting the parallels KL HI FG in the points M N and O represent unto us the degrees FO HN KM acquired in the times AF AH AK lesse than the other degrees FG HI KL acquired in the same times but these latter by a moveable more ponderous and those other by a moveable more light And it is manifest that by the retreat of the line EA towards AB contracting the angle EAB the which may be done in infinitum like as the gravity may in infinitum be diminished the velocity of the cadent moveable may in like manner be diminished in infinitum and so consequently the cause that impeded the projection and therefore my thinks that the union of these two reasons against the projection diminished to infinity cannot be any impediment to the said projection And couching the whole argument in its shortest terms we will say that by contracting the angle EAB the degrees of velocity LK IH GF are diminished and moreover by the retreat of the parallels KL HI FG towards the angle A the same degrees are again diminished and both these diminutions extend to infinity Therefore the velocity of the motion of descent may very well diminish so much it admitting of a twofold diminution in infinitum as that it may not suffice to restore the moveable to the circumference of the wheel and thereupon may occasion the projection to be hindered and wholly obviated Again on the contrary to impede the projection it is necessary that the spaces by which the project is to descend for the reuniting it self to the Wheel be made so short and close together that though the descent of the moveable be retarded yea more diminished in infinitum yet it sufficeth to reconduct it thither and therefore it would be requisite that you find out a diminution of the said spaces not only produced to infinity but to such an infinity as that it may superate the double infinity that is made in the diminution of the velocity of the descending moveable But how can a magnitude be diminished more than another which hath a twofold diminution in infinitum Now let Simplicius observe how hard it is to philosophate well in nature without Geometry The degrees of velocity diminished in infinitum as well by the diminution of the gravity of the moveable as by the approxination to the first term of the motion that is to the state of rest are alwayes determinate and answer in proportion to the parallels comprehended between two right lines that concur in an angle like to the angle BAE or BAD or any other infinitely more acute alwayes provided it be rectilineall But the diminution of the spaces thorow which the moveable is to be conducted along the circumference of the wheel is proportionate to another kind of diminution comprehended between lines that contain an angle infinitely more narrow and acute than any rectilineal angle how acute soever which is that in our present case Let any point be taken in the perpendicular AC and making it the centre describe at the distance CA an arch AMP the which shall intersect the parallels that determine the degrees of velocity though they be very minute and comprehended within a most acute rectilineal angle of which parallels the parts that lie between the arch and the tangent AB are the quantities of the spaces and of the returns upon the wheel alwayes lesser and with greater proportion lesser by how much neerer they approach to the contact than the said parallels of which they are parts The parallels comprehended between the right lines in retiring towards the angle diminish alwayes at the same rate as v. g. AH being divided in two equal parts in F the parallel HI shall be double to FG and sub-dividing FA in two equal parts the parallel produced from the point of the division shall be the half of FG and continuing the sub-division in infinitum the subsequent parallels shall be alwayes half of the next preceding but it doth not so fall out in the lines intercepted between the tangent and the circumference of the circle For if the same sub-division be made in FA and supposing for example that the parallel which cometh from the point H were double unto that which commeth from F this shall be more then double to the next following and câ—â—â—inually the neerer we come towards the contact A we shall fiâ—â— the precedent lines contein the next following three four ten an hundred a thousand an hundred thousand an hundred millions of times and more in infinitum The brevity therefore of such lines is so reduced that it far exceeds what is requisite to make the project though never so light return nay more continue unremoveable upon the circumference SAGR. I very well comprehend the whole discourse and upon what it layeth all its stresse yet neverthelesse methinks that he that would take pains to pursue it might yet start some further questions by saying that of those two causes which render the descent of the moveable slower and slower in infinitum it is manifest that that which dependeth on the vicinity to the first term of the descent increaseth alwayes in the same proportion like as the parallels alwayes retain the same proportion to each other c. but that the diminution of the same velocity dependent on the diminution of the gravity of the moveable which vvas the second cause doth also observe the same proportion doth not so plainly appear And vvho shall assure us that it doth not proceed according to the proportion of the lines intercepted between the secant and the circumference or vvhether vvith a greater proportion SALV I have assumed for a truth that the velocities of moveables descending naturally vvill follovv the proportion of their gravities with the favour of Simplicius and of Aristotle who doth in many places affirm the same as a proposition manifest You in favour of my adversary bring the same into question
and say that its possible that the velocity increaseth with greater proportion yea and greater in infinitum than that of the gravity so that all that hath been said falleth to the ground For maintaining whereof I say that the proportion of the velocities is much lesse than that of the gravities and thereby I do not onely support but confirme the premises And for proof of this I appeal unto experience which will shew us that a grave body howbeit thirty or fourty times bigger then another as for example a ball of lead and another of sugar will not move much more than twice as fast Now if the projection would not be made albeit the velocity of the cadent body should diminish according to the proportion of the gravity much lesse would it be made so long as the velocity is but little diminished by abating much from the gravity But yet supposing that the velocity diminisheth with a proportion much greater than that wherewith the gravity decreaseth nay though it were the self-same wherewith those parallels conteined between the tangent and circumference do decrease yet cannot I see any necessity why I should grant the projection of matters of never so great levity yea I farther averre that there could no such projection follow meaning alwayes of matters not properly and absolutely light that is void of all gravity and that of their own natures move upwards but that descend very slowly and have very small gravity And that which moveth me so to think is that the diminution of gravity made according to the proportion of the parallels between the tangent and the circumference hath for its ultimate and highest term the nullity of weight as those parallels have for their last term of their diminution the contact it self which is an indivisible point Now gravity never diminisheth so far as to its last term for then the moveable would cease to be grave but yet the space of the reversion of the project to the circumference is reduced to the ultimate minuity which is when the moveable resteth upon the circumference in the very point of contact so as that to return thither it hath no need of space and therefore let the propension to the motion of descent be never so small yet is it alwayes more than sufficient to reconduct the moveable to the circumference from which it is distant but its least space that is nothing at all SAGR. Your discourse I must confess is very accurate and yet no less concluding than it is ingenuous and it must be granted that to go about to handle natural questions without Geometry is to attempt an impossibility SALV But Simplicius will not say so and yet I do not think that he is one of those Peripateticks that disswade their Disciples from studying the Mathematicks as Sciences that vitiate the reason and render it lesse apt for contemplation SIMP I would not do so much wrong to Plato but yet I may truly say with Aristotle that he too much lost himself in and too much doted upon that his Geometry for that in conclusion these Mathematical subtilties Salviatus are true in abstract but applied to sensible and Physical matter they hold not good For the Mathematicians will very well demonstrate for example that Sphaera tangit planum in puncto a position like to that in dispute but when one cometh to the matter things succeed quite another way And so I may say of these angles of contact and these proportions which all evaporate into Air when they are applied to things material and sensible SALV You do not think then that the tangent toucheth the superficies of the terrestrial Globe in one point only SIMP No not in one sole point but I believe that a right line goeth many tens and hundreds of yards touching the surface not onely of the Earth but of the water before it separate from the same SALV But if I grant you this do not you perceive that it maketh so much the more against your cause For if it be supposed that the tangent was separated from the terrestrial superficies yet it hath been however demonstrated that by reason of the great acuity of the angle of contingence if happily it may be call'd an angle the project would not separate from the same how much lesse cause of separation would it have if that angle should be wholly closed and the superficies and the tangent become all one Perceive you not that the Projection would do the same thing upon the surface of the Earth which is asmuch as to say it would do just nothing at all You see then the power of truth which while you strive to oppose it your own assaults themselves uphold and defend it But in regard that you have retracted this errour I would be loth to leave you in that other which you hold namely that a material Sphere doth not touch a plain in one sole point and I could wish some few hours conversation with some persons conversant in Geometry might make you a little more intelligent amongst those who know nothing thereof Now to shew you how great their errour is who say that a Sphere v. g. of brasse doth not touch a plain v. g. of steel in one sole point Tell me what conceipt you would entertain of one that should constantly aver that the Sphere is not truly a Sphere SIMP I would esteem him wholly devoid of reason SALV He is in the same case who saith that the material Sphere doth not touch a plain also material in one onely point for to say this is the same as to affirm that the Sphere is not a Sphere And that this is true tell me in what it is that you constitute the Sphere to consist that is what it is that maketh the Sphere differ from all other solid bodies SIMP I believe that the essence of a Sphere consisteth in having all the right lines produced from its centre to the circumference equal SALV So that if those lines should not be equal that same solidity would be no longer a sphere SIMP True SALV Go to tell me whether you believe that amongst the many lines that may be drawn between two points there may be more than one right line onely SIMP There can be but one SALV But yet you understand that this onely right line shall again of necessity be the shortest of them all SIMP I know it and also have a demonstration thereof produced by a great Peripatetick Philosopher and as I take it if my memory do not deceive me he alledgeth it by way of reprehending Archimedes that supposeth it as known when it may be demonstrated SALV This must needs be a great Mathematician that knew how to demonstrate that which Archimedes neither did nor could demonstrate And if you remember his demonstration I would gladly hear it for I remember very well that Archimedes in his Books de Sphaerâ— Cylindro placeth this Proposition amongst the Postulata
worth than the wool of a goat and whereas our argumentations should continually be conversant about serious and weighty points we consume our time in frivolous and impertinent wranglings Let us call to minde I pray you that the search of the worlds constitution is one of the greatest and noblest Problems that are in nature and so much the greater inasmuch as it is directed to the resolving of that other to wit of the cause of the Seas ebbing and flowing enquired into by all the famous men that have hitherto been in the world and possibly found out by none of them Therefore if we have nothing more remaining for the full confutation of the argument taken from the Earths vertigo which was the last alledged to prove its immobility upon its own centre let us passe to the examination of those things that are alledged for and against the Annual Motion SAGR. I would not have you Salviatus measure our wits by the scale of yours you who use to be continually busied about the sublimest contemplations esteem those notions frivolous and below you which we think matters worthy of our profoundest thoughts yet sometimes for our satisfaction do not disdain to stoop so low as to give way a little to our curiosity As to the refutation of the last argument taken from the extrusions of the diurnal vertigo far less than what hath been said would have given me satisfaction and yet the things superfluously spoken seemed to me so ingenious that they have been so far from wearying my fancy as that they have by reason of their novelty entertained me all along with so great delight that I know not how to desire greater Therefore if you have any other speculation to add produce it for I as to my own particular shall gladly hearken to it SALV I have always taken great delight in those things which I have had the fortune to discover and next to that which is my chief content I find great pleasure in imparting them to some friends that apprehendeth and seemeth to like them Now in regard you are one of these slacking a little the reins of my ambition which is much pleased when I shew my self more perspicacious than some other that hath the reputation of a sharp sight I will for a full and true measure of the past dispute produce another fallacy of the Sectators of Ptolomey and Aristotle which I take from the argument alledged SAGR. See how greedily I wait to hear it SALV We have hitherto over-passed and granted to Ptolomey as an effect indubitable that the extrusion of the stone proceeding from the velocity of the wheel turn'd round upon its centre the cause of the said extrusion encreaseth in proportion as the velocity of the vertigo or whirling is augmented from whence it was inferred that the velocity of the Earth's vertigo being very much greater than that of any machin whatsoever that we can make to turn round artificially the extrusion of stones of animals c. would consequently be far more violent Now I observe that there is a great fallacy in this discourse in that we do compare these velocities indifferently and absolutely to one another It 's true that if I compare the velocities of the same wheel or of two wheels equal to each other that which shall be more swiftly turn'd round shall extrude the stone with greater violence and the velocity encreasing the cause of the projection shall likewise encrease but when the velocity is augmented not by encreasing the velocity in the same wheel which would be by causing it to make a greater number of revolutions in equal times but by encreasing the diameter and making the wheel greater so as that the conversion taking up the same time in the lesser wheel as in the greater the velocity is greater onely in the bigger wheel for that its circumference is bigger there is no man that thinketh that the cause of the extrusion in the great wheel will encrease according to the proportion of the velocity of its circumference to the velocity of the circumference of the other lesser wheel for that this is most false as by a most expeditious experiment I shall thus grosly declare We may sling a stone with a stick of a yard long farther than we can do with a stick six yards long though the motion of the end of the long stick that is of the stone placed in the slit thereof were more than double as swift as the motion of the end of the other shorter stick as it would be if the velocities were such that the lesser stick should turn thrice round in the time whilst the greater is making one onely conversion SAGR. This which you tell me Salviatus must I see needs succeed in this very manner but I do not so readily apprehend the cause why equal velocities should not operate equally in extruding projects but that of the lesser wheel much more than the other of the greater wheel therefore I intreat you to tell me how this cometh to pass SIMP Herein Sagredus you seem to differ much from your self for that you were wont to penetrate all things in an instant and now you have overlook'd a fallacy couched in the experiment of the stick which I my self have been able to discover and this is the different manner of operating in making the projection one while with the short sling and another while with the long one for if you will have the stone fly out of the slit you need not continue its motion uniformly but at such time as it is at the swiftest you are to stay your arm and stop the velocity of the stick whereupon the stone which was in its swiftest motion flyeth out and moveth with impetuosity but now that stop cannot be made in the great stick which by reason of its length and flexibility doth not entirely obey the check of the arm but continueth to accompany the stone for some space and holdeth it in with so much less force and not as if you had with a stiff sling sent it going with a jerk for if both the sticks or slings should be check'd by one and the same obstacle I do believe they would fly aswell out of the one as out of the other howbeit their motions were equally swift SAGR. With the permission of Salviatus I will answer something to Simplicius in regard he hath addressed himself to me and I say that in his discourse there is somewhat good and somewhat bad good because it is almost all true bad because it doth not agree with our case Truth is that when that which carrieth the stones with velocity shall meet with a check that is immoveable they shall fly out with great impetuosity the same effect following in that case which we see dayly to fall out in a boat that running a swift course runs a-ground or meets with some sudden stop for all those in the boat being surprized stumble forwards
of the motion of the little pendent weight is an hundred times greater than the velocity of the motion of the sack Now fix it in your belief as a true and manifest axiom that the resistance which proceedeth from the velocity of motion compensateth that which dependeth on the gravity of another moveable So that consequently a moveable of one pound that moveth with an hundred degrees of velocity doth as much resist all obstruction as another moveable of an hundred weight whose velocity is but one degree onely And two equal moveables will equally resist their being moved if that they shall be moved with equal velocity but if one be to be moved more swiftly than the other it shall make greater resistance according to the greater velocity that shall be conferred on it These things being premised let us proceed to the explanation of our Problem and for the better understanding of things let us make a short Scheme thereof Let two unequal wheels be described about this centre A in Fig. 7. and let the circumference of the lesser be BG and of the greater CEH and let the semidiameter ABC be perpendicular to the Horizon and by the points B and C let us draw the right lined Tangents BF and CD and in the arches BG and CE take two equal parts BG and CE and let the two wheels be supposed to be turn'd round upon their centres with equal velocities so as that two moveables which suppose for example to be two stones placed in the points B and C come to be carried along the circumferences BG and CE with equal velocities so that in the same time that the stone B shall have run the arch BG the stone C will have past the arch CE. I say now that the whirl or vertigo of the lesser wheel is much more potent to make the projection of the stone B than the vertigo of the bigger wheel to make that of the stone C. Therefore the projection as we have already declared being to be made along the tangent when the stones B and C are to separate from their wheel and to begin the motion of projection from the points B and C then shall they be extruded by the impetus conceived from the vertigo by or along the tangents BF and CD The two stones therefore have equal impetuosities of running along the tangents BF and CD and would run along the same if they were not turn'd aside by some other force is it not so Sagredus SAGR. In my opinion the businesse is as you say SALV But what force think you should that be which averts the stones from moving by the tangents along which they are certainly driven by the impetus of the vertigo SAGR. It is either their own gravity or else some glutinous matter that holdeth them fast and close to the wheels SALV But for the diverting of a moveable from the motion to which nature inciteth it is there not required greater or lesser force according as the deviation is intended to be greater or lesser that is according as the said moveable in its deviation hath a greater or lesser space to move in the same time SAGR. Yes certainly for it was concluded even now that to make a moveable to move the movent vertue must be increased in proportion to the velocity wherewith it is to move SALV Now consider that for the deviating the stone upon the lesse wheel from the motion of projection which it would make by the tangent BF and for the holding of it fast to the wheel it is required that its own gravity draw it back the whole length of the secant FG or of the perpendicular raised from the point G to the line BF whereas in the greater wheel the retraction needs to be no more than the secant DE or the perpendicular let fall from the tangent DC to the point E lesse by much than FG and alwayes lesser and lesser according as the wheel is made bigger And forasmuch as these retractions as I may call them are required to be made in equal times that is whil'st the wheels passe the two equal arches BG and CE that of the stone B that is the retraction FG ought to be more swift than the other DE and therefore much greater force will be required for holding fast the stone B to its little wheel than for the holding the stone C to its great one which is as much as to say that such a small thing will impede the extrusion in the great wheel as will not at all hinder it in the little one It is manifest therefore that the more the wheel augmenteth the more the cause of the projection diminisheth SAGR. From this which I now understand by help of your minute dissertation I am induced to think that I am able to satisfie my judgment in a very few words For equal impetus being impressed on both the stones that move along the tangents by the equal velocity of the two wheels we see the great circumference by means of its small deviation from the tangent to go seconding as it were and in a fair way refraining in the stone the appetite if I may so say of separating from the circumference so that any small retention either of its own inclination or of some glutination sufficeth to hold it fast to the wheel Which again is not able to work the like effect in the little wheel which but little prosecuting the direction of the tangent seeketh with too much eagernesse to hold fast the stone and the restriction and glutination not being stronger than that which holdeth the other stone fast to the greater wheel it breaks loose and runneth along the tangent Therefore I do not only finde that all those have erred who have believed the cause of the projection to increase according to the augmentation of the vertigo's velocity but I am further thinking that the projection diminishing in the inlarging of the wheel so long as the same velocity is reteined in those wheels it may possibly be true that he that would make the great wheel extrude things like the little one would be forced to increase them as much in velocity as they increase in diameter which he might do by making them to finish their conversions in equal times and thus we may conclude that the Earths revolution or vertigo would be no more able to extrude stones than any little wheel that goeth so slowly as that it maketh but one turn in twenty four hours SALV We will enquire no further into this point for the present let it suffice that we have abundantly if I deceive not my self demonstrated the invalidity of the argument which at first sight seemed very concluding and was so held by very famous men and I shall think my time and words well bestowed if I have but gained some belief in the opinion of Simplicius I will not say of the Earths mobility but only that the opinion
