Naturalists do not admit what Mr. Hobbs supposes a few lines before that That which is at rest cannot be mov'd but by a moved and contiguous Movent For they think Motion or at least conatus ad motum an unlooseable Property congenit to Matter And by the way whatever exceptions I have to this Opinion yet I am not satisfied with that Principle of Mr. Hobbs though it be the Fundamental one of his Philosophy unless it be more warily propos'd For to assert universally and without exception as he does in his Elements that nothing can be moved but by a Body contiguous and moved I do not take to be true nor consistent with his other Assumptions This I elswhere in a Discourse against another than Mr. Hobbs about the Christian Religion prove more at large But now it will suffice to represent that Mr. Hobbs not onely admitting but making use in his Philosophy of the Creation of the World either he must allow that Motion is Natural to some if not all Parts of Matter or that God put them into a Motion not included in their Nature From which it will necessarily follow that at least some Bodies may have Motion though it be not given them by any Body contiguous and moved as an attentive considerer mâ—y easily discern But to return to the Cause of Springs Secondly whereas Mr. Hobbs assumes that the Parts of the Ambient have no endeavour which contributes to their Compression or Extention nor to the setting of them at Liberty or Restitution He says this indeed But does not go about to prove it And I should the less have made this precarious Assertion because that after the celebrated Des Cartes himself the Cartesian Philosophers generally ascribed the Motion of Restitution to the passage of a subtile Ethereal Substance and an AEther Mr. Hobbs also admits through the Pores of the Springy Body which striving to obtain its wonted Freedom of passage restores them to the shape and bigness from which they were forced Nay I shall have occasion to shew anon that Mr. Hobbs himself whatever he say in this place does elsewhere ascribe a Motion of their own to multitudes of Terrestrial Corpuscles And I might add that elsewhere he speaks of the re-kindling of the Fire taken out of the Receiver after this manner Quanquam vis illius motus in Recipiente ut loquimini evacuato diminuta sit oppressa ab Aëris intus commoti consistentia non tamen extinguitur propterealevata oppressione satis habebit virium ad excitandum phantasiam lucis quanquan debiliorem But I shall rather subjoyn That yet Thirdly I do not think it improbable what the Learned Gassendus had taught and what Mr. Hobbs here teaches that the Restitution of bent Springs may proceed from a certain Endeavour or Motion in their internal Parts left from the time of their Compression or Extension which when the Impediment is remov'd makes every Part resume its former place and thereby makes the Whole restore it self But this notwithstanding I fear'd others might be as Inquisitive as my self and might expect from him that would undertake to settle a general Theory of the Motion of Restitution the clear and distinct Explication of several Phaenomena that I had met with which are not touch'd nor perhaps were some of them thought upon by Mr. Hobbs As first why such a deâ—â—rminate Temper of Iron and Steel is requisite to make it Elastical so that if after having been hardned and gradually heated it be suddenly cool'd at an inconvenient point of time it will be brittle and fit to make Gravers and other rigid Tools not Springs Next why Bows and other Elastical Bodies if they be kept too long bent lose in process of time almost all their Elastical Power and continue crooked Thirdly why not onely divers solid Bodies as well as Lead and Gold which before tryal one would think as likely as many Springy ones to have their Parts put into a due Motion by the force that bends them should be devoid of an Elastical Power Fourthly what kind of Motion and what kind of Texture it is by virtue whereof the Parts of a Body being for a very short time put into Motion do some Months perhaps some Years retain in great part a smart Motion without in so long a time communicating it to the Ambient Bodies to some or other of which multitudes of them are perpetually contiguous and thereby losing it themselves Why upon such a bare and inartificial change made in the Texture of a Body as is scarce at all discernable to the Eye it should acquire a strong Spring that it had not before as I have try'd upon Silver and Copper which though flexible before they were hammer'd yet being beaten into thin Plates obtain'd a notable Spring And why which may seem more strange upon another light change of Texture the acquired Spring may presently be lost again as I have try'd in Silver that Chymists teach us loses nothing in the fire which having by being hammer'd acquir'd a strong Spring we have presently made flexible again as before by only heating it red-hot without so much as melting it which argues that in Springs Texture is as well to be considered as Motion To these I might add other Particulars that I had either made or observ'd and mention in another Treatise concerning Springs all which Phaenomena perhaps every one that has read what we have lately recited out of Mr. Hobbs will not presently be able satisfactorily to explicate So that I hope the equitable Reader will not think it a fault that contenting my self to propose the two Explications of Springs I saw most lik'd among the Curious to which I should have added Mr. Hobbs's if I had found it as much esteemed I declin'd engaging my self in Controversies about the Origine of Motion and such other high Speculations as had my Abilities enabled me neither my Design exacted nor my leasure permitted that I should prosecute And though Mr. Hobbs be pleased to speak thus of his Notion concerning the Restitution of Bodies Sine qua Hypothest quantuscunque labor ars sumptus ad rerum naturalium invisibiles causas inveniendas adhibetur frustra erit Yet whether that bold Assertion should passe for an Argument for an Hyperbole or for a Complement to himself I am content to let the Reader judge Fourthly Mr Hobbs in divers passages wherein he disputes against me seems to have misapprehended my Notion of the Air. For when I say that the Air has Gravity and an Elastical Power or that the Air is in great part pump'd out of the Receiver 't is plain enough that I take the Air in the obvious Acception of the word for part of the Atmosphere which we breath and wherein we move Nor do I find that any other of my Readers do otherwise understand me But Mr. Hobbs seems to think he has sufficiently confuted me if in some cases he have prov'd which whether he
eorundem superficiali vel etiam intricatione Not again to say any thing to his durum primum I confess I do not see how the motus circularis simplex should need to be superadded to the Contact or Intrication of the cohering firm Corpuscles to procure a Cohesion to which'tis needless and which in divers cases may be rather hindered than furthered by it The third thing that Mr. Hobbs alledges is not so much a confirmation of his own Doctrine as an Objection as he seems to think against that of his Adversaries For Si supponamus sayes he presently after his last-recited words cum illis duritiei causam esse magnitudinem aut crassitiem partium quam rationem reddere poterimus cur durior vel firmior sit aqua congelata quam est eadem aqua ante congelationem But it may easily be replyed That we make not the bigness or grosness of the parts of a body the onely or chief cause of its hardness but their rest by one another which the parts of frozen water have whereas those of unfrozen water have it not but are in a state of Fluidity and consequently not of Firmness Which may be illustrated by what I elsewhere relate of pure Oyle of Aniseeds and a substance I distilled out of Benzoin both which bodies were sometimes fluid and sometimes consistent as the greater or lesser warmth of the Air kept their parts in a due motion or suffered them to rest But in exchange of these few unconcluding arguments which are all that Mr. Hobbs alledges to countenance his Paradox how many Experiments and Reasons mightwe transcribe out of our History of Fluidity and Firmness in favour of the contrary Truth And as Critical as Mr. Hobbs appears in laying down the requisites of a good Hypothesis I must make bold to the two conditions he mentions pag. 11. Vt sit conceptibilis idest non absurda which whether it be enough I now dispute not Vt ab ea concessa inferri possit Phaenomeni necessitas to adde a third namely That it be not inconsistent with any other Truth or Phaenomenon of Nature Which third condition whether divers of Mr. Hobbs's Hypotheses which himself in this place calls mirandae do not want we have in part already considered in the Treatise to which this is an Appendix and as I newly intimated I might further shew as to his Notion of Fluidity and Firmness if I would here repeat all the Experiments mentioned in my History of them though they be not all that I have made ready to the same purpose against another opportunity but partly weariness and partly a natural unwillingness to repeat induces me rather to refer my Reader thither Which when I do I do not forget that Mr. Hobbs appears offended at me and others for troubling our selves to make un-obvious Experiments But that I may not repeat what in divers Treatises I represent concerning the Usefulness of such Experiments I shall now onely oppose to the Authority of Mr. Hobbs in this Dialogue wherein he has been pleased to chuse those he calls the Experimentarian Philosophers for his Adversaries the Authority and Reason of the same Mr. Hobbs in another Dialogue published but the year before where one of his two Discoursers having said Qui corpora corporibus admovendo nova mirabilia ostendunt Naturae opera mirum in modum incendunt animos hominum amore Philosophiae ad causas investigandas non parum instigant eoque nomine laude digni sunt the other confirms it by adding It a est nam historiam Naturalem sine qua scientia Naturalis frustra quaeritur locupletant And howsoever Mr. Hobbs needed not have recourse to such Experiments as he would be thought to disapprove I mean Elaborate ones to discern that his Notions do not over-well agree with the Phaenomena For if there be not a various motion in the small parts of Water and such liquors whence is it that a lump of common Salt being thrown into a pot of water is there dissolved into minute bodies whereof many are carried to the very top of the water and are so exquisitely diffused and mingled with the liquor that each least drop of it contains numbers of Saline Corpuscles And if motion be the cause rather of hardness than fluidity how comes it to pass that in frosty weather Ice is by heat which Mr. Hobbs will not deny to be motion or an effect of it turned from a hard to a fluid body And that Metals as Gold and Silver c. whilst they are either cold or exposed but to a moderate heat are firm and consistent bodies and by a violent heat which does manifestly give their parts a various and vehement agitation as appears by their sudden dissipating of Spittle Greace and far more stable bodies cast upon them into smoak are put into a fluidity which upon their removal from the fire they quickly exchange for firmness But since the want of more to say would not in haste put a Period to this Discourse I am content to let my Haste break it off especially since after I have thus examined what Mr. Hobbs teaches concerning Fluidity and Firmness either here or in that Section of his Elements where he pretends to define them I think I need not fear that a Doctrine which I have perhaps with some care endeavoured to establish for the main upon Experiments should be overthrown by Opinions whose grounds are but such as we have already seen and in pleading for which the Author is pleased not onely to leave almost all my Arguments untouch'd but not so much as to offer at explicating by his Principles any of those numerous and important Phaenomena of Fluidity and Firmness delivered in the Treatise he opposes And now leaving Mr. Hobbs to apply my self to the Reader I have to the things hitherto discourst but this one thing to adde concerning them That as little cause as Mr. Hobbs has hitherto given me to distrust what I have written of Fluidity and Firmness yet I am not now more confident of my Conjectures than I was when toward the end of the Preface to the History of these two Qualities I spoke diffidently enough of the Theorical part of that Treatise And I freely confess that the great difficulty of things and the little abilities I find my self furnisht with to surmount it do often in general beget in me a great distrust even of things whereof my Adversaries Objections give me not any FINIS The Citations English'd PAg. 12. Quanquam vis c. Although the force of that motion in the evacuated Receiver be diminished being opprest by the consistence of the Air moved within yet it is not extinguished and therefore that oppression being taken off will have strength enough to excite an appearance of light though somewhat weaker than ordinary p. 13 14. Sine c. Without which Hypothesis let never so much labour art cost be bestowed for the