two angles A and E to be greater than two right angles the observations without more adoe will prove erroneous This is that which I had a desire that you should perfectly understand and which I doubted that I was not able so to make out as that a meer Peripatetick Philosopher might attain to the certain knowledg thereof Now let us go on to what remains And re-assuming that which even now you granted me namely that the new star could not possibly be in many places but in one alone when ever the supputations made upon the observations of these Astronomers do not assign it the same place its necessary that it be an errour in the observations that is either in taking the altitudes of the pole or in taking the elevations of the star or in the one or other working Now for that in the many workings made with the combinations two by two there are very few of the observations that do agree to place the star in the same situation therefore these few onely may happily be the non-erroneous but the others are all absolutely false SAGR. It will be necessary then to give more credit to these few alone than to all the rest together and because you say that these which accord are very few and I amongst these 12 do find two that so accord which both make the distance of the star from the centre of the Earth 4 semidiameters which are these the fifth and sixth therefore it is more probable that the new star was elementary than celestial SALV You mistake the point for if you note well it was not written that the distance was exactly 4 semidiameters but about 4 semidiameters and yet you shall see that those two distances differed from each other many hundreds of miles Here they are you see that this fifth which is 13389 Italian miles exceeds the sixth which is 13100 miles by almost 300 miles SAGR. Which then are those few that agree in placing the star in the same situation SALV They are to the disgrace of this Author five workings which all place it in the firmament as you shall see in this note where I have set down many other combinations But I will grant the Author more than peradventure he would demand of me which is in sum that in each combination of the observations there is some error which I believe to be absolutely necessary for the observations being four in number that serve for one working that is two different altitudes of the Pole and two different elevations of the star made by different obfervers in different places with different instruments who ever hath any small knowledg of this art will say that amongst all the four it is impossible but there will be some error and especially since we see that in taking but one onely altitude of the Pole with the same instrument in the same place by the same observer that hath repeated the observation a thousand times there will still be a titubation of one or sometimes of many minutes as in this same book you may see in several places These things presupposed I ask you Simplicius whether you believe that this Authour held these thirteen observators for wise understanding and expert men in using those instruments or else for inexpert and bunglers SIMP It must needs be that he esteemed them very acute and intelligent for if he had thought them unskilful in the businesse he might have omitted his sixth book as inconclusive as being founded upon suppositions very erroneous and might take us for excessively simple if he should think he could with their inexpertnesse perswade us to believe a false position of his for truth SALV Therefore these observators being such and that yet notwithstanding they did erre and so consequently needed correction that so one might from their observations infer the best hints that may be it is convenient that we apply unto them the least and neerest emendations and corrections that may be so that they do but suffice to reduce the observations from impossibility to possibility so as v. gr if one may but correct a manifest errour and an apparent impossibility of one of their observations by the addition or substraction of two or three minutes and with that amendment to reduce it to possibility a man ought not to essay to adjust it by the addition or substraction of fifteen twenty or fifty SIMP I think the Author would not deny this for granting that they are expert and judicious men it ought to be thought that they did rather erre little than much SALV Observe again The places where the new Star is placed are some of them manifestly impossible and others possible Absolutely impossible it is that it should be an infinite space superiour to the fixed Stars for there is no such place in the world and if there were the Star there scituate would have been imperceptible to us it is also impossible that it should go creeping along the superficies of the Earth and much lesse that it should be within the said Terrestrial Globe Places possible are these that be in controversie it not interferring vvith our understanding that a visible object in the likenesse of a Star might be aswell above the Moon as below it Now whilst one goeth about to compute by the way of Observations and Calculations made with the utmost certainty that humane diligence can attain unto what its place was it is found that the greatest part of those Calculations make it more than infinitely superiour to the Firmament others make it very neer to the surface of the Earth and some also under the same and of the rest which place it in situations not impossible none of them agree with each other insomuch that it must be confessed hat all those observations are necessarily false so that if we would nevertheless collect some fruit from so many laborious calculations we must have recourse to the corrections amending all the observations SIMP But the Authour will say that of the observations that assign to the Star impossible places there ought no account to be made as being extreamly erroneous and false and those onely ought to be accepted that constitute it in places not impossible and amongst these a man ought to seek by help of the most probable and most numerous concurrences not if the particular and exact situation that is its true distance from the centre of the Earth at least whether it was amongst the Elements or else amongst the Coelestial bodies SALV The discourse which you now make is the self same that the Author made in favour of his cause but with too unreasonable a disadvantage to his adversaries and this is that principal point that hath made me excessively to wonder at the too great confidence that he expressed to have no less of his own authority than of the blindness and inadvertency of the Astronomers in favour of whom I will speak and you shall answer for the Author And first
Copernicus hath been the first that hath made the reason plain unto us But of another effect no lesse admirable than this and that with a knot perhaps more difficult to unknit bindeth the wit of man to admit this annual conversion and to leave it to our Terrestrial Globe a new and unthought of conjecture ariseth from the Sun it self which sheweth that it is unwilling to be singular in shifting of this attestation of so eminent a conclusion rather as a testimony beyond all exception it hath desired to be heard apart Hearken then to this great and new wonder The first discoverer and observer of the Solar spots as also of all the other Coelestial novelties was our Academick Lincaeus and he discovered them anno 1610. being at that time Reader of the Mathematicks in the Colledge of Padua and there and in Venice he discoursed thereof with several persons of which some are yet living And the year following he shewed them in Rome to many great personages as he relates in the first of his Letters to Marcus Velserus Sheriffe of Augusta He was the first that against the opinions of the too timorous and too jealous assertors of the Heavens inalterability affirmed those spots to be matters that in short times were produced and dissolved for as to place they were contiguous to the body of the Sun and revolved about the same or else being carried about by the said Solar body which revolveth in it selfe about its own Centre in the space almost of a moneth do finish their course in that time which motion he judged at first to have been made by the Sun about an Axis erected upon the plane of the Ecliptick in regard that the arches described by the said spots upon the Discus of the Sun appear unto our eye right lines and parallels to the plane of the Ecliptick which therefore come to be altered in part with some accidental wandring and irregular motions to which they are subject and whereby tumultuarily and without any order they successively change situations amongst themselves one while crouding close together another while dissevering and some dividing themselves into many and very much changing figures which for the most part are very unusual And albeit those so inconstant mutations did somewhat alter the primary periodick course of the said spots yet did they not alter the opinion of our friend so as to make him believe that they were any essential and fixed cause of those deviations but he continued to hold that all the apparent alterations derived themselves from those accidental mutations in like manner just as it would happen to one that should from far distant Regions observe the motion of our Clouds which would be discovered to move with a most swift great and constant motion carried round by the diurnal Vertigo of the Earth if haply that motion belong to the same in twenty four hours by circles parallel to the Equinoctial but yet altered in part by the accidental motions caused by the winds which drive them at all adventures towards different quarters of the World While this was in agitation it came to pass that Velserus sent him two Letters written by a certain person under the feigned name of Apelles upon the subject of these Spots requesting him with importunity to declare his thoughts freely upon those Letters and withall to let him know what his opinion was touching the essence of those spots which his request he satisfied in 3 Letters shewing first of all howvain the conjectures of Apelles were discovering secondly his own opinions withal foretelling to him that Apelles would undoubtedly be better advised in time and turn to his opinion as it afterwards came to pass And because that our Academian as it was also the judgment of many others that were intelligent in Natures secrets thought he had in those three Letters investigated and demonstrated if not all that could be desired or required by humane curiosity at least all that could be attained by humane reason in such a matter he for some time being bufied in other studies intermitted his continual observations and onely in complacency to some friend joyned with him in making now and then an abrupt observation till that he and after some years we being then at my Country-seat met with one of the solitary Solar spots very big and thick invited withal by a clear and constant serenity of the Heavens he at my request made observations of the whole progresse of the said spot carefully marking upon a sheet of paper the places that it was in every day at the time of the Suns coming into the Meridian and we having found that its course was not in a right line but somewhat incurvated we came to resolve at last to make other observations from time to time to which undertaking we were strongly induced by a conceit that accidentally came into the minde of my Guest which he imparted to me in these or the like words In my opinion Philip there is a way opened to a business of very great consequence For if the Axis about which the Sun turneth be not erect perpendicularly to the plane of the Ecliptick but is inclined upon the same as its crooked course but even now observed makes me believe we shall be able to make such conjectures of the states of the Sun and Earth as neither so solid or so rational have been hitherto deduced from any other accident whatsoever I being awakened at so great a promise importun'd him to make a free discovery of his conceit unto me And he continued his discourse to this purpose If the Earths motion were along the Ecliptique about the Sun and the Sun were constituted in the centre of the said Ecliptick and therein revolved in its self not about the Axis of the said Ecliptique which would be the Axis of the Earths annual motion but upon one inclined it must needs follow that strange changes will represent themselves to us in the apparent motions of the Solar spots although the said Axis of the Sun should be supposed to persist perpetually and immutably in the same inclination and in one and the same direction towards the self-same point of the Universe Therefore the Terrestrial Globe in the annual motion moving round it it will first follow that to us carried about by the same the courses of the spots shall sometimes seem to be made in right lines but this only twice a year and at all other times shall appear to be made by arches insensibly incurvated Secondly the curvity of those arches for one half of the year will shew inclined the contrary way to what they will appear in the other half that is for six moneths the convexity of the arches shall be towards the upper part of the Solar Discus and for the other six moneths towards the inferiour Thirdly the spots beginning to appear and if I may so speak to rise to our eye from
a very exact observation and of great consequence we are advertized to make the observation of that concourse in the act of the same or just such another operation but in this our case wherein we are to shew the errour of Astronomers this accuratenesse is not necessary for though we should in favour of the contrary party suppose the said concourse to be made upon the pupil it self it would import little their mistake being so great I am not certain Sagredus that this would have been your objection SAGR. It is the very same and I am glad that it was not altogether without reason as your concurrence in the same assureth me but yet upon this occasion I would willingly hear what way may be taken to finde out the distance of the concourse of the visual rayes SALV The method is very easie and this it is I take two long labels of paper one black and the other white and make the black half as broad as the white then I stick up the white against a wall and far from that I place the other upon a stick or other support at a distance of fifteen or twenty yards and receding from this second another such a space in the same right line it is very manifest that at the said distance the right lines will concur that departing from the termes of the breadth of the white piece shall passe close by the edges of the other label placed in the mid-way whence it followeth that in case the eye were placed in the point of the said concourse or intersection the black slip of paper in the midst would precisely hide the opposite blank if the sight were made in one onely point but if we should find that the edges of the white cartel appear discovered it shall be a necessary argument that the visual rayes do not issue from one sole point And to make the white label to be hid by the black it will be requisite to draw neerer with the eye Therefore having approached so neer that the intermediate label covereth the other and noted how much the required approximation was the quantity of that approach shall be the certain measure how much the true concourse of the visive rayes is remote from the eye in the said operation and we shall moreover have the diameter of the pupil or of that circlet from whence the visive rayes proceed for it shall be to the breadth of the black paper as is the distance from the concourse of the lines that are produced by the edges of the papers to the place where the eye standeth when it first seeth the remote paper to be hid by the intermediate one as that distance is I say to the distance that is between those two papers And therefore when we would with exactnesse measure the apparent diameter of a Star having made the observation in manner as aforesaid it would be necessary to compare the diameter of the rope to the diameter of the pupil and having found v. g. the diameter of the rope to be quadruple to that of the pupil and the distance of the eye from the rope to be for example thirty yards we would say that the true concourse of the lines produced from the ends or extremities of the diameter of the star by the extremities of the diameter of the rope doth fall out to be fourty yards remote from the said rope for so we shall have observed as we ought the proportion between the distance of the rope from the concourse of the said lines and the distance from the said concourse to the place of the eye which ought to be the same that is between the diameter of the rope and diameter of the pupil SAGR. I have perfectly understood the whole businesse and therefore let us hear what Simplicius hath to alledge in defence of the Anti-Copernicans SIMP Albeit that grand and altogether incredible inconvenience insisted upon by these adversaries of Copernicus be much moderated and abated by the discourse of Salviatus yet do I not think it weakened so as that it hath not strength enough left to foil this same opinion For if I have rightly apprehended the chief and ultimate conclusion in case the stars of the sixth magnitude were supposed to be as big as the Sun which yet I can hardly think yet it would still be true that the grand Orb or Ecliptick would occasion a mutation and variation in the starry Sphere like to that which the semidiameter of the Earth produceth in the Sun which yet is observable so that neither that no nor a lesse mutation being discerned in the fixed Stars methinks that by this means the annual motion of the Earth is destroyed and overthrown SALV You might very well so conclude Simplicius if we had nothing else to say in behalf of Copernicus but we have many things to alledge that yet have not been mentioned and as to that your reply nothing hindereth but that we may suppose the distance of the fixed Stars to be yet much greater than that which hath been allowed them and you your self and whoever else will not derogate from the propositions admitted by Piolomy's sectators must needs grant it as a thing most requisite to suppose the Starry Sphere to be very much bigger yet than that which even now we said that it ought to be esteemed For all Astronomers agreeing in this that the cause of the greater tardity of the Revolutions of the Planets is the majority of their Spheres and that therefore Saturn is more slow than Jupiter and Jupiter than the Sun for that the first is to describe a greater circle than the second and that than this later c. confidering that Saturn v. g. the altitude of whose Orb is nine times higher than that of the Sun and that for that cause the time of one Revolution of Saturn is thirty times longer than that of a conversion of the Sun in regard that according to the Doctrine of Ptolomy one conversion of the starry Sphere is finished in 36000. years whereas that of Saturn is consummate in thirty and that of the Sun in one arguing with a like proportion and saying if the Orb of Saturn by reason it is nine times bigger than that of the Sun revolves in a time thirty times longer by conversion how great ought that Orb to be which revolves 36000. times more slowly it shall be found that the distance of the starry Sphere ought to be 10800 semidiameters of the grand Orb which should be full five times bigger than that which even now we computed it to be in case that a fixed Star of the sixth magnitude were equal to the Sun Now see how much lesser yet upon this account the variation occasioned in the said Stars by the annual motion of the Earth ought to appear And if at the same rate we would argue the distance of the starry Sphere from Jupiter and from Mars that would give it us
do not happen in our Mediterranean Sea yet doth not this invalidate the reason and cause that I shall produce if so be that it verifie and fully resolve the accidents which evene in our Sea for that in conclusion there can be but one true and primary cause of the effects that are of the same kind I will relate unto you therefore the effects that I know to be true and assigne the causes thereof that I think to be true and you also Gentlemen shall produce such others as are known to you besides mine and then we will try whether the cause by me alledged may satisfie them also I therefore affirm the periods that are observed in the fluxes and refluxes of the Sea-waters to be three the first and principal is this great and most obvious one namely the diurnal according to which the intervals of some hours with the waters flow and ebbe and these intervals are for the most part in the Mediterrane from six hours to six hours or thereabouts that is they for six hours flow and for six hours ebbe The second period is monethly and it seemes to take its origen from the motion of the Moon not that it introduceth other motions but only altereth the greatnesse of those before mentioned with a notable difference according as it shall wax or wane or come to the Quadrature with the Sun The third Period is annual and is seen to depend on the Sunne and onely altereth the diurnal motions by making them different in the times of the Solstices as to greatnesse from what they are in the Equinoxes We will speak in the first place of the diurnal motion as being the principal and upon which the Moon and Sun seem to exercise their power secondarily in their monethly and annual alterations Three differences are observable in these horary mutations for in some places the waters rise and fall without making any progressive motion in others without rising or falling they run one while towards the East and recur another while towards the West and in others they vary the heights and course also as happeneth here in Venice where the Tides in coming in rise and in going out fall and this they do in the extermities of the lengths of Gulphs that distend from West to East and terminate in open shores up along which shores the Tide at time of flood hath room to extend it self but if the course of the Tide were intercepted by Cliffes and Banks of great height and steepnesse there it will flow and ebbe without any progressive motion Again it runs to and again without changing height in the middle parts of the Mediterrane as notably happeneth in the Faro de Messina between Scylla and Carybdis where the Currents by reason of the narrownesse of the Channel are very swift but in the more open Seas and about the Isles that stand farther into the Mediterranean Sea as the Baleares Corsica Sardignia Elba Sicily towards the Affrican Coasts Malta Candia c. the changes of watermark are very small but the currents indeed are very notable and especially when the Sea is pent between Islands or between them and the Continent Now these onely true and certain effects were there no more to be observed do in my judgment very probably perswade any man that will contain himself within the bounds of natural causes to grant the mobility of the Earth for to make the vessel as it may be called of the Mediterrane stand still and to make the water contained therein to do as it doth exceeds my imagination and perhaps every mans else who will but pierce beyond the rinde in these kind of inquiries SIMP These accidents Salviatus begin not now they are most ancient and have been observed by very many and several have attempted to assigne some one some another cause for the same and there dwelleth not many miles from hence a famous Peripatetick that alledgeth a cause for the same newly fished out of a certain Text of Aristotle not well understood by his Expositors from which Text he collecteth that the true cause of these motions doth only proceed from the different profundities of Seas 〈…〉 waters of greatest depth being greater in abundance and therefore more grave drive back the Waters of lesse depth which being afterwards raised desire to descend and from this continual colluctation or contest proceeds the ebbing and flowing Again those that referre the same to the Moon are many saying that she hath particular Domination over the Water and at last a certain Prelate hath published a little Treatise wherâ—in he saith that the Moon wandering too and fro in the Heavens attracteth and draweth towards it a Masse of Water which goeth continually following it so that it is full Sea alwayes in that part which lyeth under the Moon and because that though she be under the Horizon yet neverthelesse the Tide returneth he saith that no more can be said for the salving of that particular save onely that the Moon doth not onely naturally retain this faculty in her self but in this case hath power to confer it upon that degree of the Zodiack that is opposite unto it Others as I believe you know do say that the Moon is able with her temperate heat to rarefie the Water which being rarefied doth thereupon flow Nor hath there been wanting some that SAGR. I pray you Simplicius let us hear no more of them for I do not think it is worth the while to wast time in relating them or to spend our breath in confuting them and for your part if you gave your assent to any of these or the like fooleâ—ies you did a great injury to your judgment which neverthelesse I acknowledg to be very piercing SALV But I that am a little more flegmatick than you Sagredus will spend a few words in favour of Simplicius if haply he thinks that any probability is to be found in those things that he hath related I say therefore The Waters Simplicius that have their exteriour superficies higher repel those that are inferiour to them and lower but so do not those Waters that are of greatest profundity and the higher having once driven back the lower they in a short time grow quiet and level This your Peripatetick must needs be of an opinion that all the Lakes in the World that are in a calme and that all the Seas where the ebbing and flowing is insensible are level in their bottoms but I was so simple that I perswaded my self that had we no other plummet to sound with the Isles that advance so high above Water had been a sufficient evidence of the unevennesse of their bottomes To that Prelate I could say that the Moon runneth every day along the whole Mediterrane and yet its Waters do not rise thereupon save onely in the very extream bounds of it Eastward and here to us at Venice And for those that make the Moons