such a length that by its descent it may give passage to the Air through the circumferences of the holes Nor can the Air driven off by the water going out find any other place besides that which the water leaves p. 69. Qui per c. He that sucks water into his mouth by a Pipe first sucks up the Air between whereby he removes the distended external Air which being removed the world being full it can have no place but by removing the next and so by continual pulsion the water is at length driven into the Pipe and doth fucceed the Air which is suckt out p. 72. Id vero c. But that is impossible For in a Siphon unless both legs are filled with water the water will not ascend out of the Bason The cause of its ascent into that cloth is the motion of the earthy Atoms which are near the water I say the simple circular motion communicated to the Air in which they move which Atoms striking the water beat it up into the woolly matter which beating of them against the cloth makes it more and more moist till it becomes all over wet And when it is so c. p. 73. A. Fateris c. You confess then that your Collegiates have as yet in nothing advanced the knowledge of natural causes but that one of them hath found out an Engine in which there may be such a motion of the Air excited that the parts of the Sphere may together every way tend unto the Centre and that the Hypotheses of Mr. Hobbs before probable enough may be thence made more probable B. Right I am not ashamed to confess it for it is somewhat to arrive so far if we can make no further progress A. Why so far To what end such preparation and charge for Engines difficult to be made to make no further discovery than Mr. Hobbs had made before you Why did you not rather begin where he ended Why did you not use the Principles he had laid and when Aristotle had rightly said That without the knowledge of Motion there is no knowledge of Nature how durst you take such a task upon your selves Ibid. Est c. Thus to have made an entrance though we miss Of further progress some performance is p. 75. But most of us distinguish the nature of fluid from that which is not fluid by the greatness of the parts of which any body consists and is made up with Wherefore we do not onely look upon Air Water and all Liquors but upon Ashes also and Dust as fluid bodies And we deny not that fluid things may be made of things not fluid for we do not digest the Notion of infinite Divisibility A. Infinite Division cannot be conceived but infinite Divisibility may easily I on the contrary do not understand the distinction of Fluids and not Fluids which you take from the greatness of the parts could I digest this I must say the ruines of shattered rubbish stones that lye in Pauls were fluid But if those ruines cannot be called fluid because the stones are too big define me the bigness that the parts of a ruin'd wall must have that they may be called fluid But you that cannot understand infinite Divisibility tell me what you think to be the cause why I should think it more hard for Almighty God to create a fluid body less than any Atom proposed that its parts might actually flow than to create the Ocean Therefore you make me despair of any fruit of your meeting by saying that they think Air Water and other fluids consist of Non-fluids as if a wall that began to fall and be ruinous were called by them a fluid body If they may speak so every thing is fluid for even Marble it self may be broken into parts less than any Atom imagin'd by Epicurus p. 79. Ruina c. The ruines that lye in Pauls Church might be called fluid Ibid. Si sic c. If they may so speak there is nothing but is fluid for even Marble may be beaten into parts less than any Epicurean Atom p. 80. Divisio c. Division that is infinite cannot be conceived Divisibility may easily p. 81 82. Quia corpuscula c. But the Corpuscles such as are the Atoms supposed by Lucretius and also by Mr. Hobbs being hard before might be easily compacted by any of the mention'd causes so that it is not to be doubted but that the whole to be made of those Corpuscles will be hard Ibid. Si dura c. If hard bodies are made out of parts originally hard why are not fluid bodies made of parts originally fluid Could great fluids as the AEther be created and could not small ones He that first made a body hard or fluid could if he would have made it greater or less than any other proposed body Now if a fluid body be made of parts not fluid as you speak and hard bodies onely from hard parts doth it not follow that nothing neither fluid nor hard is made of original fluids p. 84. B. Quaenam c. What are the principles of Fluidity and Firmness A. Of Fluidity nothing but Rest of Firmness Motion such as is fit to produce that effect By Rest I understand the rest of two parts one with another when they each touch but neither press one another For entire bodies of fluids may be in motion their fluidity abiding and hard bodies be at rest although their parts be in motion p. 85. Atque binc c. And hence it is manifest that there is a great compression in the Air so moved and shut up namely so great as that force by which it was driven in was able to make and also that from so great compression some degree of consistence must be made though less than that of the consistence of water Now if in all the same Particles of Air besides the motion by which one presses another there was also the simple circular motion and that vehement enough it would be almost impossible any one of them should be moved from its little circle but that the other Particles resisting the whole would be pressed together that is become hard For that is hard of which no part gives place but upon the motion of the whole You see therefore that hardness may be made in a most fluid body by this simple circular motion of Particles which was before imparted to them by two contrary motions p. 86. Atque talis c. And such indeed may be the cause of the Durum primum or first hard body But of the second that is of the cohesion of two of these first hard bodies the cause may be the very same simple circular motion conjoyned with their superficial contact or perhaps their being one with another intricated Ibid. Si supponamus c. If we suppose with them that the cause of hardness is the greatness or thickness of the parts what reason can we give why congealed water