temperate heat able to make the Water swell bid them put fire under a Kettle full of Water and hold their right hand therein till that the Water by reason of the heat do rise but one sole inch and then let them take it out and write off the tumefaction of the Sea Or at least desire them to shew you how the Moon doth to rarefie a certain part of the Waters and not the remainder as for instance these here of Venice and not those of Ancona Naples Genova the truth is Poetick Wits are of two kinds some are ready and apt to invent Fables and others disposed and inclined to believe them SIMP I believe that no man believeth Fables so long as he knows them to be so and of the opinions concerning the causes of ebbing and flowing which are many because I know that of one single effect there is but one single cause that is true and primary I understand very well and am certain that but one alone at the most can be true and for all the rest I am sure that they are fabulous and false and its possible that the true one may not be among those that have been hitherto produced nay I verily believe that it is not for it would be very strange that the truth should have so little light as that it should not be visible amongst the umbrages of so many falshoods But this I shall say with the liberty that is permitted amongst us that the introduction of the Earths motion and the making it the cause of the ebbing and flowing of Tides seemeth to me as yet a conjecture no lesse fabulous than the rest of those that I have heard and if there should not be proposed to me reasons more conformable to natural matters I would without any more ado proceed to believe this to be a supernatural effect and therefore miraculous and unsearchable to the understandings of men as infinite others there are that immediately depend on the Omnipotent hand of God SAGR. You argue very prudently and according to the Doctrine of Aristotle who you know in the beginning of his mechanical questions referreth those things to a Miracle the causes whereof are occult But that the cause of the ebbing and flowing is one of those that are not to be found out I believe you have no greater proof than onely that you see that amongst all those that have hitherto been produced for true causes thereof there is not one wherewith working by what artifice you will we are able to represent such an effect in regard that neither with the light of the Moon nor of the Sun nor with temperate heats nor with different profundities shall one ever artificially make the Water conteined in an immoveable Vessel to run one way or another and to ebbe and flow in one place and not in another But if without any other artifice but with the onely moving of the Vessel I am able punctually to represent all those mutations that are observed in the Sea Water why will you refuse this reason and run to a Miracle SIMP I will run to a Miracle still if you do not with some other natural causes besides that of the motion of the Vessels of the Sea-water disswade me from it for I know that those Vessels move not in regard that all the entire Terrestrial Globe is naturally immoveable SALV But do not you think that the Terrestrial Globe might supernaturally that is by the absolute power of God be made moveable SIMP Who doubts it SALV Then Simplicius seeing that to make the flux and reflux of the Sea it is necessary to introduce a Miracle let us suppose the Earth to move miraculously upon the motion of which the Sea moveth naturally and this effect shall be also the more simple and I may say natural amongst the miraculous operations in that the making a Globe to move round of which kind we see many others to move is lesse difficult than to make an immense masse of water go forwards and backwards in one place more swiftly and in another lesse and to rise and fall in some places more in some lesse and in some not at all and to work all these different effects in one and the same Vessel that containeth it besides that these are several Miracles and that is but one onely And here it may be added that the Miracle of making the water to move is accompanied with another namely the holding of the Earth stedfast against impetuosities of the water able to make it swage sometimes one way and sometimes another if it were not miraculously kept to rights SAGR. God Simplicius let us for the present suspend our judgement about sentencing the new opinion to be vain that Salviatus is about to explicate unto us nor let us so hastily flye out into passion like the scolding overgrown Haggs and as for the Miracle we may as well recurre to it when we have done hearing the Discourses contained within the bounds of natural causes though to speak freely all the Works of nature or rather of God are in my judgement miraculous SALV And I am of the same opinion nor doth my saying that the motion of the Earth is the Natural cause of the ebbing and flowing hinder but that the said motion of the Earth may be miraculous Now reassuming our Argument I apply and once again affirm that it hath been hitherto unknown how it might be that the Waters contained in our Mediterranean Straights should make those motions as we see it doth if so be the said Straight or containing Vessel were immoveable And that which makes the difficulty and rendreth this matter inextricable are the things which I am about to speak of and which are daily observed Therefore lend me your attention We are here in Venice where at this time the Waters are low the Sea calm the Air tranquil suppose it to be young flood and that in the term of five or six hours the water do rise ten hand breadths and more that rise is not made by the first water which was said to be rarefied but it is done by the accession of new Water Water of the same sort with the former of the same brackishness of the same density of the same weight Ships Simplicius float therein as in the former without drawing an hairs breadth more water a Barrel of this second doth not weigh one single grain more or less than such another quantity of the other and retaineth the same coldness without the least alteration And it is in a word Water newly and visibly entred by the Channels and Mouth of the Lio. Consider now how and from whence it came thither Are there happly hereabouts any Gulphs or Whirle-pools in the bottom of the Sea by which the Earth drinketh in and spueth out the Water breathing as it were a great and monstruous Whale But if this be so how comes it that the Water doth not flow in
is ceased but by vertue of its own gravity and natural inclination to level and grow even it shall speedily return backwards of its own accord and as being grave and fluid shall not only move towards Aequilibrium but being impelled by its own impetus shall go beyond it rising in the part where before it was lowest nor shall it stay here but returning backwards anew with more reiterated reciprocations of its undulations it shall give us to know that it will not from a velocity of motion once conceived reduce it self in an instant to the privation thereof and to the state of rest but will successively by decreasing a little and a little reduce it self unto the same just in the same manner as we see a weight hanging at a cord after it hath been once removed from its state of rest that is from its perpendicularity of its own accord to return thither and settle it self but not till such time as it shall have often past to one side and to the other with its reciprocall vibrations The second accident to be observed is that the before-declared reciprocations of motion come to be made and repeated with greater or lesser frequency that is under shorter or longer times according to the different lengths of the Vessels containing the waters so that in the shorter spaces the reciprocations are more frequent and in the longer more rare just as in the former example of pendent bodies the vibrations of those that are hanged to longer cords are seen to be lesse frequent than those of them that hang at shorter strings And here for a third observation it is to be noted that not onely the greater or lesser length of the Vessel is a cause that the water maketh its reciprocations under different times but the greater or lesser profundity worketh the same effect And it happeneth that of waters contained in receptacles of equall length but of unequal depth that which shall be the deepest maketh its undulations under shorter times and the reciprocations of the shallower waters are lesse frequent Fourthly there are two effects worthy to be noted and diligently observed which the water worketh in those its vibrations the one is its rising and falling alternately towards the one and other extremity the other is its moving and running to so speak Horizontally forwards and backwards Which two different motions differently reside in divers parts of the Water for its extream parts are those which most eminently rise and fall those in the middle never absolutely moving upwards and downwards of the rest successively those that are neerest to the extreams rise and fall proportionally more than the remote but on the contrary touching the other progressive motion forwards and backwards the middle parts move notably going and returning and the waters that are in the extream parts gain no ground at all save onely in case that in their rising they overflow their banks and break forth of their first channel and receptacle but where there is the obstacle of banks to keep them in they onely rise and fall which yet hindereth not the waters in the middle from fluctuating to and again which likewise the other parts do in proportion undulating more or lesse according as they are neerer or more remote from the middle The fifth particular accident ought the more attentively to be considered in that it is impossible to represent the effect thereof by an experiment or example and the accident is this In the vessels by us framed with art and moved as the above-named Bark one while more and another while lesse swiftly the acceleration and retardation is imparted in the same manner to all the vessel and to every part of it so that whilst v. g. the Bark forbeareth to move the parts precedent retard no more than the subsequent but all equally partake of the same retardment and the self-same holds true of the acceleration namely that conferring on the Bark a new cause of greater velocity the Prow and Poop both accelerate in one and the same manner But in huge great vessels such as are the very long bottomes of Seas albeit they also are no other than certain cavities made in the solidity of the Terrestrial Globe it alwayes admirably happeneth that their extreams do not unitedly equall and at the same moments of time increase and diminish their motion but it happeneth that when one of its extreames hath by vertue of the commixtion of the two Motions Diurnal and Annual greatly retarded its velocity the other extream is animated with an extream swift motion Which for the better understanding of it we will explain reassuming a Scheme like to the former in which if we do but suppose a tract of Sea to be long v. g. a fourth part as is the arch B C in Fig. 2. because the parts B are as hath been already declared very swift in motion by reason of the union of the two motions diurnal and annual towards one and the same way but the part C at the same time is retarded in its motion as being deprived of the progression dependant on the diurnal motion If we suppose I say a tract of Sea as long as the arch B C we have already seen that its extreams shall move in the same time with great inequality And extreamly different would the velocities of a tract of Sea be that is in length a semicircle and placed in the position B C D in regard that the extream B would be in a most accelerate motion and the other D in a most slow one and the intermediate parts towards C would be in a moderate motion And according as the said tracts of Sea shall be shorter they shall lesse participate of this extravagant accident of being in some hours of the day with their parts diversly affected by velocity and tardity of motion So that if as in the first case we see by experience that the acceleration and retardation though equally imparted to all the parts of the conteining Vessel is the cause that the water contained fluctuates too and again what may we think would happen in a Vessel so admirably disposed that retardation and acceleration of motion is very unequally contributed to its parts Certainly we must needs grant that greater and more wonderful causes of the commotions in the Water ought to be looked for And though it may seem impossible to some that in artificial Machines and Vessels we should be able to experiment the effects of such an accident yet neverthelesse it is not absolutely impossible to be done and I have by me the model of an Engine in which the effect of these admirable commixtions of motions may be particularly observed But as to what concerns our present purpose that which you may have hitherto comprehended with your imagination may suffice SAGR. I for my own particular very well conceive that this admirable accident ought necessarily to evene in the Straights of Seas and especially
in those that distend themselves for a great length from VVest to East namely according to the course of the motions of the Terrestrial Globe and as it is in a certain manner unthought of and without a president among the motions possible to be made by us so it is not hard for me to believe that effects may be derived from the same which are not to be imitated by our artificial experiments SALV These things being declared it is time that we proceed to examine the particular accidents which together with their diversities are observed by experience in the ebbing and flowing of the waters And first we need not think it hard to guesse whence it happeneth that in Lakes Pooles and also in the lesser Seas there is no notable flux and reflux the which hath two very solid reasons The one is that by reason of the shortnesse of the Vessel in its acquiring in several hours of the day several degrees of velocity they are with very little difference acquired by all its parts for as well the precedent as the subsequent that is to say both the Eastern and VVestern parts do accelerate and retard almost in the same manner and withal making that alteration by little and little and not by giving the motion of the conteining Vessel a sudden check and retardment or a sudden and great impulse or acceleration both it and all its parts come to be gently and equally impressed with the same degrees of velocity from which uniformity it followeth that also the conteined water with but small resistance and opposition receiveth the same impressions and by consequence doth give but very obscure signes of its rising or falling or of its running towards one part or another The which effect is likewise manifestly to be seen in the little artificial Vessels wherein the contained water doth receive the self same impressions of velocity when ever the acceleration and retardation is made by gentle and uniform proportion But in the Straights and Bays that for a great length distend themselves from East to West the acceleration and retardation is more notable and more uneven for that one of its extreams shall be much retarded in motion and the other shall at the same time move very swiftly The reciprocal libration or levelling of the water proceeding from the impetus that it had conceived from the motion of its container The which libration as hath been noted hath its undulations very frequent in small Vessels from whence ensues that though there do reside in the Terrestrial motions the cause of conferring on the waters a motion onely from twelve hours to twelve hours for that the motion of the conteining Vessels do extreamly accelerate and extreamly retard but once every day and no more yet neverthelesse this same second cause depending on the gravity of the water which striveth to reduce it self to equilibration and that according to the shortnesse of the Vessel hath its reciprocations of one two three or more hours this intermixing with the first which also it self in small Vessels is very little it becommeth upon the whole altogether insensible For the primary cause which hath the periods of twelve hours having not made and end of imprinting the precedent commotion it is overtaken and opposed by the other second dependant on the waters own weight which according to the brevity and profundity of the Vessel hath the time of its undulations of one two three four or more hours and this contending with the other former one disturbeth and removeth it not permitting it to come to the height no nor to the half of its motion and by this contestation the evidence of the ebbing and flowing is wholly annihilated or at least very much obscured I passe by the continual alteration of the air which disquieting the water permits us not to come to a certainty whether any though but small encrease or abatement of half an inch or losse do reside in the Straights or receptacles of water not above a degree or two in length I come in the second place to resolve the question why there not residing any vertue in the primary principle of commoving the waters save onely every twelve hours that is to say once by the greatest velocity and once by the greatest tardity of motion the ebbings and flowings should yet neverthelesse appear to be every six hours To which is answered that this determination cannot any wayes be taken from the primary cause onely but there is a necessity of introducing the secondary causes as namely the greater or lesse length of the Vessels and the greater or lesse depth of the waters in them conteined Which causes although they have not any operation in the motions of the waters those operations belonging to the sole primary cause without which no ebbing or flowing would happen yet neverthelesse they have a principal share in determining the times or periods of the reciprocations and herein their influence is so powerful that the primary cause must of force give way unto them The period of six hours therefore is no more proper or natural than those of other intervals of times though indeed its the most observed as agreeing with our Mediterrane which was the onely Sea that for many Ages was navigated though neither is that period observed in all its parts for that in some more angust places such as are the Hellespont and the Aegean Sea the periods are much shorter and also very divers amongst themselves for which diversities and their causes incomprehensible to Aristotle some say that after he had a long time observed it upon some cliffes of Negropont being brought to desperation he threw himself into the adjoyning Euripus and voluntarily drowned himself In the third place we have the reason ready at hand whence it commeth to passe that some Seas although very long as is the Red Sea are almost altogether exempt from Tides which happeneth because their length extendeth not from East to West but rather transversly from the Southeast to the Northwest but the motions of the Earth going from West to East the impulses of the water by that means alwayes happen to fall in the Meridians and do not move from parallel to parallel insomuch that in the Seas that extend themselves athwart towards the Poles and that the contrary way are narrow there is no cause of ebbing and flowing save onely by the participation of another Sea wherewith it hath communication that is subject to great commotions In the fourth place we shall very easily find out the reason why the fluxes and refluxes are greatest as to the waters rising and falling in the utmost extremities of Gulphs and least in the intermediate parts as daily experience sheweth here in Venice lying in the farther end of the Adriatick Sea where that difference commonly amounts to five or six feet but in the places of the Mediterrane far distant from the extreams that mutation is very small as in
for a long tract or distance from West to East that is according to the course of the fluxes and refluxes therefore in this the agitations are very great and would be much more violent between Hercules Pillars in case the Straight of Gibraltar did open lesse and those of the Straight of Magellanes are reported to be extraordinary violent This is what for the present cometh into my mind to say unto you about the causes of this first period diurnal of the Tide and its various accidents touching which if you have any thing to offer you may let us hear it that so we may afterwards proceed to the other two periods monethly and annual SIMP In my opinion it cannot be denied but that your discourse carrieth with it much of probability arguing as we say ex suppositione namely granting that the Earth moveth with the two motions assigned it by Copernicus but if that motion be disproved all that you have said is vain and insignificant and for the disproval of that Hypothesis it is very manifestly hinted by your Discourse it self You with the supposition of the two Terrestrial motions give a reason of the ebbing and flowing and then again arguing circularly from the ebbing and flowing draw the reason and confirmation of those very motions and so proceeding to a more specious Discourse you say that the Water as being a fluid body and not tenaciously annexed to the Earth is not constrained punctually to obey every of its motions from which you afterwards infer its ebbing and flowing Now I according to your own method argue the quite contrary and say the Air is much more tenuous and fluid than the Water and lesse annexed to the Earths superficies to which the Water if it be for nothing else yet by reason of its gravity that presseth down upon the same more than the light Air adhereth therefore the Air is much obliged to follow the motions of the Earth and therefore were it so that the Earth did move in that manner we the inhabitants of it and carried round with like velocity by it ought perpetually to feel a Winde from the East that beateth upon us with intolerable force And that so it ought to fall out quotidian experience assureth us for if with onely riding post at the speed of eight or ten miles an hour in the tranquil Air the incountering of it with our face seemeth to us a Winde that doth not lightly blow upon us what should we expect from our rapid course of 800. or a thousand miles an hour against the Air that is free from that motion And yet notwithstanding we cannot perceive any thing of that nature SALV To this objection that hath much of likelihood in it I reply that its true the Air is of greater tenuity and levity and by reason of its levity lesse adherent to the Earth than Water so much more grave and bulky but yet the consequence is false that you infer from these qualities namely that upon account of that its levity tenuity and lesse adherence to the Earth it should be more exempt than the Water from following the Terrestrial Motions so as that to us who absolutely pertake of of them the said exemption should be sensible and manifest nay it happeneth quite contrary for if you well remember the cause of the ebbing and flowing of the Water assigned by us consisteth in the Waters not following the unevennesse of the motion of its Vessel but retaining the impetus conceived before without diminishing or increasing it according to the precise rate of its diminishing or increasing in its Vessel Because therefore that in the conservation and retention of the impetus before conceived the disobedience to a new augmentation or diminution of motion consisteth that moveable that shall be most apt for such a retention shall be also most commodious to demonstrate the effect that followeth in consequence of that retention Now how much the Water is disposed to maintain such a conceived agitation though the causes cease that impress the same the experience of the Seas extreamly disturbed by impetuous Winds sheweth us the Billows of which though the Air be grown calm and the Wind laid for a long time after continue in motion As the Sacred Poet pleasantly sings Qual l'alto Egeo c. And that long continuing rough after a storm dependeth on the gravity of the water For as I have elsewhere said light bodies are much easier to be moved than the more grave but yet are so much the less apt to conserve the motion imparted when once the moving cause ceaseth Whence it comes that the Aire as being of it self very light and thin is easily mov'd by any very small force yet it is withall very unable to hold on its motion the Mover once ceasing Therefore as to the Aire which environs the Terrestrial Globe I would fay that by reason of its adherence it is no lesse carried about therewith then the Water and especially that part which is contained in its vessels which vessels are the valleys enclosed with Mountains And we may with much more reason affirm that this same part of the Air is carried round and born forwards by the rugged parts of the Earth than that the higher is whirl'd about by the motion of the Heavens as ye Peripateticks maintain What hath been hitherto spoken seems to me a sufficient answer to the allegation of Simplitius yet nevertheless with a new instance and solution founded upon an admirable experiment I will superabundantly satisfie him and confirm to Sagredus the mobility of the Earth I have told you that the Air and in particular that part of it which ascendeth not above the tops of the highest Mountains is carried round by the uneven parts of the Earths surface from whence it should seem that it must of consequence come to passe that in case the superficies of the Earth were not uneven but smooth and plain no cause would remain for drawing the Air along with it or at least for revolving it with so much uniformity Now the surface of this our Globe is not all craggy and rugged but there are exceeding great tracts very even to wit the surfaces of very vast Seas which being also far remote from the continuate ledges of Mountains which environ it seem to have no faculty of carrying the super-ambient Air along therewith and not carrying it about we may perceive what will of consequence ensue in those places SIMP I was about to propose the very same difficulty which I think is of great validity SALV You say very well Simplicius for from the not finding in the Air that which of consequence would follow did this our Globe move round you argue its immoveablenesse But in case that this which you think ought of necessary consequence to be found be indeed by experience proved to be so will you accept it for a sufficient testimony and an argument for the mobility of
the said Globe SIMP In this case it is not requisite to argue with me alone for if it should so fall out and that I could not comprehend the cause thereof yet haply it might be known by others SALV So that by playing with you a man shall never get but be alwayes on the losing hand and therefore it would be better to give over Nevertheless that we may not cheat our third man we will play on We said even now and with some addition we reitterate it that the Ayr as if it were a thin and fluid body and not solidly conjoyned with the Earth seem'd not to be necessitated to obey its motion unlesse so far as the cragginess of the terrestrial superficies transports and carries with it a part thereof contigious thereunto which doth not by any great space exceed the greatest altitude of Mountains the which portion of Air ought to be so much less repugnant to the terrestrial conversion by how much it is repleat with vapours fumes and exhalations matters all participating of terrene qualities and consequently apt of their own nature to the same motions But where there are wanting the causes of motion that is where the surface of the Globe hath great levels and where there is less mixture of the terrene vapours there the cause whereby the ambient Air is constrained to give entire obedience to the terrestrial conversion will cease in part so that in such places whilst the Earth revolveth towards the East there will be continually a wind perceived which will beat upon us blowing from the East towards the West and such gales will be the more sensible where the revolution of the Globe is most swift which will be in places more remote from the Poles and approaching to the greatest Circle of the diurnal conversion But now de facto experience much confirmeth this Phylosophical argumentation for in the spatious Seas and in their parts most remote from Land and situate under the Torrid Zone that is bounded by the Tropicks where there are none of those same terrestrial evaporations we finde a perpetual gale move from the East with so constant a blast that ships by favour thereof sail prosperously to the West-India's And from the same coasting along the Mexican shore they with the same felicity pass the Pacifick Ocean towards the India's which to us are East but to them are West Whereas on the contrary the Course from thence towards the East is difficult and uncertain and not to be made by the same Rhumb but must vere more to Land-ward to recover other Winds which we may call accidentary and tumultuary produced from other Principles as those that inhabit the continent find by experience Of which productions of Winds the Causes are many and different which shall not at this time be mentioned And these accidentary Winds are those which blow indifferently from all parts of the Earth and make rough the Seas remote from the Equinoctial and environed by the rugged Surface of the Earth which is as much as to say environ'd with those perturbations of Air that confound that primary Gale The which in case these accidental impediments were removed would be continually felt and especially upon the Sea Now see how the effect of the Water and Air seem wonderfully to accord with the Celestial observations to confirm the mobility of our Terrestrial Globe SAGR. I also for a final close will relate to you one particular which as I believe is unknown unto you and which likewise may serve to confirm the same conclusion You Salviatus alledged That Accident which Sailers meet with between the Tropicks I mean that perpetual Gale of Winde that beats upon them from the East of which I have an account from those that have many times made the Voyage And moreover which is very observable I understand that the Mariners do not call it a Wind but by another name which I do not now remember taken haply from its so fixed and constant Tenor which when they have met with they tie up their shrouds and other cordage belonging to the Sails and without any more need of touching them though they be in a sleep they can continue their course Now this constant Trade-wind was known to be such by its continual blowing without interruptions for if it were interrupted by other Windes it would not have been acknowledged for a singular Effect and different from the rest from which I will infer That it may be that also our Mediterranean Sea doth partake of the like accident but it is not observed as being frequently altered by the confluence of other windes And this I say not without good grounds yea upon very probable conjectures whch came unto my knowledge from that which tendred it self to my notice on occasion of the voyage that I made into Syria going Consul for this Nation to Aleppo and this it is That keeping a particular account and memorial of the dayes of the departure and arrival of the Ships in the Ports of Alexandria of Alexandretta and this of Venice in comparing sundry of them which I did for my curiosity I found that in exactness of account the returns hither that is the voiages from East to West along the Mediterrane are made in less time then the contrary courses by 25. in the Hundred So that we see that one with another the Eastern windes are stronger then the Western SALV I am very glad I know this particular which doth not a little make for the confirmation of the Earths mobility And although it may be alledged That all the Water of the Mediterrane runs perpetually towards the Straits-mouth as being to disimbogue into the Ocean the waters of as many Rivers as do discharge themselves into the same I do not think that that current can be so great as to be able of it self alone to make so notable a difference which is also manifest by observing that the water in the Pharo of Sicily runneth back again no less towards the East than it runneth forwards towards the West SAGR. I that have not as Simplicius an inclination to satisfie any one besides my self am satisfied with what hath been said as to this first particular Therefore Salviatus when you think it sit to proceed forward I am prepared to hear you SALV I shall do as you command me but yet I would fain hear the opinion also of Simplicius from whose judgement I can argue how much I may promise to my self touching these discourses from the Peripatetick Schools if ever they should come to their ears SIMP I desire not that my opinion should serve or stand for a measure whereby you should judge of others thoughts for as I have often said I am inconsiderable in these kinde of studies and such things may come into the mindes of those that are entered into the deepest passages of Philosophy as I could never think of as having according to the Proverb
of the ebbing and flowing you must finde and give us some reason why it doth in the self same place run one while one way and another while another Effects that being contrary irregular can never be deduced from any uniform and constant Cause And this Argument that overthrows the Hypothesis of the motion contributed to the Sea from the Heavens diurnal motion doth also confute that Position of those who would admit the sole diurnal motion of the Earth and believe that they are able with that alone to give a reason of the Flux and Reflux Of which effect since it is irregular the cause must of necessity be irregular and alterable SIMP I have nothing to reply neither of my own by reason of the weakness of my understanding nor of that of others for that the Opinion is so new But I could believe that if it were spread amongst the Schools there would not want Phylosophers able to oppose it SAGR. Expect such an occasion and we in the mean time if it seem good to Salviatus will proceed forward SALV All that which hath been said hitherto pertaineth to the diurnal period of the ebbing and flowing of which we have in the first place demonstrated in general the primary and universal Cause without which no such effect would follow Afterwâ—â—ds passing to the particular Accidents various and in a certain sort irregular that are observed therein We have handled the secondary and concommitant Causes upon which they depend Now follow the two other Periods Monethly and Annual which do not bring with them new and different Accidents other than those already considered in the diurnal Period but they operate on the same Accidents by rendring them greater and lesser in several parts of the Lunar Moneth and in several times of the Solar Year as if that the Moon and Sun did each conceive it self apart in operating and producing of those Effects a thing that totally clasheth with my understanding which seeing how that this of Seas is a local and sensible motion made in an immense mass of Water it cannot be brought to subscribe to Lights to temperate Heats to predominacies by occult Qualities and to such like vain Imaginations that are so far from being or being possible to be Causes of the Tide that on the contrary the Tide is the cause of them that is of bringing them into the brains more apt for loquacity and ostentation than for the speculation and discovering of the more abstruse secrets of Nature which kind of people before they can be brought to pronounce that wise ingenious and modest sentence I know it not suffer to escape from their mouths and pens all manner of extravagancies And the onely observing that the same Moon and the same Sun operate not with their light with their motion with great heat or with temperate on the lesser reeeptaclâ—s of Water but that to effect their flowing by heat they must be reduced to little lesse than boiling and in short we not being able artificially to imitate any way the motions of the Tide save only by the motion of the Vessel ought it not to satisfie every one that all the other things alledged as causes of those effects are vaine fancies and altogether estranged from the Truth I say therefore that if it be true that of one effect there is but one sole primary cause and that between the cause and effect there is a firm and constant connection it is necessary that whensoever there is seen a firm and constant alteration in the effect there be a firm and constant alteration in the cause And because the alterations that happen in the ebbing and flowing in several parts of the Year and Moneths have their periods firm and constant it is necessary to say that a regular alteration in those same times happeneth in the primary cause of the ebbings and flowings And as for the alteration that in those times happens in the ebbings and flowings consisteth onely in their greatness that is in the Waters rising and falling more or lesse and in running with greater or lesse impetus therefore it is necessary that that which is the primary cause of the ebbing and flowing doth in those same determinate times increase and diminish its force But we have already concluded upon the inequality and irregularity of the motion of the Vessels containing the Water to be the primary cause of the ebbings and flowings Therefore it is necessary that that irregularity from time to time correspondently grow more irregular that is grow greater and lesser Now it is requisite that we call to minde that the irregularity that is the different velocity of the motions of the Vessels to wit of the parts of the Terrestrial Superficies dependeth on their moving with a compound motion resulting from the commixtion of the two motions Annual and Diurnal proper to the whole Terrestrial Globe of which the Diurnal conversion by one while adding to and another while substracting from the Annual motion is that which produceth the irregularity in the compound motion so that in the additions and substractions that the Diurnal revolution maketh from the Annual motion consisteth the original cause of the irregular motion of the Vessels and consequently of the Ebbing and Flowing insomuch that if these additions and substractions should alwayes proceed in the same proportion in respect of the Annual motion the cause of the Ebbing and Flowing would indeed continue but yet so as that they would perpetually return in the self same manner But we are to finde out the cause of making the same Ebbings and Flowings in divers times greater and lesser Therefore we must if we will retain the identity of the cause find the alteration in these additions and substractions that make them more less potent in producing those effects which depend thereupon But I see not how that potency and impotence can be introduced unlesse by making the same additions and substractions one while greater and another while lesser so that the acceleration and the retardment of the compound motion may be made sometimes in greater and sometimes in lesser proportion SAGR. I feel my self very gently led as it were by the hand and though I finde no rubs in the way yet neverthelesse like a blind man I see not whether your Clue leadeth me nor can I imagine where such a Journey will end SALV Though there be a great difference between my slow pac't Philosophy and your more nimble Reason yet neverthelesse in this particular which we are now upon I do not much wonder if the apprehensivenesse of your wit be a little obscured by the dark and thick mist that hides the mark at which we aime and that which lesseneth my admiration is the remembrance of the many hours many dayes yea more many nights that I have consumed in this contemplation and of the many times that despairing to bring it to a period I have for an incouragement of my self
indeavoured to believe by the example of the unfortunate Orlando that that might not possibly be true which yet the testimony of so many credible men set before my eyes wonder not therefore if this once contrary to your custome you do not foresee what I intend and if you will needs admire I believe that the event as far as I can judge unexpected will make you cease your wonderment SAGR. I thank God that he did not permit that desperation of yours to end in the Exit that is fabled of the miserable Orlando nor in that which haply is no lesse fabulously related of Aristotle that so neither my self nor others should be deprived of the discovery of a thing as abstruse as it was desirable I beseech you therefore to satisfie my eager appetite as soon as you can SALV I am ready to serve you We were upon an inquiry in what manner the additions and substractions of the Terrestriall conversion from the Annual motion could be made one while in a greater and another while in a lesser proportion which diversity and no other thing could be assigned for the cause of the alterations Monethly and Annual that are seen in the greatnesse of the Ebbings and Flowings I will now consider how this proportion of the additions and substractions of the Diurnal Revolution and Annual motion may grow greater and lesser three several wayes One is by increasing and diminishing the velocity of the Annual motion retaining the additions and substractions made by the Diurnal conversion in the same greatnesse because the Annual motion being about three times greater that is more velocious than the Diurnal motion considered likewise in the Grand Circle if we increase it anew the additions and substractions of the Diurnal motion will occasion lesse alteration therein but on the other side making it more slow it will be altered in greater proportion by that same diurnal motion just as the adding or substracting four degrees of velocity from one that moveth with twenty degrees altereth his course lesse than those very four degrees would do added or substracted from one that should move onely with ten degrees The second way would be by making the additions and substractions greater and lesser retaining the annual motion in the same velocity which is as easie to be understood as it is manifest that a velocity v. gr of 20 degr is more altered by the addition or substraction of 10. deg than by the addition or substraction of 4. The third way would be in case these two were joyned together diminishing the annual motion increasing the diurnal additions and substractions Hitherto as you see it was no hard matter to attain but yet it proved to me very hard to find by what means this might be effected in Nature Yet in the end I finde that she doth admirably make use thereof and in wayes almost incredible I mean admirable and incredible to us but not to her who worketh even those very things which to our capacity are of infinite wonder with extraordinary facility and simplicity and that which it is hard for us to understand is easie for her to effect Now to proceed having shewn that the proportion between the additions and substractions of the Diurnal conversion and Annual motion may be made greater and lesser two wayes and I say two because the third is comprized in the two first I adde that Nature maketh use of them both and farthermore I subjoyn that if she did make use but of one alone it would be necessary to take away one of the two Periodical alterations That of the Monethly Period would cease if the annual motion should not alter And in case the additions and substractions of the diurnal revolution should continually be equal the alterations of the annual Period would fail SAGR. It seems then that the Monethly alteration of ebbings and flowings dependeth on the alteration of the annual motion of the Earth And the annual alteration of those ebbings and flowings do it seems depend on the additions and substractions of the diurnal conversion And here now I finde my self worse puzzled than before and more out of hope of being able to comprehend how this intricacy may be which is more inextricable in my judgment than the Gordian knot And I envy Simplicius from whose silence I argue that he doth apprehend the whole businesse and is acquit of that confusion which greatly puzzleth my brains SIMP I believe verily Sagredus that you are put to a a stand and I believe that I know also the cause of your confusion which if I mistake not riseth from your understanding part of those particulars but even now alledged by Salviatus and but a part It is true likewise that I find my self free from the like confusion but not for that cause as you think to wit because I apprehend the whole nay it happens upon the quite contrary account namely from my not comprehending any thing and confusion is in the plurality of things and not in nothing SAGR. You see Salviatus how a few checks given to Simplicius in the dayes preceding have rendered him gentle and brought him from the capriol to the amble But I beseech you without farther delay put us both out of suspence SALV I will endeavour it to the utmost of my harsh way of expressing my self the obtusenesse of which the acutenesse of your wit shall supply The accidents of which we are to enquire the causes are two The first respecteth the varieties that happen in the ebbings and flowings in the Monethly Period and the othr relateth to the Annual We will first speak of the Monethly and then treat of the Annual and it is convenient that we resolve them all according to the Fundamentals and Hypothesis already laid down without introducing any novelty either in Astronomy or in the Universe in favour of the ebbings and flowings therefore let us demonstrate that of all the several accidents in them observed the causes reside in the things already known and received for true and undoubted I say therefore that it is a truly natural yea necessary thing that one and the same moveable made to move round by the same moving virtue in a longer time do make its course by a greater circle rather than by a lesser and this is a truth received by all and confirmed by all experiments of which we will produce a few In the wheel-clocks and particularly in the great ones to moderate the time the Artificers that make them accomodate a certain voluble staffe horozontally and at each end of it they fasten two Weights of Lead and when the time goeth too slow by the onely removing those Leads a little nearer to the centre of the staffe they render its vibrations more frequent and on the contrary to retard it it is but drawing those Weights more towards the ends for so the vibrations are made more seldome and consequently the intervals of the hours
filched from the Ancients and somewhat altered 99 Aristotle his Arguments for the Earths Quiescence and Immobility 107 Aristotle were he alive would either refute his Adversaries Arguments or else would alter his Opinion 113 Aristotles first Argument against the Earths Motion is defective in two things 121 The Paralogisme of Aristotle and Ptolomy in supposing that for known which is in question 121 Aristotle admitteth that the Fire moveth directly upwards by Nature and round about by Participation 122 Aristotle and Ptolomy seem to confute the Earths Mobility against those who think that it having along time stood still began to move in the time of Pythagoras 168 Aristotle his errour in affirming falling Grave Bodies to move according to the proportion of their gravities 199 Aristotle his Demonstrations to prove the Earth is finite are all nullified by denying it to be moveable 294 Aristotle maketh that Point to be the Centre of the Universe about which all the Celestial Spheres do revolve 294 A question is put if Arist. were forced to receive one of two Propositions that make against his Doctrine which he would admit 294 Aristotle his Argument against the Ancients who held that the Earth was a Planet 344 Aristotle taxeth Plato of being over-studious of Geometry 361 Aristotle hâ—ldeth those Effects to be miraculous of which the Causes are unknown 384 ASTRONOMERS Astronomers confuted by Anti-Tycho 38 The principal Scope of Astronomers is to give a reason of Appearances and Phaenomena 308 Astronomers all agree that the greater Magnitudes of the Orbes is the cause of the tardity in their Conversions 331 Astronomers perhaps have not known what Appearances ought to follow upon the Annual Motion of the Earth 338 Astronomers having omitted to instance what alterations those are that may be derived from the Annual Motion of the Earth do thereby testifie that they never rightly understood the same 343 ASTRONOMICAL Astronomical Observations wrested by Anti-Tycho to his own purpose 39 Astronomical Instruments are very subject to errour 262 ASTRONOMY Astronomy restored by Copernicus upon the Suppositions of Ptolomy 308 Many things may remain as yet unobserved in Astronomy 415 AUCUPATORIAN An Aucupatorian Problem for shooting of Birds flying 157 AXIOME or Axiomes In the Axiome Frustra fit per plura c. the addition of aequae bene is super fluous 106 Three Axiomes that are supposed manifest 230 Certain Axiomes commonly admitted by all Philosophers 361 B BODY and Bodies Contraries that corrupt reside not in the same Body that corrupteth 30 GRAVE BODY If the Celestial Globe were perforated a Grave Body descending by that Bore would passe and ascend as far beyond the Centre as it did descend 203 The motion of Grave Bodies Vide Motion The Accelleration of Grave Bodies that descend naturally increaseth from moment to moment 205 We know no more who moveth Grave Bodies downwards than who moveth the Stars round nor know we any thing of these Courses more than the Names imposed on them by our selves 210 The great Masse of Grave Bodies being transferred out of their Place the seperated parts would follow that Masse 221 PENSILE BODY Every Pensile Body carried round in the Circumference of a Circle acquireth of it self a Motion in it self contrary to the same 362 CELESTIAL BODIES neither heavy nor light according to Aristotle 23 Celestial Bodies are Generable and Corruptible because they are Ingenerable and Incorruptible 29 Amongst Celest. Bodies there is no contrariety 29 Celestial Bodies touch but are not touched by the Elements 30 Rarity and Density in Celestial Bodies different from Rarity and Density in the Elements 30 Celestial Bodies designed to serve the Earth need no more but Motion and Light 45 Celestial Bodies want an interchangeable Operation on each other 46 Celestial Bodies alterable in their externe parts 46 Perfect Sphericity why ascribed to Celestial Bodies by Peripateticks 69 All Celestial Bodies have Gravity and Levity 493 ELEMENTARY BODIES Their propension to follow the Earth hath a limited Sphere of Activity 213 LIGHT BODIES easier to be moved than heavy but lesse apt to conserve the Motion 400 LUMINOUS BODIES Bodies naturally Luminous are different from those that are by nature Obscure 34 The reason why Luminous Bodies appear so much the more enlarged by how much they are lesser 304 Manifest Experience shews that the more Luminous Bodies do much more irradiate than the lesse Lucid. 306 SIMPLE BODYES have but one Simple Motion that agreeth with them 494 SPHERICAL BODIES In Spherical Bodies Deorsum is the Centre and Sursum the Cirference 479 BONES The ends of the Bones are rotund and why 232 BUONARRUOTTI Buonarruotti a Statuary of admirable ingenuity 86 C CANON A shameful Errour in the Argument taken from the Canon-Bullets falling from the Moons Concave 197 An exact Computation of the fall of the Canon-Bullet from the Moons Concave to the Centre of the Earth 198 CELESTIAL Celestial Substances that be Vnalterable and Elementary that be Alterable necessary in the opinion of Aristotle 2 CENTRE The Sun more probably in the Centre of the Vniverse than the Earth 22 Natural inclination of all the Globes of the World to go to their Centre 22 Grave Bodies may more rationally be affirmed to tend towards the Centre of the Earth than of the Vniverse 25 CHYMISTS Chymists interpret the Fables of Poets to be Secrets for making of Gold 93 CIRCLE and Circular It is not impossible with the Circumference of a small Circle few times revolved to measure and describe a line bigger than any great Circle whatsoever 222 The Circular Line perfect according to Aristotle and the Right imperfect and why 9 CLARAMONTIUS The Paralogisme of Claramontius 241 The Argument of Claramontius recoileth upon himself 245 The Method observed by Claramontius in consuting Astronomers and by Salviatus in refuting him 253 CLOUDS Clouds no lesse apt than the Moon to be illuminated by the Sun 73 CONCLUSION and Conclusions The certainty of the Conclusion helpeth by a resolutive Method to finde the Demonstration 37 The Book of Conclusioâ—s frequently mentioned was writ by Christopher Scheiner a Jesuit 195 323. CONTRARIES Contraries that corrupt reside not in the same Body that corrupteth 30 COPERNICAN Answers to the three first Objections against the Copernican System 303 The Copernican System difficul to be understood but easie to be effected 354 A plain Scheme representing the Copernican Systeme and its consequences 354 The proscribing of the Copernican Doctrine after so long a Tolleration and now that it is more than ever followed studied and confirmed would be an affront to Truth 444 The Copern System admirably agreeth with the Miracle of Joshuah in the Literal Sense 456 If Divines would admit of the Copernican System they might soon find out Expositions for all Scriptures that seem to make against it 459 The Copernican System rejected by many out of a devout respect to Scripture Authorities 461 The Copernican System more plainly asserted in Scripture than the Ptolomaick 469 COPERNICANS Copernicans are
Earth answered by Examples of the like Motions in other Celestial Bodies 236 A fourth Argument of Claramontius against the Copernican Hypothesis of the Earths Mobility 239 From the Earths obscurity and the splendor of the fixed Stars it is argued that it is moveable and they immoveable 239 A fifth Argument of Claramontius against the Copernican Hypothesis of the Earths Mobility 240 Another difference between the Earth and Celestial Bodies taken from Purity and impurity 240 It seems a Solecisme to affirme that the Earth is not in Heaven 241 Granting to the Earth the Annual it must of necessity also have the Diurnal Motion assigned to it 300 Discourses more than childish that serve to keep Fools in the Opinion of the Earths Stability 301 The Difficulties removed that arise from the Earths moving about the Sun not solitarily but in consort with the Moon 307 The Axis of the Earth continueth alwayes parallel to it self and describeth a Cylindraical Superficies inclining to the Orb. 344 The Orb of the Earth never inclineth but is immutably the same 345 The Earth approacheth or recedeth from the fixed Stars of the Ecliptick the quantity of the Grand Orb. 349 If in the fixed Stars one should discover any Mutation the Motion of the Earth would be undeniable 351 Necessary Propositions for the better conceiving of the Consequences of the Earths Motion 354 An admirable Accident depending on the not-inclining of the Earths Axis 358 Four several Motions assigned to the Earth 362 The third Motion ascribed to the Earth is rather a resting immoveable 363 An admirable interne vertue or faculty of the Earths Globe to behold alwayes the same part of Heaven 363 Nature as iâ— sport maketh the Ebbing and Flowing of the Sea to prove the Earths Mobility 379 All Terrene Effects indifferently confirm the Motion or Rest of the Earth except the Ebbing and Flowing of the Sea 380 The Cavities of the Earth cannot approach or recede from the Centre of the same 387 The Hypothesis of the Earths Mobility taken in favour of the Ebbing and Flowing opposed 399 The Answers to those Objections made against the Earths Motion 399 The Revolution of the Earth confirmed by a new Argument taken from the Aire 400 The vaporous parts of the Earth partake of its Motions 400 Another observation taken from the Ayr in confirmation of the motion of the Earth 402 A Reason of the continual Motion of the Air and Water may be given by making the Earth moveable rather then by making it immoveable 405 The Earths Mobility held by sundry great Philosophers amongst the Antients 437 468 The Fathers agree not in expounding the Texts of Scripture that are alledged against the Earths Mobility 450 The Earth Mobility defended by many amongst the Modern Writers 478 The Earth shall stand still after the Day of Judgement 480 The Earth is another Moon or Star 486 The Earths several Motions according to Copernicus 491 The Earth secundum totum is Immutable though not Immoveable 491 The Earths Natural Place 492 The Earths Centre keepeth her in her Natural Place 493 The Earth in what Sense it may absolutely be said to be in the lowest part of the World 496 EBBING and Ebbings The first general Conclusion of the impossibility of Ebbing and Flowing the Immobility of the Terrestrial Globe being granted 380 The Periods of Ebbings and Flowings Diurnal Monethly and Annual 381 Varieties that happen in the Diurnal Period of the Ebbings and Flowings 382 The Causes of Ebbings and Flowings alledged by a Modern Phylosopher 382 The Cause of the Ebbing and Flowing ascribed to the Moon by a certain Prelate 383 The Cause of the Ebbing c. referred by Hyeronimus Borrius and other Peripateticks to the temperate heat of the Moon 383 Answers to the Vanities alledged as Causes of the Ebbing and Flowing 383 It s proved impossible that there should naturally be any Ebbing and Flowing the Earth being immoveable 386 The most potent and primary Cause of the Ebbing and Flowing 390 Sundry accidents that happen in the Ebbings and Flowings 391 Reasons renewed of the particular Accidents observed in the Ebbings and Flowings 393 Second Causes why in several Seas and Lakes there are no Ebbings and Flowings 394 The Reason why the Ebbings and Flowings for the most part are every Six Hours 395 The Cause why some Seas though very long suffer no Ebbing and Flowing 395 Ebbings and Flowings why greatest in the Extremities of Gulphs and least in the middle parts 396 A Discussion of some more Abstruce Accidents observed in the Ebbing and Flowing 396 The Ebbing and Flowing may depend on the Diurnal Motion of Heaven 404 The Ebbing and Flowing cannot depend on the Motion of Heaven 405 The Causes of the Periods of the Ebbings and Flowings Monethly and Annual at large assigned 407 The Monethly and Annual alterations of the Ebbings and Flowings can depend on nothing save on the alteration of the Additions and Subtractions of the Diurnal Period from the Annual 408 Three wayes of altering the proportion of the Additions of the Diurnal Revolution to the Annual Motion of the Ebbing and Flowing 409 Ebbings and Flowings are petty things in comparison of the vastnesse of the Seas and the Velocity of the Motion of the Terrestrial Globe 417 EFFECT and Effects Of a new Effect its necessary that the Cause be likewise new 370 The Knowledge of the Effects contribute to the investigation of the Causes 380 True and Natural Effects follow without difficulty 387 Alterations in the Effects argue alteration in the Cause 407 ELEMENTS and their Motions Vide MOTION ENCYCLOPEDIA Subtilties sufficiently insipid ironically spoken and taken from a certain Encyclopedia 153 EXPERIMENTS Sensible Experiments are to be preferred before Humane Argumentations 21 33 42. It is good to be very cautious in admitting Experiments for true to those that never tryed them 162 Experiments and Arguments against the Earths Motion seem so far concluding as they lye under Equivokes 162 The Authority of Sensible Experiments and necessary Demonstrations in deciding of Physical Controversies 436 EYE The Circle of the Pupil of the Eye contracteth and enlargeth 329 How to finde the distance of the Rays Concourse from the Pupil of the Eye 329 F FAITH Faith more infallible than either Sense or Reason 475 FIRE Fire moveth directly upwards by Nature and round about by Participation according to Aristotle 122 It is improbable that the Element of Fire should be carried round by the Concave of the Moon 405 FIGURE and Figures Figure is not the Cause of Incorruptibility but of Longer Duration 66 The perfection of Figure appeareth in Corruptible Bodies but not in the Eternal 69 If the Spherical Figure conferred Eternity all things would be Eternal 69 It is more difficult to finde Figures that touch in a part of their Surface then in one sole point 185 The Circular Figure placed amongst the Postulata of Mathematicians 186 Irregular Figures and Formes difficult to be introduced 187 Superficial figures increase in proportion