should be harder or firmer than the same water is before such congelation p. 87. Ut sit c. That it be conceivable that is not absurd and that from its being granted the necessity of the Phaenomenon may be inferr'd p. 88. Qui c. They which putting bodies to bodies shew the new and admirable works of Nature do wonderfully inflame the minds of men with the love of Philosophy and do not a little instigate them unto the search of Causes and on that account are worthy of commendation True for they enrich Natural History without which Natural Science is in vain sought for A Summary of the Contents of the several Chapters CHAP. I. THe occasion and scope of the present Treatise Reasons why Mr. Hobbs might have employed himself otherwise and have spared this Discourse p. 2. Why the Author would have been contented he had done so ibid. Why he now undertakes the Reply p. 3. CHAP. II. Of some mistakes of Mr. Hobbs touching matters of Fact and the Authors Doctrine That he mistakes in ascribing the Explications and Experiments in the Physico-Mechanical Treatise of the Society at Gresham College p. 3. the Experiments having been seen done long and the book published before the Society began c. p. 4. That the Experiments were not devised nor employed to prove a Vacuum Ibid. Whether Mr. Hobbs by the Experiment of the Gardeners Watering-pot demonstrates that there can be no Vacuum p. 5. That if the Watering-pot were tall enough the water would run out with unstopping the upper Orifice prov'd by M. Paschal's Experiment p. 6. The way of Argument on both sides compared p. 7 8. Why the Author did not assign the cause of Springs p. 9. That Mr. Hobbs his account of Springs is imperfect and that he has not solved the Phaenomena of them p. 10 11 12 13. That he mistook the Authors notion of the Air p. 14. 15. CHAP. III. Wherein the Weight and Spring of the Air are asserted against Mr. Hobbs Several Experiments recited that prove the real Weight of the Air p. 16 17. Mr. Hobbs's Objections against the Experiment of the heaviness of a blown Bladder p. 17 18. answered p. 19. The Spring of the Air asserted from Mr. Hobbs's concessions p. 20 21 The same asserted by particular Experiments p. 22 23. Mr. Hobbs his answer to that of the Bladder considered p. 23 24. Experiments of the Spring of the Air not comprest p. 25. CHAP. IV. Wherein Mr. Hobbs his principal Explications of the Authors Phaenomena are examined What things Mr. Hobbs takes for granted p. 26. His Hypothesis considered of the simple circular motion whether it be not precariously ascribed to aqueous and earthy Particles p. 27 28. Whether in the exhaustion of the Cylinder any Vacuum be produced p. 29 30 31. Experiments to prove that the Glass is in great part devoid of common Air p. 31 32. Whether a purer sort of Air may unperceived dive under Water to pass into the Receiver betwixt the Cylinder and the Suker p. 33 34. That the Cartesian way of explicating this Phaenomenon in favour of the Plenists is more plausible than Mr. Hobbs's p. 35. Whether the place deserted by the suspended Mercury in the Torricellian Experiment be empty or full of Air p. 37 38. Mr. Hobbs's Explication of that Experiment of Mr. Boyle in which the Air impells up the Sucker together with above 100. pound weight p. 39 40. The Examination of this Explication p. 41 42. CHAP. V. In which divers scatter'd Explications and other passages in Mr. Hobbs's Dialogue are examined His Explications why water without visible force ascends in a slender Pipe considered p. 44 45. Why the stopple of the Cover of the exhausted Receiver so much gravitates considered p. 46. His Explication and the Authors why in the exhausting of the Receiver water let down into it boyles as it were or bubbles there viewed and compared p. 47 48 Whether the Phaenomenon of this water bubbling in the Receiver be an evidence that there is no vacuity in the Receiver p. 49 50. Whether Animals in the exhausted Receiver dye for want of Air or for the causes assigned by Mr. Hobbs p. 51 52. That the Author asserts not the proof of a Vacuum or Plenum to depend on the Hypothesis of the Spring of the Air p. 53. That the Air in the exhausted Receiver is not thicker but thinner not heavier but lighter proved by Experiments p. 54 55. The Epicurean Hypothesis of fire and the effects of the Sun-beams through Burning-glasses p. 57. Whether he deserves a censure that calls kindled coals fire p. 58. CHAP. VI. Wherein other passages of Mr. Hobbs's Dialogue that concern the Author are examined That the Experiments of the Needle 's motion in the exhausted Receiver and of sounds being audible and objects visible there are reconcilable to the doctrine of the Atomists p. 59. Whether from the cohesion of two Marbles the non existence of a Vacuum follows p. 60 61. How the lower Marble is upheld p. 62 63. The power of the oblique pressure of the Air to these effects illustrated by Experiments p. 64. Whether the throwing up of water in the Glass fountains invented by Vincenzo Vincenti of Urbin can be explicated by the Spring of the Air p. 67 68. Mr Hobbs's Explication of the cause of waters being suspended in a Gardeners Watering-pot examin'd p. 69. An Experiment purposely devised to shew that both Vacuists and Plenists should admit an Elastical power in the Air p. 70 71. Mr. Hobbs's correction of the Authors discourse about the ascension of water in Siphons and Filtres animadverted p. 72. Some unhandsom passages and such as shew the unequal estimation Mr. Hobbs has of his own and others preformances in Philosophy p. 73 74. What parts of Mr. Hobbs's Treatise and why past by without censure by the Author p. 75. CHAP. VII Being an Appendix to the past Discourse Wherein is examined what Mr. Hobbs teaches concerning Fluidity and Firmness Mr. Hobbs mistakes and so misreports the Authors Doctrine of the cause of Fluidity p. 77. His Animadversions on the Doctrine considered p. 78 79. Whether fluid bodies are made from parts originally fluid or from small Solids in motion c. p. 79 80 81. Mr. Hobbs's Theory of Fluidity and Firmness examined p. 81 82 c. What influence therein his simple circular motion may have considered p. 82 83. That there is a third requisite of a good Hypothesis viz. That it be not inconsistent with any Truth or Phaenomenon of Nature p. 84. That Mr Hobbs his Hypothesis wants this requisite proved by references p. 85. By instances out of ordinary not elaborate Experiments p. 86. The Conclusion to the Reader p. 88. FINIS A CATALOGUE Of all the PHILOSOPHICAL WORKS Published by our AUTHOR * NEW Physico-mechanical Experiments concerning the Weight and Spring of the Air published in English Anno Dom. 1660. * A Continuation of them Part I. 1669. * The Defence of the
a digression 90 The 23 Experiment containing a farther enquiry touching Bubbles made with common and distill'd Water 91 The 24 Experiment wherein the enquiry is prosccuted with other Liquors as with Sallet Oyl Oyl of Turpentine a Solution of Tartar Spirit of Vinegar Red-Wine Milk Hens Eggs Spirit of Urine Spirit of Wine and Water Spirit of Wine 94 c. The wonderfull expansion of the Spirit of Wine 97 The 25 Experiment touching the expansion and gravity of the Air under Water 98 c. The 26 Experiment touching the Vibrations of a Pendulum 102 c. The 27 Experiment touching the propagation of sound and the Author's intention of trying some other Experiments for the further elucidation thereof 103 The 28 Experiment touching the sudden eruption of Bubbles from the Water when the Air 's pressure was speedily remov'd 108 The 29 Experiment touching the cause of the ascent of Fumes and Vapors wherein't is prov'd from the several motions which the Fumes of a strange smoking Liquor of the Author's were observ'd to have in the Receiver upon the exsuction of the Air that the reason of their ascent proceeds from the gravity of the ambient Air and not from any positive levity of their own 110 c. The 30 Experiment concerning the nature of a fluid Body illustrated by the example of smoke which in several circumstances seems very much to resemble the property of a fluid Body 113. A conjecture of the cause of the Sun's undulation 115 The 31 Experiment concerning the Phaenomena of two flat Marbles exactly plain'd and wrought together and the true reason thereof The Author's intention for the further prosecution thereof and what hindred him the reason why the under Marble did not fall from the upper being only conjoyn'd with Spirit of Wine when the Receiver was evacuated And a notable relation concerning the cohesion of flat Bodies 116 c. The 32 Experiment touching the forcible pressure of the Air against the outward Superficies of a Valve fasten'd upon the Stop-cock of the Receiver The Diameter of it and the weight it sustain'd 118 c. The 33 Experiment touching the great pressure of the Air against the under Superficies of the Sucker 120 c. what weight was requisite to depress it and what weight it would lift and carry up with it 121 c. What improvement and use there may be made of this Experiment ib. A Discourse touching the nature of Suction proving that Suga vacui is not the adequate cause thereof 123 c. The 34 Experiment containing several attempts for the weighing of light Bodies in the exhausted Receiver 131 c. The 35 Experiment touching the cause of a Filtration and the rising of mater in Siphons 133 c. A relation of a new kind of Siphon of the Author's upon the occasion of trying the Experiment lately observ'd by some French-men and further improv'd by himself and some conjectures touching the cause of the exhibited Phaenomena 136 c. The 36 Experiment touching the weighing of a parcel of Air in the exhausted Vessel and some other Observations for the explication thereof 138 c. An accidental Experiment tending to the further confirmation of the Author's Reflexions upon the first Experiment with a digressive observation noting the subtile penetrancy of some Spirits to exceed by far that of the Air 140 c. and some other Experiments to shew the difficulty of the ingress of the Air into the pores or holes of some Bodies into which water will readily insinuate it self with a conjecture at the cause thereof 142. The Author returns to the prosecution of the inquiry after the gravity of the Air But first upon the occasion of the tenacity of a thin Bubble of Glass sets down his thoughts concerning the strange exuperancy of strength in Air agitated by heat above what the same hath unagitated and then proceeds to the examination of the weight of the Air by an AEolipile and compares the result thereof with that of Mersennus 143 144 c. The Opinions and Experiments of divers Authors and some of his own touching the proportion of weight betwixt Water and Air are compar'd and examin'd by the Author 145. The result thereof ibid. Mersennus his Observation reconciled with that of the Author and the proportion between the gravity of Water and Air about London 146 c. After the recital of the Opinions of several Writers touching the proportion of gravity between Water and Quick-silver the Author sets down his own trials made several ways together with his conclusion therefrom 147 c. The use he makes of this inquiry for the ghessing at the height of the Atmosphere 148. what other Experiments are requisite to the determination thereof 149 The 37 Experiment touching the strange and odd Phaenomenon of the sudden flashes of light in the cavity of the Receiver the several circumstances and difficulties of it with some attempts towards the rendring a reason thereof 153 c. The difficulty of so doing farther shown from the consideration of the various changes of Air which do not immediately fall under our senses This last proposition prov'd by several Observations 156 157 The 38 Experiment touching the freezing of Water A problem concerning the great force wherewith a freezing Liquor extends it self proposed upon the consideration of divers admirable effects wrought thereby 162 The 39 Experiment containing an inquisition after the temperature of the substance that remained in the cavity of the Receiver after the Air was well exhausted The relation of a Phaenomenon seeming to proceed from the swelling of the Glass with an advertisement concerning the pliableness of Glass in small pieces 164 The 40 Experiment touching the difficulty that occurred in making trial whether rarefied Air were able to sustain flying Insects 166 The 41 Experiment exhibiting several trials touching the respiration of divers sorts of Animals included in the Receiver 167 c. with a digression containing some doubts touching Respiration wherein are delivered several Experiments relating thereunto 171 The 42 Experiment touching the differing operation of corrosive Liquors in the emptied Receiver and in the open Air. 196 The 43 Experiment touching the spontaneous Ebullition of warm Liquors in the exhausted Receiver 198 The Conclusion 201 TO THE LORD of DUNGARVAN My Honored and Dear NEPHEW My Dear Lord REceiving in your last from Paris a desire that I would adde some more Experiments to those I formerly sent You over I could not be so much your Servant as I am without looking upon that Desire as a Command and consequently without thinking my self obliged to consider by what sort of Experiments it might the most acceptably be obey'd And at the same time perceiving by Letters from some other Ingenious Persons at Paris that several of the Virtuosi there were very intent upon the examination of the Interest of the Air in hindring the descent of the Quick-silver in the famous Experiment touching a Vacuum I thought I could not