inveigh and of whom in particular S. Hierom writeth This Scilicet the Sacred Scripture the talking old woman the doting old man the talkative Sophister all venture upon lacerate teach and that before they have learnt it Others induced by Pride diving into hard words Philosophate amongst Women touching the Holy Scriptures Others Oh shameful Learn of Women what they teach to Men and as if this were nothing in a certain facility of words I may say of confidence expound to others what they understand not themselves I forbear to speak of those of my own Profession who if after Humane Learning they chance to attain to the Holy Scriptures and tickle the ears of the people with affected and Studied expressions they affirm that all they say is to be entertained as the Law of God and not stooping to learn what the Prophets and Apostles held they force incongruous testimonies to their own Sense As if it were the genuine and not corrupt way of teaching to deprave Sentences and Wrest the Scripture according to their own singular and contradictory humour I will not rank among these same secular Writers any Theologists whom I repute to be men of profound Learning and sober Manners and therefore hold them in great esteem and veneration Yet I cannot deny but that I have a certain scruple in my mind and consequently am desirous to have it removed whilst I hear that they pretend to a power of constraining others by Authority of the Scriptures to follow that opinion in Natural Disputations which they think most agreeth with the Texts of that Holding withall that they are not bound to answer the Reasons and Experiments on the contrary In Explication and Confirmation of which their judgement they say That Theologie being the Queen of all the Sciences she ought not upon any account to stoop to accomodate her self to the Positions of the rest less worthy and inferior to her But that they ought to refer themselves to her as to their Supream Emperess and change and alter their Conclusions according to Theological Statutes and Decrees And they further add That if in the inferior Science there should be any Conclusion certain by vertue of Demonstrations or experiments to which there is found in Scripture another Conclusion repugnant the very Professors of that Science ought of themselves to resolve their Demonstrations and discover the falacies of their own Experiments without repairing to Theologers and Textuaries it not suiting as hath been said with the dignity of Theologie to stoop to the investigation of the falacies of the inferior Sciences But it sufficeth her to determine the truth of the Conclusion with her absolute Authority and by her infallibility And then the Natural Conclusions in which they say that we ought to bide by the meer Authority of the Scripture without glossing or expounding it to Senses different from the Words they affirm to be Those of which the Scripture speaketh alwaies in the same manner and the Holy Fathers all receive and expound to the same Sense Now as to these Determinations I have had occasion to consider some particulars which I will purpose for that I was made cautious thereof by those who understand more than I in these businesses and to whose judgements I alwaies submit my self And first I could say that there might possibly a certain kinde of equivocation interpose in that they do not distinguish the preheminences whereby Sacred Theologie meriteth the Title of Queen For it might be called so either because that that which is taught by all the other Sciences is found to be comprized and demonstrated in it but with more excellent means and with more sublime Learning in like manner as for example The Rules of measuring of Land of Accountantship are much more excellently contained in the Arithmatick and Geometry of Euclid than in the Practises of Surveyours and Accomptants Or because the Subject about which Theologie is conversant excelleth in Dignity all the other Subjects that are the Matters of other Sciences As also because its Documents are divulged by nobler waies That the Title and Authority of Queen belongeth to Theologie in the first Sense I think that no Theologers will affirm that have but any in-sight into the other Sciences of which there are none as I believe that will say that Geometry Astronomy Musick and Medicine are much more excellently and exactly contained in the Sacred Volumes than in the Books of Archimedes in Ptolomy in Boetius and in Galen Therefore it is probable that the Regal Preheminence is given her upon the second account namely By reason of the Subject and the admirable communicating of the Divine Revelations in those Conclusions which by other means could not be conceived by men and which chiefly concern the acquist of eternal Beatitude Now if Theologie being conversant about the loftiest Divine Contemplation and residing for Dignity in the Regal Throne of the Sciences whereby she becometh of highest Authority descendeth not to the more mean and humble Speculations of the inferior Sciences Nay as hath been declared above hath no regard to them as not concerning Beatitude the Professors thereof ought not to arrogate to themselves the Authority to determin of Controversies in those Professions which have been neither practised nor studied by them For this would be as if an Absolute Prince knowing that he might freely command and cause himself to be obeyed should being neither Phisitian nor Architect undertake to administer Medicines and erect Buildings after his own fashion to the great endangering af the lives of the poor Patients and to the manifest destruction of the Edifices Again to command the very Professors of Astronomy that they of themselves see to the confuting of their own Observations and Demonstrations as those that can be no other but Falacies and Sophismes is to enjoyn a thing beyond all possibility of doing For it is not onely to command them that they do not see that which they see and that they do not understand that which they understand but that in seeking they finde the contrary of that which they happen to meet with Therefore before that this is to be done it would be necessary that they were shewed the way how to make the Powers of the Soul to command one another and the inferior the Superior so that the imagination and will might and should believe contrary to what the Intellect understands I still mean in Propositions purely Natural and which are not de Fide and not in the Supernatural which are de Fide I would entreat these Wise and Prudent Fathers that they would withal diligence consider the difference that is between Opinable and Demonstrative Doctrines To the end that well weighing in their minds with what force Necessary Illations oblige they might the better ascertain themselves that it is not in the Power of the Professors of Demonstrative Sciences to change their Opinions at pleasure and apply themselves one while to one side and another
prefer them before those of other men and to believe that better and more agreeable to the intention of the Sacred Volumes cannot be produced Supposing therefore in the first place that in the Miracle of Joshuah the whole Systeme of the Celestial Revolutions stood still according to the judgement of the afore-named Authors And this is the rather to be admitted to the end that by the staying of one alone all the Constitutions might not be confounded and a great disorder needlesly introduced in the whole course of Nature I come in the second place to consider how the Solar Body although stable in one constant place doth nevertheless revolve in it self making an entire Conversion in the space of a Month or thereabouts as I conceive I have solidly demonstrated in my Letters Delle Machie Solari Which motion we sensibly see to be in the upper part of its Globe inclined towards the South and thence towards the lower part to encline towards the North just in the same manner as all the other Orbs of the Planets do Thirdly If we respect the Nobility of the Sun and his being the Fountain of Light by which as I necessarily demonstrate not onely the Moon and Earth but all the other Planets all in the same manner dark of themselves become illuminated I conceive that it will be no unlogicall Illation to say That it as the Grand Minister of Nature and in a certain sense the Soul and Heart of the World infuseth into the other Bodies which environ it not onely Light but Motion also by revolving in it self So that in the same manner that the motion of the Heart of an Animal ceasing all the other motions of its Members would cease so the Conversion of the Sun ceasing 〈◊〉 Conversions of all the Planets would stand still And though I could produce the testimonies of many grave Writers to prove the admirable power and influence of the Sun I will content my self with one sole place of Holy Dionisius Areopagita in his Book de Divinis Nominibus who thus writes of the Sun His Light gathereth and converts all things to himself which are seen moved illustrated wax hot and in a word those things which are preserved by his splendor Wherefore the Sun is called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 for that he collecteth and gathereth together all things dispersed And a little after of the Sun again he adds If this Sun which we see as touching the Essences and Qualities of those things which fall vvithin our Sense being very many and different yet if he vvho is one and equally bestovves his Light doth renew nourish defend perfect divide conjoyn cherish make fruitfull encrease change fix produce move and fashion all living creatures And every thing in this Vniverse at this Pleasure is partaker of one and the same Sun and the causes of many things which participate of him are equally auticipated in him Certainly by greater reason c. The Sun therefore being the Fountain of Light and Principle of Motion God intending that at the Command of Joshua all the World 's Systeme should continue many hours in the same state it sufficeth to make the Sun stand still upon whose stay all the other Conversions ceasing the Earth the Moon the Sun did abide in the same Constitution as before as likewise all the other Planets Nor in all that time did the Day decline towards Night but it was miraculously prolonged And in this manner upon the standing still of the Sun without altering or in the least disturbing the other Aspects and mutual Positions of the Stars the Day might be lengthned on Earth which exactly agreeth with the Litteral sense of the Sacred Text. But that of which if I be not mistaken we are to make no small account is That by help of this Copernican Hypothesis we have the Litteral apert and Natural Sense of another particular that we read of in the same Miracle which is That the Sun stood still in Medio Caeli Upon which passage grave Divines raise many questions in regard it seemeth very probable That when Joshuah desired the lengthning of the Day the Sun was near setting and not in the Meridian for if it had been in the Meridian it being then about the Summer Solstice and consequently the dayes being at the longest it doth not seem likely that it was necessary to pray for the lengthning of the day to prosecute Victory in a Battail the space of seven hours and more which remained to Night being sufficient for that purpose Upon which Grave Divines have been induced to think that the Sun was near setting And so the words themselves seem to sound saying Ne movearis Sol ne movearis For if it had been in the Meridian either it had been needless to have asked a Mircale or it would have been sufficient to have onely praid for some retardment Of this opinion is Cajetan to which subscribeth Magaglianes confirming it by saying that Joshua had that very day done so many other things before his commanding the Sun as were not possibly to be dispatch't in half a day Whereupon they are forced to read the Words in Medio Coeli to confess the truth with a little harshness saying that they import no more than this That the Sun stood still being in our Hemisphere that is above the Horizon But if I do not erre we shall avoid that and all other harsh expositions if according to the Copernican Systeme we place the Sun in the midst that is in the Centre of the Coelestial Orbes and of the Planetary Conversions as it is most requisite to do For supposing any hour of the day either Noon or any other as you shall please neerer to the Evening the Day was lengthened and all the Coelestial Revolutions stayed by the Suns standing still In the midst that is in the Centre of Heaven where it resides A Sense so much the more accomodate to the Letter besides what hath been said already in that if the Text had desired to have affirmed the Suns Rest to have been caused at Noon-day the proper expression of it had been to say It stood still at Noon-day or in the Meridian Circle and not in the midst of Heaven In regard that the true and only Middle of a Spherical Body as is Heaven is the Centre Again as to other places of Scripture which seem contrary to this position I do not doubt but that if it were acknowledged for True and Demonstrated those very Divines who so long as they repute it false hold those places incapable of Expositions that agree with it would finde such Interpretations for them as should very well suit therewith and especially if to the knowledge of Divine Learning they would but adde some knowledge of the Astronomical Sciences And as at present whilst they deem it false they think they meet in Scripture only with such places as make against it if they shall but once have entertained
Stadia or furlongs The Cause and Reason of whose Motion neither Ptolomy nor any other Astrologers could ever comprehend And yet the Reasons of these things are most plainly explained and demonstrated by Copernicus from the Motion of the Earth with which he sheweth that all the other Phaenomena of the Universe do more aptly accord Which opinion of his is not in the least contradicted by what Solomon saith in Ecclesiastes But the Earth abideth for ever For that Text signifieth no more but this That although the succession of Ages and generations of Men on Earth be various yet the Earth it self is still one and the same and continueth without any sensible alteration For the words run thus One Generation passeth away and another Generation cometh but the Earth abideth for ever So that it hath no coherence with its Context as Philosophers shew if it be expounded to speak of the Earths immobility And although in this Chapter Ecclesiastes and in many others Holy Writ ascribes Motion to the Sun which Copernicus will have to stand fixed in the Centre of the Universe yet it makes nothing against his Position For the Motion that belongs to the Earth is by way of speech assigned to the Sun even by Copernicus himself and those who are his followers so that the Revolution of the Earth is often by them phrased The Revolution of the Sun To conclude No place can be produced out of Holy Scripture which so clearly speaks the Earths Immobility as this doth its Mobility Therefore this Text of which we have spoken is easily reconciled to this Opinion And to set forth the Wonderful power and Wisdome of God who can indue and actuate the Frame of the Whole Earth it being of a monstrous weight by Nature with Motion this our Divine pen-man addeth And the pillars thereof tremble As if he would teach us from the Doctrine laid down that it is moved from its Foundations AN EPISTLE Of the Reverend Father PAOLO ANTONIO FOSCARINI A CARMELITE Concerning The PYTHAGORIAN and COPERNICAN Opinion OF The Mobility of the EARTH AND Stability of the SVN AND Of the New Systeme or Constituion OF THE WORLD IN WHICH The Authorities of SACRED SCRIPTVRE and ASSERTIONS of DIVINES commonly alledged against this Opinion are Reconciled WRITTEN To the most Reverend FATHER SEBASTIANO FANTONI General of the Order of CARMELITES Englished from the Original BY THOMAS SALVSBVRIE So quis indiget sapientia postulet à Deo Jacobi 1. versu 5. Optaevi datus est mihi sensus Sapientiae 7. versu 7. LONDON Printed by WILLIAM LEYBOVRN MDCLXI To the Most Reverend Father SEBASTIANO FANTONI General of the Order of CARMELITES IN obedience to the command of the Noble Signore Vincenzo Carraffa a Neapolitan and Knight of S. John of Jerusalem a person to speak the truth of so great Merit that in him Nobility of Birth Affability of Manners Universal knowledge of Arts and things Piety and Vertue do all contend for preheminence I resolved with my self to undertake the Defence of the Writings of the New or rather Renewed and from the Dust of Oblivion in which it hath long lain hid lately Revived Opinion Of the Mobility of the Earth and Stability of the Sun in times past found out first by Pythagoras and at last reduced into Practice by Copernicus who likewise hath deduced the Position of the Systeme and Constitution of the World and its parts from that Hypothesis on which Subject I have formerly writ to You Most Reverend Sir But in regard I am bound for Rome to preach there by your Command and since this Speculation may seem more proper for another Treatise to wit a Volume of Cosmography which I am in hand with and which I am daily busie about that it may come forth in company with my Compendium of the Liberal Arts which I have already finished rather than now to discuss it by it self I thought to forbear imparting what I have done for the present Yet I was desirous to give in the mean time a brief account of this my Determination and to shew You Most Reverend Father to whom I owe all my indeavours and my very self the Foundations on which this Opinion may be grounded least whilst otherwise it is favoured with much probability it be found in reality to be extreamly repugnant as at first sight it seems not onely to Physical Reasons and Common Principles received on all hands which cannot do so much harm but also which would be of far worse consequence to many Authorities of sacred Scripture Upon which account many at their first looking into it explode it as the most fond Paradox and Monstrous Capriccio that ever was heard of Which thing proceeds only from an antiquated and long confirmed Custome which hath so hardened men in and habituated them to Vulgar Plausible and for that cause by all men aswell learned as unlearned Approved Opinions that they cannot be removed one step from them So great is the force of Custome which not unfitly is stiled a second Nature prevailing over the whole World that touching things men are rather pleased with delighted in and desirous of those which though evil and obnoxious are by use made familiar to them than such wherewith though better they are not accustomed and acquainted So in like manner and that chiefly in Opinions which when once they are rooted in the Mind men start at and reject all others whatsoever not only those that are contrary to but even all that ever so little disagree with or vary from theirs as harsh to the Ear discoloured to the Eye unpleasant to the Smell nauseous to the Tast rough to the Touch. And no wonder For Physical Truths are ordinarily judged and considered by men not according to their Essence but according to the prescript of some one whose description or definition of them gaines him Authority amongst the vulgar Which authority nevertheless since 't is no more than humane ought not to be so esteemed as that that which doth manifestly appear to the contrary whether from better Reasons lately found out or from Sense it self should for its sake be contemned and slighted Nor is Posterity so to be confined but that it may and dares not only proceed farther but also bring to light better and truer Experiments than those which have been delivered to us by the Ancients For the Genius's of the Antients as in Inventions they did not much surpass the Wits of our times so for the perfecting of Inventions this Age of ours seems not only to equal but far to excell former Ages Knowledge whether in the Liberal or Mechanical Arts daily growing to a greater height Which Assertion might be easily proved were it not that in so clear a case there would be more danger of obscuring than hopes of illustrating it with any farther light But that I may not wholly be silent in this point have not the several Experiments of Moderns in many things stopped the mouth
greater measure than in those parts in which it is more swift and therefore ordinarily shall be also more deep and dangerous for passengers whence it is well said Take heed of the still Waters and this saying hath been since applied to things moral COROLLARIE VII LIkewise from the things demonstrated may be concluded that the windes which stop a River and blowing against the Current retard its course and ordinary velocity shall necessarily amplifie the measure of the same River and consequently shall be in great part causes or we may say potent con-causes of making the extraordinary inundations which Rivers use to make And it s most certain that as often as a strong and continual wind shall blow against the Current of a River and shall reduce the water of the River to such tardity of motion that in the time wherein before it run five miles it now moveth but one such a River will increase to five times the measure though there should not be added any other quantity of water which thing indeed hath in it something of strange but it is most certain for that look what proportion the waters velocity before the winde hath to the velocity after the winde and sueh reciprocally is the measure of the same water after the winde to the measure before the winde and because it hath been supposed in our case that the velocity is diminished to a fifth part therefore the measure shall be increased five times more than that which it was before COROLLARIE VIII WE have also probable the cause of the inundations of Tyber which befel at Rome in the time of Alexander the Sixth of Clement the Seventh which innundations came in a serene time and without great thaws of the Snows which therefore much puzzled the wits of those times But we may with much probability affirm That the River rose to such a height and excrescence by the retardation of the Waters dependant on the boistrous and constant Winds that blew in those times as is noted in the memorials COROLLARIE IX IT being most manifest that by the great abundance of Water the Torrents may increase and of themselves alone exorbitantly swell the River and having demonstrated that also without new Water but onely by the notable retardment the River riseth and increaseth in measure in proportion as the velocity decreaseth hence it is apparent that each of these causes being able of it self and separate from the other to swell the River when it shall happen that both these two causes conspire the augmentation of the River in such a case there must follow very great and irrepable innundations COROLLARIE X. FRom what hath been demonstrated we may with facility resolve the doubt which hath troubled and still poseth the most diligent but incautelous observers of Rivers who measuring the Streams and Torrents which fall into another River as those for instance which enter into the Po or those which fall into Tiber and having summed the total of these measures and conferring the measures of the Rivers and Brooks which fall into Tiber with the measure of Tiber and the measures of those which disimbogue into Po with the measure of Po they find them not equal as it seems to them they ought to be and this is because they have not well noted the most important point of the variation of velocity and how that it is the most potent cause of wonderfully altering the measures of running Waters but we most facilly resolving the doubt may say that these Waters diminish the measure being once entered the principal Channel because they increase in velocity COROLLARIE XI THrough the ignorance of the force of the velocity of the Water in altering its measure augmenting it when the velocity diminisheth and diminishing it when the velocity augmenteth The Architect Giovanni Fontana endeavoured to measure and and to cause to be measured by his Nephew all the Brooks and Rivers which discharged their Waters into Tiber at the time of the Innundation which happened at Rome in the year 1598 and published a small Treatise thereof wherein he summeth up the measures of the extraordinary Water which fell into Tiber and made account that it was about five hundred Ells more than ordinary and in the end of that Treatise concludeth that to remove the Innundation wholly from Rome it would be necessary to make two other Channels equal to that at present and that lesse would not suffice and finding afterwards that the whole Stream passed under the Bridge Quattro-Capi the Arch whereof is of a far less measure then five hundred Ells concludeth that under the said Bridge past a hundred fifty one Ells of Water compressed I have set down the precise term of comprest Water written by Fontana wherein I finde many errors The first of which is to think that the measures of these Waters compressed in the Channels of those Brooks and Rivers should maintain themselves the same in Tiber which by his leave is most false when ever those waters reduced into Tiber retain not the same velocity which they had in the place in which Fontana and his Nephew measured them And all this is manifest from the things which we have above explained for if the Waters reduced into Tiber increase in velocity they decrease in measure and if they decrease in velocity they increase in measure Secondly I consider that the measures of those Brooks and Rivers which enter into Tiber at the time of Innundation are not between themselves really the same when their velocities are not equal though they have the same names of Ells and Feet for that its possible that a disinboguement of ten Ells requadrated to speak in the phrase of Fontana of one of those Brooks might discharge into Tiber at the time of Innundation four ten and twenty times less Water than another mouth equal to the first in greatness as would occur when the first mouth were four ten or twenty times less swift than the second Whereupon whilst Fontana summes up the Ells and Feet of the measures of those Brooks and Rivers into a total aggregate he commits the same error with him which would add into one summe diverse moneys of diverse values and diverse places but that had the same name as if one should say ten Crowns of Roman money four Crowns of Gold thirteen Crowns of Florence five Crowns of Venice and eight Crowns of Mantua should make the same summe with forty Crowns of Gold or forty Crowns of Mantua Thirdly It might happen that some River or Current in the parts nearer Rome in the time of its flowing did not send forth more Water than ordinary and however it s a thing very clear that whilst the stream came from the superior parts that same Brook or River would be augmented in measure as hath been noted in the fourth Corollary in such sort that Fontana might have inculcated and noted that same River or Current as concurring to the Innundation although it