that lean upon them And as for the easie yielding of the Air to the Bodies that move in it if we consider that the Corpuscles whereof it consists though of a springy nature are yet so very small as to make up which 't is manifest they do a fluid Body it will not be difficult to conceive that in the Air as in other Bodies that are fluid the little Bodies it consists of are in an almost restless motion whereby they become as we have more fully discoursed in another Treatise very much disposed to yield to other Bodies or easie to be displac'd by them and that the same Corpuscles are likewise so variously mov'd as they are intire Corpuscles that if some strive to push a Body plac'd among them towards the right hand for instance others whose motion hath an opposite determination as strongly thrust the same Body towards the left whereby neither of them proves able to move it out of its place the pressure on all hands being reduced as it were to an AEquilibrium So that the Corpuscles of the Air must be as well sometimes considered under the notion of little Springs which remaining bent are in their entire bulk transported from place to place as under the notion of Springs displaying themselves whose parts fly abroad whilst as to their entire bulk they scarce change place As the two ends of a Bow shot off fly from one another whereas the Bow it self may be held fast in the Archer's hand and that it is the equal pressure of the Air on all sides upon the Bodies that are in it which causeth the easie Cession of its parts may be argu'd from hence That if by the help of our Engine the Air be but in great part though not totally drawn away from one side of a Body without being drawn away from the other he that shall think to move that Body to and fro as easily as before will find himself much mistaken In verification of which we will to divert your Lordship a little mention here a Phaenomenon of our Engine which even to divers ingenious persons hath at first sight seem'd very wonderfull EXPERIMENT II. THe thing that is wont to be admired and which may pass for our second experiment is this That if when the Receiver is almost empty a By-stander be desired to lift up the brass Key formerly described as a stopple in the brass Cover he will find it a difficult thing to do so if the Vessel be well exhausted and even when but a moderate quantity of Air hath been drawn out he will when he hath lifted it up a little so that it is somewhat loose from the sides of the lip or socket which with the help of a little oyl it exactly filled before he will I say find it so difficult to be lifted up that he will imagine there is some great weight fastned to the bottom of it And if as sometimes hath been done for merriment onely a Bladder be tied to it it is pleasant to see how men will marvail that so light a Body filled at most but with Air should so forcibly draw down their hand as if it were fill'd with some very ponderous thing Whereas the cause of this pretty Phaenomenon seems plainly enough to be only this That the Air in the Receiver being very much dilated its Spring must be very much weakn'd and consequently it can but faintly press up the lower end of the stopple whereas the Spring of the external Air being no way debilitated he that a little lifts up the stopple must with his hand support a pressure equal to the disproportion betwixt the force of the internal expanded Air and that of the Atmosphere incumbent upon the upper part of the same key or stopple And so men being unused to find any resistance in lifting things up from the free Air above them they are forward to conclude that that which depresseth their hands must needs be some weight though they know not where plac'd drawing beneath it And that we have not mis-assign'd the cause of this Phaenomenon seems evident enough by this That as Air is suffered by little and little to get into the Receiver the weight that a man fancieth his hand supports is manifestly felt to decrease more and more the internal Air by this recruit approaching more to an AEquilibrium with the external till at length the Receiver growing again full of Air the stopple may be lifted up without any difficulty at all By several other of the Experiments afforded us by our Engine the same notion of the great and equal pressure of the free Air upon the Bodies it environs might be here manifested but that we think it not so fit to anticipate such Experiments And therefore shall rather employ a few lines to clear up the difficulty touching this matter which we have observ'd to have troubled some even of the Philosophical and Mathematical Spectators of our Engine who have wonder'd that we should talk of the Air exquisitely shut up in our Receiver as if it were all one with the pressure of the Atmosphere whereas the thick and close body of the Glass wholly impervious to the Air doth manifestly keep the incumbent Pillar of the Atmosphere from pressing in the least upon the Air within the Glass which it can no where come to touch To elucidate a little this matter let us consider That if a man should take a fleece of Wooll and having first by compressing it in his hand reduc'd it into a narrower compass should nimbly convey and shut it close up into a Box just fit for it though the force of his hand would then no longer bend those numerous springy Bodies that compose the Fleece yet they would continue as strongly bent as before because the Box they are inclos'd in would as much resist their re-expanding of themselves as did the hand that put them in For thus we may conceive that the Air being shut up when its parts are bent by the whole weight of the incumbent Atmosphere though that weight can no longer lean upon it by reason it is kept off by the Glass yet the Corpuscles of the Air within that Glass continue as forcibly bent as they were before their inclusion because the sides of the Glass hinder them from displaying or stretching out themselves And if it be objected that this is unlikely because even Glass bubbles such as are wont to be blown at the flame of a Lamp exceeding thin and Hermetically seal'd will not break whereas it cannot be imagin'd that so thin a Prison of Glass could resist the Elastical force of all the included Air if that Air were so compress'd as we suppose It may be easily reply'd That the pressure of the inward Air against the Glass is countervail'd by the equal pressure of the outward against the same Glass And we see in bubbles that by reason of this an exceeding thin film of Water is often able for