in the lower parts namely below the breach there is begot in the Channel of the River a certain ridge or shelf that is the bottom of the River is raised as is sufficiently manifest by experience and thus just in the same manner cutting the Bank at Bondeno there is at it were a breach made from which followeth the rising in the lower parts of the main Po being past the mouth of Pamaro which thing how pernitious it is let any one judge that understandeth these matters And therefore both for the small benefit and so many harms that ensue from maintaining this diversion I should think it were more sound advice to keep that Bank alwaies whole at Bondeno or in any other convenient place and not to permit that the Water of the Grand Po should ever come near to Ferara COROLLARIE XIV IN the Grand Rivers which fall into the Sea as here in Italy Po Adige And Arno which are armed with Banks against their excrescencies it s observed that far from the Sea they need Banks of a notable height which height goeth afterwards by degrees diminishing the more it approacheth to the Sea-coasts in such sort that the Po distant from the Sea about fifty or sixty miles at Ferara shall have Banks that be above twenty feet higher than the ordinary Water-marks but ten or twelve miles from the Sea the Banks are not twelve feet higher than the said ordinary Water-marks though the breadth of the River be the same so that the excrescence of the same Innundation happens to be far greater in measure remote from the Sea then near and yet it should seem that the same quantity of Water passing by every place the River should need to have the same altitude of Banks in all places But we by our Principles and fundamentals may be able to render the reason of that effect and say That that excesse of quantity of Water above the ordinary Water goeth alwaies acquiring greater velocity the nearer it approacheth the Sea and therefore decreaseth in measure and consequently in height And this perhaps might have been the cause in great part why the Tyber in the Innundation Anno 1578. issued not forth of its Channel below Rome towards the Sea COROLLARIE XV. FRom the same Doctrine may be rendred a most manifest reason why the falling Waters go lessening in their descent so that the same falling Water measured at the beginning of its fall is greater and bigger and afterwards by degrees lesseneth in measure the more it is remote from the beginning of the fall Which dependeth on no other than on the acquisition which it successively makes of greater velocity it being a most familiar conclusion among Philosophers that grave bodies falling the more they remove from the beginning of their motion the more they acquire of swiftnesse and therefore the Water as a grave body falling gradually velocitates and therefore decreaseth in measure and lesseneth COROLLARIE XVI ANd on the contrary the spirtings of a Fountain of Water which spring on high work a contrary effect namely in the beginning they are small and afterwards become greater and bigge and the reason is most manifest because in the beginning they are very swift and afterwards gradually relent their impetuosity and motion so that in the beginning of the excursion that they make they ought to be small and afterwards to grow bigger as in the effect is seen APPENDIX I. INto the errour of not considering how much the different velocities of the same running water in several places of its current are able to change the measure of the same water and to make it greater or lesse I think if I be not deceived that Ginlio Frontino a noble antient Writer may have faln in the Second Book which he writ of the Aqueducts of the City of Rome Whilst finding the measure of the Water Commentariis lesse than it was in erogatione 1263. Quinaries he thought that so much difference might proceed from the negligence of the Measures and when afterwards with his own industry he measured the same water at the beginning of the Aqueducts finding it neer 10000. Quinaries bigger than it was in Commentariis he judged that the overplus was imbeziled by Ministers and Partakers which in part might be so for it is but too true that the publique is almost alwayes defrauded yet neverthelesse I verily believe withal that besides the frauds of these Officers the velocities of the water in the place wherein Frontino measured it might be different from those velocities which are found in other places before measured by others and therefore the measures of the waters might yea ought necessarily to be different it having been by us demonstrated that the measures of the same running water have reciprocal proportion to their velocities Which Frontino not well considering and finding the water in Commentariis 12755. Quinaries in erogatione 14018 and in his own measure ad capita ductuum at the head of the fountain 22755. Quinaries or thereabouts he thought that in all these places there past different quantities of water namely greater at the fountain head then that which was in Erogatione and this he judged greater than that which was in Commentariis APPENDIX II. A Like mistake chanced lately in the Aqueduct of Acqua-Paola which Water should be 2000 Inches and so many effectively ought to be allowed and it hath been given in so to be by the Signors of Bracciano to the Apostolick-Chamber and there was a measure thereof made at the beginning of the Aqueduct which measure proved afterwards much lesse and short considered and taken in Rome and thence followed discontents and great disorders and all because this property of Running-Waters of increasing in measure where the velocity decreased and of diminishing in measure where the velocity augmented was not lookt into APPENDIX III. A Like errour in my judgement hath been committed by all those learned men which to prevent the diversion of the Reno of Bologna into Po by the Channels through which it at present runneth judged that the Reno being in its greater excrescence about 2000. feet and the Po being near 1000. feet broad they judged I say that letting the Reno into Po it would have raised the Water of Po two feet from which rise they concluded afterwards most exorbitant disorders either of extraordinary Inundations or else of immense and intolerable expences to the people in raising the Banks of Po and Reno and with such like weaknesses often vainly disturbed the minds of the persons concerned But now from the things demonstrared it is manifest That the measure of the Reno in Reno would be different from the measure of Reno in Po in case that the velocity of the Reno in Po should differ from the velocity of Reno in Reno as is more exactly determined in the fourth Proposition APPENDIX IV. NO less likewise are those Ingeneers and Artists deceived that have affirmed That letting the Reno into Po there would be
no rise at all in the Water of Po For the truth is That letting Reno into Po there would alwaies be a rising but sometimes greater sometimes lesse as the Po shall have a swifter or slower Current so that if the Po shall be constituted in a great velocity the rise will be very small and if the said Po shall be slow in its course then the rise will be notable APPENDIX V. ANd here it will not be besides the purpose to advertise That the measures partments and distributions of the Waters of Fountains cannot be made exactly unless there be considered besides the measure the velocity also of the Water which particular not being thorowly observed is the cause of continual miscariages in such like affairs APPENDIX VI. LIke consideration ought to be had with the greater diligence for that an errour therein is more prejudicial I say ought to be had by those which part and divide VVaters for the watering of fields as is done in the Territories of Brescia Bergama Crema Pavia Lodigiano Cremona and other places For if they have not regard to the most important point of the variation of the velocity of the VVater but onely to the bare Vulgar measure there will alwaies very great disorders and prejudices ensue to the persons concerned APPENDIX VII IT seemeth that one may observe that whilst the Water runneth along a Channel Current or Conduit its velocity is retarded withheld and impeded by its touching the Bank or side of the said Channel or Current which as immoveable not following the motion of the VVater interrupteth its velocity From which particular being true as I believe it to be most true and from our considerations we have an occasion of discovering a very nice mistake into which those commonly fall who divide the VVaters of Fountains VVhich division is wont to be by what I have seen here in Rome performed two wayes The first of which is with the measures of like figures as Circles or Squares having cut through a Plate of metal several Circles or Squares one of half an inch another of one inch another of two of three of four c. with which they afterwards adjust the Cocks to dispence the VVaters The other manner of dividing the VVaters of Fountains is with rectangle paralellograms of the same height but of different Bases in such sort likewise that one paralellogram be of half an inch another of one two three c. In which manner of measuring and dividing the Water it should seem that the Cocks being placed in one and the same plain equidistant from the level or superior superficies of the water of the Well and the said measures being most exactly made the VVater ought consequently also to be equally divided and parted according to the proportion of the measures But if we well consider every particular we shall finde that the Cocks as they successively are greater discharge alwaies more VVater than the just quantity in comparison of the lesser that is to speak more properly The VVater which passeth through the greater Cock hath alwaies a greater proportion to that which passeth through the lesser than the greater Cock hath to the lesser All which I will declare by an example The like errour occurreth also in the other manner of measuring the VVater of a Fountain as may easily be collected from what hath been said and observed above APPENDIX VIII THe same contemplation discovereth the errour of those Architects who being to erect a Bridge of sundry Arches over a River consider the ordinary breadth of the River which being v. g. fourty fathom and the Bridge being to consist of four Arches it sufficeth them that the breadth of all the four Arches taken together be fourty fathom not considering that in the ordinary Channel of the River the Water hath onely two impediments which retard its velocity namely the touching and gliding along the two sides or shores of the River but the same water in passing under the Bridge in our case meeteth with eight of the same impediments bearing and thrusting upon two sides of each Arch to omit the impediment of the bottom for that it is the same in the River and under the Bridge from which inadvertency sometimes follow very great disorders as quotidian practice shews us APPENDIX IX IT is also worthy to consider the great and admirable benefit that those fields receive which are wont to drink up the Rain-water with difficulty through the height of the water in the principal Ditches in which case the careful Husbandman cutteth away the reeds and rushes in the Ditches through which the waters pass whereupon may be presently seen so soon as the reeds and rushes are cut a notable Ebb in the level of the water in the Ditches insomuch that sometimes it is observed that the water is abated after the said cutting a third and more of what it was before the cutting The which effect seemingly might depend on this That before those weeds took up room in the Ditch and for that cause the water kept a higher level and the said Plants being afterwards cut and removed the water came to abate possessing the place that before was occupied by the weeds Which opinion though probable and at first sight satisfactory is nevertheless insufficient to give the total reason of that notable abatement which hath been spoken of But it is necessary to have recourse to our consideration of the velocity in the course of the water the chiefest and true cause of the variation of the measure of the same Running-Waterâ— for that multitudes of reeds weeds and plants dispersed through the current of the Ditch do chance notably to retard the course of the water and therefore the measure of the water increaseth and those impediments removed the same water gaineth velocity and therefore decreaseth in measure and consequently in height And perhaps this point well understood may be of great profit to the fields adjacent to the Pontine Fens and I doubt not but if the River Ninfa and the other principal Brooks of those Territories were kept well cleansed from weeds their waters would be at a lower level and consequently the drains of the fields would run into them more readily it being alwayes to be held for undoubted that the measure of the water before the cleansing hath the same proportion to the measure after cleansing that the velocity after the cleansing hath to the velocity before the cleansing And be cause those weeds being cleansed away the course ef the water notably increaseth it is therefore necessary that the said water abate in measure and become lower APPENDIX X. WE having above observed some errors that are committed in distributing the waters of Fountains and those that serve to water fields it seemeth now fit by way of a close to this discourse to advertise by what means these divisions may be made justly and without error I therefore think that one might two several wayes exquisitly divide
with industry truly heroicall and admirable by Monsignor Maffei Barherino then Prefect for the Wayes and now Pope And being necessitated that I might be able to walk in the Cave and for other causes I let down the Sluices of the said Cave at the mouth of the Lake No sooner were they stopt but a great many of the people of the Towns and Villages coasting upon the Lake flocking thither began to make grievous complaints that if those Sluices were kept shut not onely the Lake would want its due Vent but also the parts adjacent to the Lake would be over flown to their very great detriment And because at first appearance their motion seemed very reasonable I found my self hard put to it seeing no way to perswade such a multitude that the prejudice which they pretended I should do them by keeping the Sluices shut for two dayes was absolutely insensible and that by keeping them open the Lake did not ebb in the same time so much as the thickness of a sheet of Paper And therefore I was necessitated to make use of the authority I had and so followed my business as cause required without any regard to that Rabble tumultuously assembled Now when I am not working with Mattock or Spade but with the Pen and Discourse I intend to demonstrate clearly to those that are capable of reason and that have well understood the ground of this my Treatise that the fear was altogether vain which those people conceited And therefore I say that the Emissary or Sluice of the Lake of Perugia standing in the same manner as at present and the water passing thorow it with the same velocity as now to examine how much the Lake may abate in two days space we ought to consider what proportion the superficies of the whole Lake hath to the measure of the Section of the Emissary and afterwards to infer that the velocity of the water by the Emissary or Sluice shall have the same proportion to the abatement of the Lake and to prove thorowly and clearly this discourse I intend to demonstrate the following Proposition That which hath been demonstrated in the Vessel falls out exactly also in our Lake of Perugia and its Emissary and because the immensity of the superficies of the Lake is in proportion to the superficies of the Emissary or Sluice as many millions to one as may be easily calculated it is manifest that such abatement shall be imperceptible and almost nothing in two dayes space nay in four or six and all this will be true when we suppose that for that time there entreth no other Water into the Lake from Ditches or Rivolets which falling into the Lake would render such abatement yet less Now we see that it 's necessary to examine such abatements and risings with excellent reasons or at least with accurate experiments before we resolve and conclude any thing and how farre the vulgar are distant from a right judgement in such matters APPENDIX XIII FOR greater confirmation of all this which I have said I will instance in another like case which also I met with heretofore wherein for that the business was not rightly understood many disorders vast expences and considerable mischiefs have followed There was heretofore an Emissary or Sluice made to drain the Waters which from Rains Springs and Rivolets fall into a Lake to the end the shores adjoyning on the Lake should be free from the overflowing of the Waters but because perhaps the enterprize was not well managed and carried on it fell out that the Fields adjacent to the said Chanel could not drain but continued under water to which disorders a present remedy hath been used namely in a time convenient to stop up the Sluice by meanes of certain Floodgates kept on purpose for that end and thus abating the Level of the Water in the Emissary in the space of three or four dayes the Fields have been haply drained But on the other part the proprietors bordering on the Lake opposed this grievously complaining that whilst the Floodgates are shut and the course of the Water of the Sluice hindered the Lake overflowes the Lands adjacent by meanes of the Rivers that fell into it to their very great damage and so continuing their suits they got more of vexation than satisfaction Now being asked my opinion herein I judged it requisite since the point in controversie was about the rising and falling of the Lake that the said abatement when the Floodgates are open and increase when they are shut should be exactly measured and told them that it might be easily done at a time when no extraordinary Waters fell into the Lake neither of Rain or otherwise and the Lake was undisturbed by winds that might drive the Water to any side by planting neer to an Islet which is about the middle of the Lake a thick post on which should be made the marks of the Lakes rising and falling for two or three dayes I would not at that time pawn or resolutely declare my judgment in regard I might be by divers accidents misled But this I told them that by what I have demonstrated and particularly that which I have said above touching the Lake of Perugia I inclined greatly to think that these risings and fallings would prove imperceptible and inconsiderable and therefore that in case experience should make good my reason it would be to no purpose for them to continue disputing and wrangling which causeth according to the Proverb A great deal of cry but produceth not much Wool Lastly it importing very much to know what a Rain continued for many dayes can do in raising these Lakes I will here insert the Copy of a Letter which I writ formerly to Signior Galilaeo Galilaei chief Philosopher to the Grand Duke of Tuscany wherein I have delivered one of my conceits in this businesse and it may be by this Letter I may more strongly confirm what I have said above The Copy of a Letter to Signore GALILAEO GALILAEI Chief Philosopher to the most Serene Great Duke of TVSCANY Worthy and most Excellent SIR IN satisfaction of my promise in my former Letters of representing unto you some of my Considerations made upon the Lake Thrasimeno I say That in times past being in Perugia where we held our General Convention having understood that the Lake Thrasimeno by the great drought of many Moneths was much abated It came into my head to go privately and see this novelty both for my particular satisfaction as also that I might be able to relate the whole to my Patrons upon the certitude of my own sight of the place And so being come to the Emissary of the Lake I found that the Level of the Lakes surface was ebbed about five Roman Palmes of its wonted watermark insomuch that it was lower than the transome of the mouth of the Emissary by the length of this described line and therefore no Water issued out of the Lake to the great
of Fiume morto and that of Serchio by a little trench to see what advantage the Level E hath upon the Level I doth not give me full satisfaction taken so particularly for it may come to passe that sometimes E may be higher and sometimes A lower and I do not question but that when Serchio is low and Fiume morto full of Water the level of Fiume morto will be higher than that of Serchio But Serchio being full and Fiume morto scant of Water the contrary will follow if the Mouth shall be opened to the Sea And here it should seem to me that it ought to be considered that there is as much advantage from E to the Sea through the little Trench opened anew into Serchio as from E to the Sea by the Mouth of Fiume morto But the difficulty which is that we are to regard in our case is that the course of the Waters thorow the Trench is three times longer than the course of the Mouth of Fiume morto as appeareth by the Draught or Plat which you sent me which I know to be very exactly drawn for that the situation of those places are fresh in my memory Here I must give notice that the waters of Fiume morto determining thorow the Trench in Serchio the waters of which Fiume morto are for certain never so low as the Sea their pendency or declivity shall for two causes be lesse than the pendency of those waters through the Mouth towards the Sea that is because of the length of the line through the Trench and because of the height of their entrance into Serchio a thing which is of very great import in discharging the waters which come suddenly as he shall plainly see who shall have understood my Book of the Measure of Running Waters And this was the Reason why all the Countrey did grow dry upon the opening of the Mouth into the Sea And here I propose to consideration that which the Peasants about Pisa relate namely That the Water in the Fields doth no considerable harm by continuing there five or six yea or eight dayes And therefore the work of the Countrey is to open the Mouth of Fiume morto in such manner that the Water being come they may have the Trench free and ready when that the Water cometh it may have a free drain and may not stay there above eight or nine dayes for then the overflowings become hurtful It is to be desired also that if any Proposition is produced touching these affairs it might be propounded the most distinctly that may be possible and not consist in generals especially when the Dispute is of the risings of velocity of tardity of much and little water things that are all to be specified by measures 6. Your Letter saith in the next place that Signore Bartolotti confesseth that if the Mouth of the Fiume morto might alwayes be kept open it would be better to let it continue as it is the which that I may not yield to him in courtesie I confesse for the keeping it stopt on all sides would be a thing most pernicious But admitting of his confession I again reply that Fiume morto ought not to be let into Serchio but immediately into the Sea because although sometimes the Mouth to seawards be stopt up yet for all that the raising of the Bank above the Plains which is all the businesse of importance shall be ever lesser if we make use of the Mouth leading to the Sea than using that of Serchio 7. I will not omit to mention a kinde of scruple that I have concerning the position of Sign Bartolotti that is where he saith that the two Mouths A and D are equal to the like Mouths into the Sea Now it seems to me that the Mouth A of Fiume morto into Serchio is absolutely within Serchio nor can it be made lower and is regulated by the height of Serchio But the Mouth of Fiume morto terminates and ought to be understood to terminate in the Sea it self the lowest place And this I believe was very well perceived by Sig. Bartolotti but I cannot tell why he past it over without declaring it and we see not that the Mouth D falleth far from the Sea which Mouth ought to be let into the Sea it self and so the advantage of the Mouth into the Sea more clearly appeareth 8. That which Sig. Bartolotti addeth that when it is high Waters at such time as the Waters are out and when Winds choak up Fiume morto they not only retard it but return the course of the Waters upwards very leasurely perswadeth me more readily to believe that Sig. Bartolotti knoweth very well that the Mouth of Fiume morto let into Serchio is hurtful for by this he acknowledgeth that the Mouth towards the Sea doth in such sort drain the Countrey of the Waters as that they become very low and therefore upon every little impetus the waters turn their course And from the motions being exceeding slow is inferred that the abundance of Sea-water that cometh into Fiume morto is so much as is believed and as Sig. Bartolotti affirmeth 9. After that Sig. Bartolotti hath said what he promiseth above namely that when the Windes blowing strongly do stop up Fiume morto and not onely retard but turn the course upwards the time being Rainy and the Mouth of Fiume morto shut up the Waves of the Sea passe over the Bank of Fiume morto at that time saith Signore Bartolotti the Champain shall know the benefit of Fiume morto discharged into Serchio and the mouth A shall stand alwayes open and Fiume morto may alwayes constantly run out as also the Rains and Rain-waters although the hurtful Tempest should last many dayes c. And I reply that all the Art consists in this for the benefit of those Fields doth not depend on or consist in saying that Fiume morto is alwayes open and Fiume morto draineth continually But all the businesse of profit lyeth and consisteth in maintaining the Waters low in those Plaines and those Ditches which shall never be effected whilst the World stands if you let Fiume morto into Serchio but yet it may by opening the mouth into the Sea and so much reason and nature proveth and which importeth Experience confirmeth 10. In the tenth place I come to consider the answer that was made to another Proposition in the Letter which I writ to Father Francesco which prudently of it self alone might serve to clear this whole businesse I said in my Letter That great account is to be made of every small rising and ebbing of the Waters neer to the Sea in Fiume morto for that these risings and fallings although that they be small neer to the Sea-side yet neverthelesse they operate and are accompanied by notable risings and fallings within Land and far from the Sea-side and I have declared by an example of Arno in which a Land-flood falling that made it increase above its ordinary