Liquor might proceed from the agitation whereinto the exhaling and imprison'd Steams were put by that heat which is wont to result from that action of corrosive salts upon Metals we suffered both the Viol and the open-mouth'd Glass to remain as they were in a Window for three or four days and nights together but looking upon them several times during that while as well as at the expiration of it the whole cavity of the glass Bubble and most of its Neck seem'd to be possess'd by Air since by its spring it was able for so long to hinder the expell'd and ambient Liquor from regaining its former place And it was remarkable that just before we took the glass Bubble out of the other Glass upon the application of a warm hand to the convex part of the Bubble the imprison'd substance readily dilated it self like Air and broke through the Liquor in divers bubbles succeeding one another Having also another time try'd the like Experiment with a small Viol and with Nails dissolv'd in Aquafortis we found nothing incongruous to what we have now deliver'd And this Circumstance we observ'd that the newly generated Steams did not onely possess almost all the whole cavity of the Glass but divers times without the assistance of the heat of my hand broke away in large bubbles through the ambient Liquor into the open Air So that these Experiments with corrosive Liquors seem'd manifestly enough to prove though not that Air may be generated out of the Water yet that in general Air may be generated anew Lastly To the foregoing Arguments from Experience we might easily subjoyn the Authority of Aristotle and of his Followers the Schools who are known to have taught that Air and Water being symbolizing Elements in the quality of moisture are easily transmutable into one another But we shall rather to the foregoing Argument add this drawn from Reason That if as Leucippus Democritus Epicurus and others follow'd by divers modern Naturalists have taught that the difference of Bodies proceeds but from the various Magnitudes Figures Motions and Textures of the small parts they consist of all the qualities that make them differ being deducible from thence there appears no reason why the minute parts of Water and other Bodies may not be so agitated or connected as to deserve the name of Air. For if we allow the Cartesian Hypothesis according to which as we noted at the beginning of this Letter the Air may consist of any terrene or aqueous Corpuscles provided they be kept swimming in the interfluent Celestial Matter it is obvious that Air may be as often generated as Terrestrial Particles minute enough to be carried up and down by the Celestial Matter ascend into the Atmosphere And if we will have the Air to be a congeries of little slender Springs it seems not impossible though it be difficult that the small parts of divers Bodies may by a lucky concourse of causes be so connected as to constitute such little Springs since as we note in another Treatise Water in the Plants it nourisheth is usually contriv'd into springy Bodies and even the bare alter'd position and connexion of the parts of a Body may suffice to give it a Spring that it had not before as may be seen in a thin and flexible Plate of Silver unto which by some strokes of a Hammer you may give a Spring and by onely heating it red-hot you may make it again flexible as before These My Lord are some of the Considerations at present occurring to my thoughts by which it may be made probable that Air may be generated anew And though it be not impossible to propose Objections against these as well as against what hath been represented in favour of the contrary Doctrine yet having already almost tired my self and I fear more than almost tired Your Lordship with so troublesome an Enquiry after the nature of Bubbles I shall willingly leave Your Lordship to judge of the Arguments alledged on either side and I should scarce have ventur'd to entertain You so long concerning such empty things as the Bubbles which have occasioned all this Discourse but that I am willing to invite You to take notice with me of the obscurity of things or the dimness of our created Intellects which yet of late too many so far presume upon as either to deny or censure the Almighty and Omniscient Creator himself and to learn hence this Lesson That there are very many Things in Nature that we disdainfully overlook as obvious or despicable each of which would exercise our Understandings if not pose them too if we would but attentively enough consider it and not superficially contemplate but attempt satisfactorily to explicate the nature of it EXPERIMENT XXIII SInce the writing of the twenty first and twenty second Experiments and notwithstanding all that hath been on their occasion deliver'd concerning Bubbles we made some farther trials in prosecution of the same inquiry whereto they were designed We chose then amongst those Glasses which Chymists are wont to call Philosophical Eggs one that containing about nine Ounces of Water had a Neck of half an Inch in Diameter at the top and as we guest almost an Inch at the bottom which breadth we pitched upon for a reason that will by and by appear then filling it up with common Water to the height of about a Foot and an half so that the upper part remained empty we shut it into the Receiver and watch'd what would follow upon pumping which proved that a great part of the Air being drawn out the Bubbles began to discover themselves at the bottom and sides of the Glass and increasing as the Air was more and more drawn away they did from time to time ascend copiously enough to the top of the Water and there quickly break but by reason that the wideness of the Glass allow'd them free passage through the Water they did not appear as in the former Experiments to make it swell The Water scarce ever rising at all above the mark affixt to its upper surface when it was put in and upon the return permitted to the outward Air and consequently the shrinking in of the remaining bubbles the Water seem'd to have lost of his first extent by the avolation of the formerly interspers'd Air. Being willing likewise to try whether distilled Water were by having been divided into minute parts and then re-united more or less dispos'd to expand it self than Water not distill'd We took out of our Laboratory some carefully distill'd Rain-water and put about two Ounces of it into a round Glass-bubble with a very small Neck not exceeding the sixth part of an Inch in diameter which we filled half way to the top and then convey'd it into the Receiver the issue was that though we drew out more Air than ordinary yet there appeared not the least intumescence of the Water nor any ascending bubbles But suspecting that either the small quantity of the Water or