Servant D. BENEDETTO CASTELLI Vpon this occasion I will here insert a Discourse that I made upon the Draining and improvement of the Pontine Fens for that I think that whatsoever may be done well and to purpose in this matter hath absolute dependance on the perfect knowledge of that so important Proposition by me demonstrated and explained in my Treatise of the Mensuration of Running Waters namely That the same water of a River doth continually change Measures according as it altereth and changeth the velocity of its course so that the measure of the thicknesse of a River in one Site to the measure of the same River in another Site hath the same proportion reciprocally that the velocity in this site hath to the velocity in the first site And this is a Truth so constant and unchangeable that it altereth not in the least point on any occurrences of the Water that change and being well understood it openeth the way to the knowledge of sundry advertisements in these matters which are all resolved by this sole Principle and from it are derived very considerable benefits and without these it is impossible to do any thing with absolute perfection A CONSIDERATION Upon the DRAINING OF THE Pontine Fenns BY D. BENEDETTO CASTELLI Abbot of S. BENEDETTO ALOISIO and Professor of the Mathematicks to P. Vrban VIII in the University of ROME CONSIDERATION III. AMongst the enterprizes by me esteemed if not absolutely impossible at least exceeding difficult one was that famous one of Draining the Pontine Fenns and therefore I was thorowly resolved never to apply my minde thereunto although by my Patrons I should be commanded to the same accounting that it was an occasion rather of losing reputation by the miscarriage of the attempt than of gaining fame by reducing things to a better pass then they now are at Yet nevertheless having of late years observed the place and sailed through those Chanels and those Waters after I had made some reflection thereupon I thought that the enterprize was not so difficult as I had at first conceited it to be and I am the more confirmed in this opinion upon the inducement of that which I have written Geometrically in my Treatise of the Mensuration of Running Waters so that talking with several persons I adventured to affirm in discoures that this improvement might possibly be brought into a good estate Now I have resolved to set down my thoughts in writing and to honour this my Paper with the Noble Name of your Lordship to render it the more credible and conspiâ—uous at the first view if it should chance that the Subject I treat of were not of such moment as that it did deserve to be valued for any other reason Pardon me Sir if I have been too bold and continue me in the number of your Servants The enterprize of Draining a great part of the Territories of the Pontine Fenns hath been undertaken both in the time of the antient Romans and last of all in our days yea in the late times by Sixtus V. I do not doubt in the least but that it will be possible yet to reduce things to a very good pass and if I be not mistaken with a very small charge in comparison of the profit that would be received from those rich Grounds This improvement was of great expence in the time of Sixtus Quintus but by reason the thing was not rightly understood there were made many Drains a great part of which were unprofitable and vain and amongst so many operations there hapned some to be made that succeeded as was desired but not being understood they were held in no account and thus the business being neglected the waters are returned into the same state as they were at first before the improvement Here I have by familiar discourses with my friends explained this enterprize undertaken by Sixtus V. and haply also by some more antient with the example of the Fable of Orilo in Ariosto This Monster was made up with such enchantment that men fought with him alwayes in vain for though in the Combate he were cut in pieces those divided Members presently re-united and returned to the fight more fierce then ever But the Paladine Astolfo coming to undertake him after a long dispute at the end he cut his head sheer off from the shoulders at one blow and nimbly alighting from his Horse took the Monstrous head and mounting again as he rid away he fell to shave the Pole of that Monster and so he lost the Lock of Hair in which alone the enchantment lay and then the horrible Head in an instant manifested signs of death and the trunk which ran seeking to reunite to it anew gave the last gasp and in this manner the enchantment ended The Book of Fate served admirably to the Paladine whereby he came to understand that Charm for by shaving his whole head the enchanted hairs came to be cut off amongst the rest In the same manner I say that it hath sometimes happened in Draining those Fields for that amongst so many tryals as have been made that also was light upon on which the improvement and remedy to the disorder did depend And to us my fore-named Treatise shall serve for a Rule which being well understood shall make us to know wherein consisteth and whereon dependeth this miscarriage and consequently it will be easie to apply thereunto a seasonable remedy Another head to which these harms may be reduced but proceeding from the same Root which hath a great part in this disorder is the impediment of those Wears in the River which are made by heightning the bed of the same for placing of fishing-nets of which Piscaries I reckoned above ten when I made a voyage thorow those waters to Sandolo And these Fishing-Wears are such impediments that some one of them makes the water of the River in the upper part to rise half a Palm and sometimes a whole Palm and more so that when they are all gathered together these impediments amount to more than seven or possibly than eight Palms There concurreth for a third most Potent Cause of the waters continuing high in the evacuating or Draining Chanel and consequently on the Plains The great abundance of water that issueth from Fiume Sisto the waters of which do not keep within its Banks when they are abundant but encreasing above its Chanel they unite with those of the Evacuator and dispersing thorow the Fens are raised with great prejudice and much greater than is conceived according to what hath been demonstrated in the Second Consideration upon the Lake of Venice Nor is it to any purpose to say that if we should measure all the Waters that disimbogue from Fiume Sisto and gather them into one summe we should not finde them to be such as that they shall be able to make the Waters of the Fens to increase by reason of the great expansion of them over which that body of water is to
to carry it into Main-Po at Stellata for the Reasons that Cardinal Capponi most ingeniously enumerates in a short but well-grounded Tract of his not because that indeed it would not both by Purlings and by Breaches occasion some inconvenience especially in the beginning but because I hold this for the incomodities of it to be a far less evil than any of the rest and because that by this means there is no occasion given to them of Ferrara to explain that they are deprived of the hope of ever seeing the Po again under the Walls of their City To whom where it may be done it is but reason that satisfaction should be given It is certain that Po was placed by Nature in the midst of this great Valley made by the Appennine Hills and by the Alps to carry as the Master-Drain to the Sea that is the grand receptacle of all Waters those particular streams which descend from them That the Reno by all Geographers Strabo Pliny Solimas Mella and others is enumerated among the Rivers that fall into the said Po. That although Po should of it self change its course yet would Reno go to look it out if the works erected by humane industry did not obstruct its passage so that it neither is nor ought to seem strange if one for the greater common good should turn it into the same Now at Stellata it may go several waies into Po as appeareth by the levels that were taken by my Order of all which I should best like the turning of it to la Botta de' Ghislieri carrying it above Bondeno to the Church of Gambarone or a little higher or lower as shall be judged least prejudicial when it cometh to the execution and this for two principal reasons The one because that then it will run along by the confines of the Church Pâ—trimony without separating Ferrara from the rest of it The other is Because the Line is shorter and consequently the fall greater for that in a space of ten miles and one third it falleth twenty six feet more by much than is required by Artists and would go by places where it could do but little hurt notwithstanding that the persons interressed study to amplifie it incredibly On the contrary there are but onely two objections that are worthy to be examined One That the Drains and Ditches of S. Bianca of the Chanel of Cento and of Burana and all those others that enter into Po do hinder this diversion of Reno by the encreasing of the waters in the Po. The other is that Po rising about the Transom of the Pilaster-Sluice very near 20 feet the Reno would have no fall into the same whereupon it would rise to a terrible height at which it would not be possible to make or keep the Banks made so that it would break out and drown the Meadowes and cause mischiefs and damages unspeakable and irreparable as is evident by the experiment made upon Panaro which being confined between Banks that it might go into Po this not being neither in its greatest excrescense it broke out into the territories of Final and of Ferrara And though that might be done it would thereupon ensue that there being let into the Chanel of Po 2800. square feet of water for so much we account those of Reno and Panaro taken together in their greatest heights the superficies of it would rise at least four feet insomuch that either it would be requisite to raise its Banks all the way unto the Sea to the same height which the treasures of the Indies would not suffice to effect or else there would be a necessity of enduring excessive Breaches To these two Heads are the Arguments reduced which are largely amplified against our opinion and I shall answer first to the last as most material I say therefore that there are three cases to be considered First Po high and Reno low Secondly Reno high and Po low Thirdly Reno and Po both high together As to the first and second there is no difficulty in them for if Po shall not be at its greatest height Reno shall ever have a fall into it and there shall need no humane Artifice about the Banks And if Reno shall be low Po shall regurgitate and flow up into the Chanel of it and also from thence no inconvenience shall follow The third remains from which there are expected many mischiefs but it is a most undoubted truth that the excrescencies of Reno as coming from the adjacent Appennines and Rains are to continue but seven or eight hours at most and so would never or very rarely happen to be at the same time with those of Po caused by the melting of the snowes of the Alps at least 400. miles distance from thence But because it sometimes may happen I reply that when it cometh to pass Reno shall not go into Po but it shall have allowed it one or two Vents namely into the Chanel of Ferrara as it hath ever had and into Sanmartina where it runneth at present and wherewith there is no doubt but that the persons concerned will be well pleased it being a great benefit to them to have the water over-flow their grounds once every four or five years instead of seeing it anoy them continually Yea the Vent may be regulated reserving for it the Chanel in which Reno at present runneth and instead of turning it by a Dam at la Betta de Ghislieri perhaps to turn it by help of strong Sluices that may upon all occasions be opened and shut And for my part I do not question but that the Proprietors themselves in Sanmartina would make a Chanel for it which receiving and confining it in the time of the Vents might carry the Sand into the Po of Primaro Nor need there thence be feared any stoppage by Mud and Sand since that it is supposed that there will but very seldom be any necessity of using it so that time would be allowed upon occasion to scowr and cleanse it And in this manner all those Prodigies vanish that are raised with so much fear from the enterance of the Water of Reno swelled into Po when it is high to which there needeth no other answer yet neverthelesse we do not take that quantity of Water that is carried by Reno and by Panaro to be so great as is affirmed For that P. D. Benedetto Castelli hath no lesse accutely than accurately observed the measures of this kind noting that the breadth and depth of a River is not enough to resolve the question truly but that there is respect to be had to the velocity of the Waters and the term of time things hitherto not considered by the Skilful in these affairs and therefore they are not able to say what quantity of Waters the said Rivers carry nor to conclude of the risings that will follow thereupon Nay it is most certain that if all the Rivers that fall into Po which are above thirty should rise at the
judgements are approved in these affairs I return now from where I degrest and affirm it as indubitable that Reno neither can nor ought to continue longer where it at this day is and that it cannot go into any other place but that whither Cardinal Capponi designed to carry it and which at present pleaseth me better than any other or into Volana whence it was taken away the vigilance of Men being able to obviate part of those mischiefs which it may do there But from its Removal besides the alleviation of the harm which by it self is caused there would also result the diminution of that which is occasioned by the other Brooks to the right hand of the Po of Argenta forasmuch as the said Po wanting all the water of Reno it would of necessity come to ebb in such manner that the Valleys would have a greater Fall into the same and consequently it would take in and swallow greater abundance of water and by this means the Ditches and Draines of the Up-Lands would likewise more easily Fall into them especially if the scouring of Zenzalino were brought to perfection by which the waters of Marrara would fall into Marmorta And if also that of Bastia were enlarged and finished by which there might enter as much water into the said Po of Argenta as is taken from it by the removal of Reno although that by that meanes the water of the Valleys would asswage double Nor would the people of Argenta the Isles of S. Giorgio and Comacchio have any cause to complain for that there would not be given to them more water than was taken away Nay sometimes whereas they had Muddy waters they would have clear nor need they to fear any rising And furthermore by this means a very great quantity of ground would be restored to culture For the effecting of all which the summ of 50. thousand Crowns would go very far and would serve the turn at present touching those Brooks carrying them a little farther in the mean time to fill up the greater cavities of the Valleys that we might not enter upon a vaster and harder work that would bring with it the difficulties of other operations and so would hinder the benefit which these people expect from the paternal charity of His Holiness TO The Right Honourable MONSIGNORE D. Ferrante Cesarini MY Treatise of the MENSURATION of RUNNING WATERS Right Honourable and most Noble Sir hath not a greater Prerogative than its having been the production of the command of Pope Vrban VIII when His Holiness was pleased to enjoyn me to go with Monsignore Corsini in the Visitation that was imposed upon him in the year 1625. of the Waters of Ferrara Bologna Romagna and Romagnola for that on that occasion applying my whole Study to my service and duty I published in that Treatise some particulars till then not rightly understood and considered that I knew by any one although they be in themselves most important and of extraordinary consequence Yet I must render thanks to Your Lordship for the honour you have done to that my Tract but wish withal that your Esteem of it may not prejudice the universal Esteem that the World hath of Your Honour most refined judgement As to that Point which I touch upon in the Conclusion namely That the consideration of the Velocity of Running Water supplyeth the consideration of the Length omitted in the common way of measuring Running Waters Your Lordship having commanded me that in favour of Practise and for the perfect discovery of the disorder that commonly happeneth now adayes in the distribution of the Waters of Fountains I should demonstrate that the knowledge of the Velocity serveth for the finding of the Length I have thought fit to satisfie your Command by relating a Fable which if I do not deceive my self will make out to us the truth thereof insomuch that the rest of my Treatise shall thereby also become more manifest and intelligible even to those who finde therein some kinde of obscurity In the dayes of yore before that the admirable Art of Weaving was in use there was found in Persia a vast and unvaluable Treasure which consisted in an huge multitude of pieces of Ermesin or Damask I know not whether which as I take it amounted to near two thousand pieces which were of such a nature that though their Breadth and Thickness were finite and determinate as they use to be at this day yet nevertheless their Length was in a certain sense infinite for that those two thousand pieces day and night without ceasing issued out with their ends at such a rate that of each piece there issued 100. Ells a day from a deep and dark Cave consecrated by the Superstition of those people to the fabulous Arachne In those innocent and early times I take it to have been in that so much applauded and desired Golden age it was left to the liberty of any one to cut off of those pieces what quantity they pleased without any difficulty But that felicity decaying and degenerating which was altogether ignorant of Meum and Tuum terms certainly most pernicious the Original of all evils and cause of all discords there were by those people strong and vigilant Guards placed upon the Cave who resolved to make merchandize of the Stuffes and in this manner they began to set a price upon that inestimable Treasure selling the propriety in those pieces to divers Merchants to some they sold a right in one to some in two and to some in more But that which was the worst of all There was found out by the insatiable avarice of these men crafty inventions to deceive the Merchants also who came to buy the aforesaid commodity and to make themselves Masters some of one some of two and some of more ends of those pieces of stuff and in particular there were certain ingenuous Machines placed in the more secret places of the Cave with which at the pleasure of the Guards they did retard the velocity of those Stuffs in their issuing out of the Cave insomuch that he who ought to have had 100. Ells of Stuff in a day had not above 50 and he who should havâ— had 400 enjoyed the benefit of 50. onely and so all the rest were defrauded of their Rights the surplusage being sold appropriated and shared at the will of the corrupt Officers So that the business was without all order or justice insomuch that the Goddess Arachne being displeased at those people deprived every one of their benefit and with a dreadful Earthquake for ever closing the mouth of the Cave in punishment of so much impiety and malice Nor did it avail them to excuse themselves by saying that they allowed the Buyer the Breadth and Thickness bargained for and that of the Length which was infinite there could no account be kept For the wise and prudent Priest of the Sacred Grotto answered That the deceit lay in the length which they were defrauded of
against the Law of God Since that thereby the same measure is made sometimes greater and sometimes lesser A disorder so enormous and execrable that I shall take the boldness to say that for this sole respect it ought to be condemned and prohibited likewise by human Law which should Enact that in this business there should be imployed either this our Rule or some other that is more exquisite and practicable whereby the measure might keep one constant and determinate tenor as we make it and not as it is now to make Pondus Pondus Mensura Mensura And this is all that I had to offer to your most Illustrious Lordship in obedience to your commands reserving to my self the giving of a more exact account of this my invention when the occasion shall offer of reducing to practice so holy just and necessary a reformation of the Measure of Running Waters and of Aqueducts in particular which Rule may also be of great benefit in the division of the greater Waters to over-flow Grounds and for other uses I humbly bow Your Most Devoted and Most Obliged Servant D. Benedetto Castelli Abb. Casin FINIS A TABLE Of the most observable matters in this Treatise of the MENSURATION of RUNNING WATERS A ABatements of a River in different and unequal Diversions is alwaies equal which is proved with 100. Syphons Page 75 Arno River when it riseth upon a Land-Flood near the Sea one third of a Brace it riseth about Pisa 6. or 7. Braces 82 B Banks near to the Sea lower than far from thence Corollary XIV 16 Brent River diverted from the Lake of Venice and its effects 64 Brent supposed insufficient to remedy the inconveniences of the Lake and the falsity of that supposition 67 Brent and its benefits in the Lake 70 Its Deposition of Sand in the Lake how great it is 78 79 Bridges over Rivers and how they are to be made Appendix VIII 20 Burana River its rising and falling in Panaro 110 C Castelli applyed himself to this Study by Order of Urban VIII 2 Chanel of Navigation in the Valleys of Bologna and its inconveniences 99 Carried into the Po of Ferrara and its benefits ibid. Ciampoli a lover of these Observations of Waters 3 D Difficulty of this business of Measuring Waters 2 Disorders that happen in the distribution of the Waters of Aqueducts and their remedies 113 Distribution of the Waters of Fountains and Aqueducts Appendix X. 22 Distribution of Water to over-flow Grounds Appendix XI 23 69 70 Diversion of Reno and other Brooks of Romagna advised by P. Spernazzati to what end it was 100 Drains and Ditches the benefit they receive by cutting away the Weeds and Reeds Appendix IX 21 Drains and Sewers obstructed in the Diversion of Reno into Main Po and a remedy for the same 110 E Engineers unvers'd in the matter of Waters 2 Erour found in the common way of Measuring Running Waters 68 69 Errour inderiving the Water of Acqua Paola Appendix II. 17 18 Errour of Bartolotti 86 87 Errours of Engineers in the Derivation of Chenels Corollary XII 12 Errour of Engineers in Measuring of Reno in Po. Appendix III. ibid. Errour of other Engineers contrary to the precedent Appendix IV. ibid. Errour of Giovanni Fontana in Measuring Waters Corollary XI 9 Errour of Giulio Frontino in Measuring the Waters of Aqueducts Appendix I. 17 Errours committed in cutting the Bank at Bondeno in the swellings of Po Corollary XIII 81 F Fenns Pontine Drained by Pope Sixtus Quintus with vast expence 92 The ruine and miscarriage thereof 93 Tardity of the principal Chanel that Drains them cause of the Drowning ibid. They are obstructed by the Fishing-Wears which swell the River 94 Waters of Fiume Sisto which flow in great abundance into the Evacuator of the said Fenns 94 95 Remedies to the disorders of those Fenns 95 96 Fontana Giovanni his errours in Measuring Waters Corollary XI 9 Fiume Morto whether it ought to fall into the Sea or into Serchio 79 Let into Serchio and its inconveniences 79 80 The dangerous rising of its Waters when to be expected 81 Its inconveniences when it is higher in level than Serchio and why it riseth most On the Sea-coasts at such time at the Winds make the Sea to swell 83 G Galilaeo Galilaei honourably mentioned Page 2 28 His Rules for measuring the time 49 H Height vide Quick Heights different made by the same stream of a Brook or Torrent according to the divers Velocities in the entrance of the River Corollary I. 6 Heights different made by the Torrent in the River according to the different heights of the River Corollary II. ibid. K Knowledge of Motion how much it importeth 1 L Lake of Perugia and he Observation made on it Appendix XII 42 Lake of Thrasimenus and Considerations upon it a Letter written to Sig. Galilaeo Galilaei 28 Lake of Venice and Considerations upon it 63 73 Low Waters which let the bottom of it be discovered 64 The stoppage and choaking of the Ports a main cause of the disorders of the Lake and the grand remedy to those disorders what it is 66 Lakes and Meers along the Sea-ccosts and the causes thereof 65 Length of Waters how it is to be Measured 70 M Measure and Distributions of Waters Appendix V. 18 Measure of Rivers that fall into others difficult Coroll X. 9 Measure of the Running Water of a Chanel of an height known by a Regulator of a Measure given in a time assigned Proposition I. Problem I. 50 Measure of the Water of any River of any greatness in a time given Proposition V. Problem III. 60 Measure that shewes how much Water a River dischargeth in a time given 48 Mole-holes Motion the principal subject of Philosophy 1 Mud. Vide Sand. N Navigation from Bologna to Ferrara is become impossible till such time as Reno be diverted 101 Navigation in the Lake of Venice endangered and how restored 65 70 P Perpendicularity of the Banks of the River to the upper superficies of it 37 Perpendicularity of the Banks to the bottom 37 Perugia Vide Lake Pontine Vide Fenns Ports of Venice Malamocco Bondolo and Chiozza choaked up for wâ—nt of Water in the Lake 65 Proportions of unequal Sections of equal Velocity and of equal Sections of unequal Velocity Axiome IV. and V. 38 Proportions of equal and unequal quantities of Water which pass by the Sections of different Rivers Proposition II. 39 Proportions of unequal Sections that in equal times discharge equal quantities of Water Proposition III. 41 Proportion wherewith one River falling into another varieth in height Proposition IV. 44 Proportion of the Water discharged by a River in the time of Flood to the Water discharged in an equal time by the said River before or after the Flood Proposition V. 44 Proportion of the Heights made by two equal Brooks or Streams falling into the same River Proposition VI. 45 Proportion of the Water which a River dischargeth encreasing in Quick-height
Litigious Lawyers that are extertained in an ill cause keep close to sâ—me exâ—ression fallen from the adverse party at unawares * Or progressions The apparent diversity of motion in the Planets is insensible in the fixed Stars Supposing that a fixed Star of the sixth magnitude is no bigger than the Sun the diversitie which is so great in the Planets in the fixed Stars is almost insensible The distance of the Sun containeth 1208 Semid of the Earth * The Diameter of the Sun half a degree The Diameter of a fixed Star of the first magnitude and of one of the sixth The apparent Diameter of the Sun how much it is bigger than that of a fixed star The distance of a fixed star of the sixth magnitude how much it is the star being supposed to be equal to the Sun In the fixed stars the diversitie of aspect caused by the grand Orb is little more then that caused by the Earth in the Sun A star of the sixth magnitude supposed by Tycho and the Authour of the Book of Conclusions an hundred and six milions of times bigger than needs The computation of the magnitude of the fixed Stars in respect to the grand Orb. A common errour of all the Astronomers touching the magnitude of the stars Venus renders the errour of Astronomers in determining the magnitudes of stars inexcusable A way to measure the apparent diameter of a star * Rendred in Latine Corum that is to say North-west * i. e. Is subtended by The diameter of a fixed star of the first magnitude not more than five sec. min. The circle of the pupil of the eye enlargeth and contracteth * Panicum a small grain like to Mill I take it to be the same with that called Bird Seed * Strisce How to find the distance of the rays concourse from the pupil All Astronomers agree that the greater magnitudes of the Orbes is the cause of the tardity of the conversions By another supposition taken from Astronomers the distance of the fixed Stars is calculated to be 10800 semidiameters of the grand Orb. By the proportion of Jupiter and of Mars the starry Sphere is found to be yet more remoâ—e Immeâ—se magnitudes and numbers are incomprehensible by our understanding God Nature do imploy themselves in caring for men as if they minded nothing else An example of Gods care of mankind taken from the Sun It is great rashnesse to censure that to be superfluous in hâ—ll verse which we do not perceive to be made for us By depriving Heaven of some star one might come to know what influence it hath upon us Many things may be in Heaven that are invisible to us Great small immense c. are relative terms Vanity of those mens discourse who judg the starry sphere too vast in the Copernican Hypothesis * Spelloncola which is here put for the lâ—ast of Fishes The space assigned to a fixed star is much lesse than that of a Planet A star is called in respect of the space that environs it The whole starry sphere behold from a great distance might appear as small as one single star Instances of the Authour of the Conclusions by way of interogation * Or Gulph Answers to the interrogatories of the said Authour The Authour of the Conclusions confound and contradicts himself in his interrogations Interrogatories put to the Authour of the Conclusions by which the weaknesse of his is made appear That remote objects appeare so small is the defect of the eye as is demonstrated Tycho nor his followers ever attempted to see whether there are any appearances in the Firmament for or against the annual mâ—tion Astronomers perhaps have not known what appearances ought to follow upon the annual motion of the Earth Copernicus understood not some things for want of Instruments Tycho and others argue against the annual motion from the invariable elevation of the Pole * Christophorus Rothmannus Motion 〈◊〉 it is common is as if it never were An example fitted to prove that the altitude of the Pole ought not to vary by means of the Earths annual motion * Corsia the bank or bench on which slaves sit in a Gally Upon the annual motion of the Earth alteration may ensue in some fixed star not in the Pole The equivoke of those who believe that in the annual motion great mutations are to be made about the elevation of a fixed star is confuted The right line and circumference of an infinite circle are the same thing Enquiry is made what mutations in what stars are to be discovered by means of the annual motion of the Earth Astronomers having omitted to instance what alterations those are that may be derived from the annual motion of the Earth do thereby testifie that they never rightly understood the same The mutations of the fixed stars ought to be in some greater in others lesser and in others nothing at all * Bandola that end of a skeen wherewith housewives fasten their hankes of yarn thread or silk The grand difficulty in Copernicus his Doctrine is that which concerns the Phaenomena of the Sun and fixed stars * Pettine it is the stay in a Weavets Loom that permitteth no knot or snarle to passe it called by them the Combe of the Loom Aristotles argument against the Ancients who held that the Earth was a Planet The annual motion made by the centre of the Earth under the Ecliptick and the diurnal motion made by the Earth about its own centre The axis of the Earth continueth alwayes parallel to it self and describeth a Cylindraical superficies inclining to the grand Orb. The Orb of the Earth never inclineth but is immutably the same The fixed stars placed in the Ecliptick never elevate nor descend on account of the annual motion but yet approach and recede Objections against the Earths annual motion taken from the fixed stars placed in the Ecliptick * Or will prove of good alloy The station direction and retrogradation of the Planets is known in relation to the fixed stars An Indice is the fixed stars like to that which is 〈◊〉 in the Planeâ—s is an argument of the Earths annual motion The fixed stars without the Ecliptick elevate and descend more or lesse according to their distance from the said Ecliptick * i. e. of the Ecliptick The Earth approacheth or recedeth from the fixed stars of the Ecliptick the quantity of the Diameter of the Grand Orb. The stars nearer to us make greater differences than the more remote The Epilogue of the Phaenomena of the fixed stars caused by the annual motion of the Earth In objects far remote and luminous a small approach or recession is imperceptible If in the fixed stars one should discover any annual mutation the motion of the Earth would be undeniable It is proved what small credit is to be given to Astronomical Instruments in minute observations * Braccia Italian * Or Miâ— Ptolomy did not trust to an Instrument made by Archimedes Instruments
of Tycho made with great expence What Instruments are apt for most exact observation * Italian braces An exquisite observation of the approach and departure of the Sun from the Summer Solstice A place accommodated for the observation of the fixed stars as to what concers the annual motion of the Earth The Copernican Systeme difficult to be understood but easie to be effected Necessary prepositions for the better conceiving of the consequences of the Earths motion A plain Scheme representing the Copernican Hypothesis and its consequences Axiomes commonly admitted by all Philosophers Aristotle taxeth Plato for being too studious of Geometry Peripatetick Philosophers condemn the Study of Geometry and why Four several motions assigned to the Earth The motion of descent belongs not to the terrestrial Globe but to its parts The annual and diurnal motion are compatible in the Earth Every pensil and librated body carryed round in the circumference of a circle acquireth of it self a motion in it self contrary to that An Experiment which sensibly shews that two contrary motions may naturally agree in the same moveable The third motion ascribed to the Earth is rather a resting immoveable An admirable intern vertue of the terrestrial Globe of alwayes beholding the same part of Heaven The terrestrial Globe made of Loade-stone * An eminent Doctor of Physick our Countreyman born at Colchester and famous for this his learned Treatise published about 60 years since at London The Magnetick Philosophy of William Gilbert The Pusillanimity of Popular Wits The Terrestrial Globe composed of sundry matters The interne parts of the terrestrial Globe must of necessity be solid * Or MOULD * Of which with the Latin translatour I must once more professe my self ignorant Our Globe would have been called stone in stead of Earth of that name had been giuen it in the beginning The method of Gilbert in his Philosophy Many properties in the Magnet 〈…〉 The Magnet armed takes up much more Iron than when armed * Or Closet of rarities The first observers and inventers of things ought to be admired The true cause of the multiplication of vertue in the Magnet by means of the arming Of a new effect its necessary that the cause be likewise new It is proved that Iron consists of parts more subtil pure and compact than the magnet A sensible proof of the impurity of the Magnet * The Author hereby meaneth that the stone doth not all consist of magnetick matter but that the whiter specks being weak those other parts of the Loadstone of a more dark constant colour contain all that vertue wherewith bodies are attracted * A common sewing needle Sympathy and Antipathy terms used by Philosophers to give a reason easily of many natural effests A pleasant example declaring the invalidity of some Phylosophical argumentations The several natural motions of the Magnet Aristole grants a compound motion to mixt bodies The motion of mixt bodies ought to be such as may result from the composition of the motions of the simple bodies compounding With two right motions one cannot compose circular motions Philosophers are forced to confesse that the Magnet is compounded of coelestial substances and of elementary The errour of those who call the Magnet a mixt body and the terrestrial Globe a simble body * Ogliopotrida a Spanish dish of many ingredients boild together The Discourses of Peripateticks full of errours and contradictions An improbable effect admired by Gilbertus in the Loadstone The vain argumentation of some to prove the Element of Water to be of a Spherical superficies Nature in sport maketh the ebbing and flowing of the Sea to approve the Earthâ— mobility The tide and mobility of the Earth mutually confirm each other All terrene effects indifferently confirm the motion or rest of the Earth except the ebbing and flowing of the Sea The first general conclusion of the impossibility of the ebbing and flowing the immobility of the terrestrial Globe being granted The knowledge of the effests contributes to the investigation of the causes Three Periods of ebbings and flowings diurnal monethly and annual Varieties that â—appen in the diurâ—â—â— period * A Strair so called * Or Ilva * Or Crets The cause of the ebbing and flowing alledged by a certain modern Philosopher The cause of the ebbing and flowing ascribed to the Moon by a certain Prelate Hieronymus Borrius and other Peripateticks refer it to the temperate heat of the Moon Answers to the vanities alledged as causes of the ebbing and flowing * Or rather smooth The Isles are tokens of the unevennesse of the bottomes of Seas Poetick wits of two kinds Truth hath not so little light as not to be discovered amidst the umbrages of falshoods Aristotle holdeth those effects to be miraculous of which the causes are unknown It is proved impossible that there should naturally be any ebbing and flowing the Earth being immoveable * Palms †Lio is a fair Port in the Venetian Gulph lying N. E. from the City True and natural effects follow without difficulty Two sorts of motions of the containing Vessel may make the contained water to rise and fall The Cavities of the Earth cannot approach or go farther from the centre of the same The progpessive and uneven motion may make the water contained in a Vessel to run to and fro * A Town lying S. E. of Venice The parts of the terrestrial Globe accelerate and regard in their motion Demonstrations how the parts of the terrestriall Globe accelerate and retard The parts of a Circle regularly moved about its own centre move in divers times with contrary motions The mixture of the two motions annnal and diurnal causeth the inequality in the motion of the parts of the terrestrial Globe The most potent and primary cause of the ebbing and flowing Sundry accidents that happen in the ebbings flowings The first accident The Water raised in one end of the Vessel returneth of its self to Aequilibrium In the shorter Vessels the undulations of waters are more frequent The greater profundity maketh the undulations of waters more frequent Water riseth falleth in the extream parts of the Vessel and runneth to and fro in the midst An accident of the Earths motions impossible to be reduced to practice by art Reasons renewed of the particnlar accidents observed in the ebbings and flowings Second causes why in small Seas and in Lakes there are no ebbings and flowings The reason given why the ebbings and flowings for the most part are every six hours The cause why some Seas though very long suffer no ebbing and flowing Ebbings and flowings why greatest in the extremities of Gulphs and least in the middle parts Why in narrow places the course of the waters is more swift than in larger A discussion of 〈…〉 â—abstruce 〈…〉 obseâ—ved 〈…〉 ebbing and â—â—â—wing The cause why in some narrow Channels we see the Sea-waters run alwayes one way * Or current The Hypothesis of the Earths mobility taken in favour of the
the undeceiving of this Philosopher that I could advise him that some time or other going by water he would carry along with him a Vessel of reasonable depth full of water and prepare a ball of wax or other matter that would descend very slowly to the bottome so that in a minute of an hour it would scarce sink a yard and that rowing the boat as fast as could be so that in a minute of an hour it should run above an hundred yards he would let the ball submerge into the water freely descend diligently observe its motion If he would but do thus he should see first that it would go in a direct line towards that point of the bottom of the vessel whither it would tend if the boat should stand still to his eye and in relation to the vessel that motion would appear most straight and perpendicular and yet he could not say but that it would be composed of the right motion downwards and of the circular about the element of water And if these things befall in matters not natural and in things that we may experiment in their state of rest then again in the contrary state of motion and yet as to appearance no diversity at all is discovered that they seem to deceive our sense what can we distinguish touching the Earth which hath been perpetually in the same constitution as to motion and rest And in what time can we experiment whether any difference is discernable amongst these accidents of local motion in its diverse states of motion and rest if it eternally indureth in but one onely of them SAGR. These Discourses have somewhat whetted my stomack which those fishes and snails had in part nauseated and the former made me call to minde the correction of an errour that hath so much appearance of truth that I know not whether one of a thousand would refuse to admit it as unquestionable And it was this that sailing into Syria and carrying with me a very good Telescope that had been bestowed on me by our Common Friend who not many dayes before had invented I proposed to the Mariners that it would be of great benefit in Navigation to make use of it upon the round top of a ship to discover and kenne Vessels afar off The benefit was approved but there was objected the difficulty of using it by reason of the Ships continual fluctuation and especially on the round top where the agitation is so much greater and that it would be better for any one that would make use thereof to stand at the Partners upon the upper Deck where the tossing is lesse than in any other place of the Ship I for I will not conceal my errour concurred in the same opinion and for that time said no more nor can I tell you by what hints I was moved to return to ruminate with my self upon this businesse and in the end came to discover my simplicity although excusable in admitting that for true which is most false false I say that the great agitation of the basket or round top in comparison of the small one below at the partners of the Mast should render the use of the Telescope more difficult in finding out the object SALV I should have accompanied the Mariners and your self at the beginning SIMP And so should I have done and still do nor can I believe if I should think of it an hundred years that I could understand it otherwise SAGR. I may then it seems for once prove a Master to you both And because the proceeding by interrogatories doth in my opinion much dilucidate things besides the pleasure which it affords of confounding our companion forcing from him that which he thought he knew not I will make use of that artifice And first I suppose that the Ship Gally or other Vessel which we would discover is a great way off that is four six ten or twenty miles for that to kenne those neer at hand there is no need of these Glasses consequently the Telescope may at such a distance of four or six miles conveniently discover the whole Vessel a muchgreater bulk Now I demand what for species how many for number are the motions that are made upon the round top depending on the fluctuation of the Ship SALV We will suppose that the Ship goeth towards the East First in a calme Sea it would have no other motion than this of progression but adding the undulation of the Waves there shall result thence one which alternately hoysting and lowering the poop and prow maketh the round top to lean forwards and backwards other waves driving the vessel sidewayes bow the Mast to the Starboard and Larboard others may bring the ship somewhat abovt and bear her away by the Misne from East one while towards the Northeast another while toward the Southeast others bearing her up by the Carine may make her onely to rise and fall and in sum these motions are for species two one that changeth the direction of the Telescope angularly the other lineally without changing angle that is alwayes keeping the tube of the Instrument parallel to its self SAGR. Tell me in the next place if we having first directed the Telescope yonder away towards the Tower of Burano six miles from hence do turn it angularly to the right hand or to the left or else upwards or downwards but a straws breadth what effect shall it have upon us touching the finding out of the said tower SALV It would make us immediately lose sight of it for such a declination though small here may import there hundreds and thousands of yards SAGR. But if without changing the angle keeping the tube alwayes parallel to it self we should transfer it ten or twelve yards farther off to the right or left hand upwards or downwards what alteration would it make as to the Tower SALV The change would be absolutely undiscernable for that the spaces here and there being contained between parallel rayes the mutations made here and there ought to be equal and because the space which the Instrument discovers yonder is capable of many of those Towers therefore we shall not lose sight of it SAGR. Returning now to the Ship we may undoubtedly affirm that the Telescope moving to the right or left upwards or downwards and also forwards or backwards ten or fifteen fathom keeping it all the while parallel to its self the visive ray cannot stray from the point observed in the object more than those fifteen fathom and because in a distance of eight or ten miles the Instrument takes in a much greater space than the Gally or other Vessel kenn'd therefore that small mutation shall not make me lose sight of her The impediment therefore and the cause of losing the object cannot befall us unlesse upon the mutation made angularly since that Telescopes transportation higher or lower to the right or to
the left by the agitation of the ship cannot import any great number of fathomes Now suppose that you had two Telescopes fixed one at the Partners close by the Deck and the other at the round top nay at the main top or main top-gallant top where you hang forth the Pennon or streamer and that they be both directed to the Vessel that is ten miles off tell me whether you believe that any agitation of the ship inclination of the Mast can make greater changes as to the angle in the higher tube than in the lower One wave arising the prow will make the main top give back fifteen or twenty fathom more than the foot of the Mast and it shall carry the upper tube along with it so greata space the lower it may be not a palm but the angle shall change in one Instrument aswell as in the other and likewise a side-billow shall bear the higher tube an hundred times as far to the Larboard or Starboard as it will the other below but the angles change not at all or else alter both alike But the mutation to the right hand or left forwards or backwards upwards or downwards bringeth no sensible impediment in the kenning of objects remote though the alteration of the angle maketh great change therein Therefore it must of necessity be confessed that the use of the Telescope on the round top is no more difficult than upon the Deck at the Partners seeing that the angular mutations are alike in both places SALV How much circumspection is there to be used in affirming or denying a proposition I say again thar hearing it resolutely affirmed that there is a greater motion made on the Masts top than at its partners every one will perswade himself that the use of the Telescope is much more difficult above than below And thus also I will excuse those Philosophers who grow impatient and fly out into passion against such as will not grant them that that Cannon bullet which they cleerly see to fall in a right line perpendicularly doth absolutely move in that manner but will have its motion to be by an arch and also very much inclined and transversal but let us leave them in these labyrinths and let us hear the other objections that our Author in hand brings against Copernicus SIMP The Author goeth on to demonstrate that in the Doctrine of Copernicus it is requisite to deny the Senses and the greatest Sensations as for instance it would be if we that feel the respirations of a gentle gale should not feel the impulse of a perpetual winde that beateth upon us with a velocity that runs more than 2529 miles an hour for so much is the space that the centre of the Earth in its annual motion passeth in an hour upon the circumference of the grand Orb as he diligently calculates and because as he saith by the judgment of Copernicus Cum terra movetur circumpositus aër motus tamen ejus velocior licet ac rapidior celerrimo quocunque vento à nobis non sentiretur sed summa tum tranquilitas reputaretur nisi alius motus accederet Quid est verò decipi sensum nisi haec esset deceptio Which I make to speak to this sense The circumposed air is moved with the Earth yet its motion although more speedy and rapid than the swiftest wind whatsoever would not be perceived by us but then would be thought a great tranquillity unlesse some other motion should happen what then is the deception of the sense if this be not SALV It must needs be that this Philosopher thinketh that that Earth which Copernicus maketh to turn round together with the ambient air along the circumference of the great Orb is not that whereon we inhabit but some other separated from this for that this of ours carrieth us also along with it with the same velocity as also the circumjacent air And what beating of the air can we feel when we fly vvith equal speed from that vvhich should accost us This Gentleman forgot that vve no less than the Earth and air are carried about and that consequently vve are alvvays touch'd by one and the same part of the air vvhich yet doth not make us feel it SIMP But I rather think that he did not so think hear the vvords vvhich immediatey follovv Praeterea nos quoque rotamur ex circumductione terrae c. SALV Now I can no longer help nor excuse him do you plead for him and bring him off Simplicius SIMP I cannot thus upon the sudden think of an excuse that pleaseth me SALV Go to take this whole night to think on it and defend him to morrow in the mean time let us hear some other of his objections SIMP He prosecuteth the same Objection shewing that in the way of Copernicus a man must deny his own senses For that this principle whereby we turn round with the Earth either is intrinsick to us or external that is a rapture of that Earth and if it be this second we not feeling any such rapture it must be confessed that the sense of feeling doth not feel its own object touching it nor its impression on the sensible part but if the principle be intrinsecal we shall not perceive a local motion that is derived from our selves and we shall never discover a propension perpetually annexed to our selves SALV So that the instance of this Philosopher lays its stress upon this that whether the principle by which we move round with the Earth be either extern or intern yet however we must perceive it and not perceiving it it is neither the one nor the other and therefore we move not nor consequently the Earth Now I say that it may be both ways and yet we not perceive the same And that it may be external the experiment of the boat superabundantly satisfieth me I say superabundantly because it being in our power at all times to make it move and also to make it stand still and with great exactness to make observation whether by some diversity that may be comprehended by the sense of feeling we can come to know whether it moveth or no seeing that as yet no such science is obtained Will it then be any matter of wonder if the same accident is unknown to us on the Earth the which may have carried us about perpetually and we without our being ever able to experiment its rest You Simplicius as I believe have gone by boat many times to Padoua and if you will confess the truth you never felt in your self the participation of that motion unless when the boat running a-ground or encountring some obstacle did stop and that you with the other Passengers being taken on a sudden were with danger over-set It would be necessary that the Terrestrial Globe should meet with some rub that might arrest it for I assure you that then you would discern the impulse residing in you when it