of the Pipe some Inches of water will remain suspended which 't is probable would not happen if the Air could get in to succeed it since if the hole were a little wider the Water would immediately subside And though it be true that if the Pipe be of the length of many Inches a great part of the Water will run down at the wider Orifice yet that seems to happen for some other reason than because the Air succeeds it at the upper and narrow Orifice since all the slender part of the Pipe and perhaps some Inches more will continue full of Water And on this occasion I remember that whereas it appears by our fifth Experiment That the Aërial Corpuscles except perhaps some that are extraordinarily fine will not pass thorow the Pores of a Lambs Bladder yet Particles of Water will as we have long since observ'd and as may be easily try'd by very closely tying a little Alcalizate Salt we us'd the Calx of Tartar made with Nitre in a fine Bladder and dipping the lower end of the Bladder in Water for if you hold it there for a competent while you will find that there will strain thorow the Pores of the Bladder Water enough to dissolve the Salt into a Liquor But I see I am slip'd into a Digression wherefore I will not examine whether the Experiment I have related proceeded from hence That the springy Texture of the Corpuscles of the Air makes them less apt to yield and accommodate themselves easily to the narrow Pores of Bodies than the more flexible Particles of Water or whether it may more probably be ascrib'd to some other Cause Nor will I stay to consider how far we may hence be assisted to ghess at the cause of the ascension of Water in the slender Pipes and Siphons formerly mention'd but will return to our Bubble and take notice That we thought fit also to endeavor to measure the capacity of the Bubble we had made use of by filling it with Water that we might the better know how much Water answer'd in weight to ¾ of a Grain of Air but notwithstanding all the diligence that was used to preserve so brittle a Vessel it broke before we could perfect that we were about and we were not then provided of another Bubble fit for our turn The haste I was in My Lord when I sent away the last Sheet made me forget to take notice to you of a Problem that occurr'd to my thoughts upon the occasion of the slow breaking of the Glass Bubble in our evacuated Receiver For it may seem strange since by our sixth Experiment it appears that the Air when permitted will by its own internal Spring expand it self twice as much as Mersennus was able to expand it by the heat even of a candent AEolipile Yet the Elater of the Air was scarce able to break a very thin Glass Bubble and utterly unable to break one somewhat thicker within whose cavity it was imprison'd whereas Air pen'd up and agitated by heat is able to perform so much more considerable effects that not to mention those of Rarefaction that are more obvious the Learned Jesuit Cabaeus he that writ of the Load-stone relates That he saw a Marble Pillar so vast that three men together with display'd arms could not imbrace it and that 1000 Yoke of Oxen drawing it several ways with all their strength could not have torn it assunder quite broken off in the midst by reason of some Wood which happening to be burnt just by the Pillar the heat proceeding from the neighbouring Fir so rarefied some Air or Spirituous Matter which was shut up in the cavities of the Marble that it broke through the solid Body of the Stone to obtain room to expand it self I remember I have taken notice that probably the reason why the included Air did not break the hermetically seal'd Bubbles that remain'd intire in our emptyed Receiver was That the Air being somewhat rarefied by the flame imploy'd to close the Glass its Spring upon the recess of the heat grew weaker than before But though we reject not that ghess yet it will not in the present case serve the turn because that much smaller Glass bubbles exactly clos'd will by the included Air though agitated by the heat of a very moderate Fire be made to fly in pieces Whether we may be assisted to salve this Problem by considering that the heat doth from within vehemently agitate the Corpuscles of the Air and add its assistance to the Spring they had before I shall not now examine since I here but propose a Problem and that chiefly that by this memorable Story of Cabaeus notice may be taken of the prodigious power of Rarefaction which hereby appears capable of performing stranger things than any of our Experiments have hitherto ascrib'd to it We should hence My Lord immediately proceed to the next Experiment but that we think it fit on this occasion to acquaint You with what some former tryals though not made in our Engine have taught us concerning what we would have discover'd by the newly mention'd Bubble that broke And this the rather because a great part of this Letter supposing the gravity of the Air it will not be impertinent to determine more particularly than hitherto we have done what gravity we ascribe to it We took then an AEolipile made of Copper weighing six ounces five drachms and eight and forty grains this being made as hot as we durst make it for fear of melting the mettle or at least the Sodar was removed from the fire and immediately stopped with hard Wax that no Air at all might get in at the little hole wont to be left in AEolipiles for the fumes to issue out at Then the AEolipile being suffer'd leasurely to cool was again weighed together with the Wax that stopt it and was found to weigh by reason of the additional weight of the Wax six ounces six drachms and 39 grains Lastly the Wax being perforated without taking any of it out of the Scale the external Air was suffered to rush in which it did with some noise and then the AEolipile and Wax being again weighed amounted to six ounces six drachms and 50 grains So that the AEolipile freed as far as our fire could free it from its Air weighed less than it self when replenished with Air full eleven grains That is the Air containable within the cavity of the AEolipile amounted to eleven grains and somewhat more I say somewhat more because of the particles of Air that were not driven by the fire out of the AEolipile And by the Way if there be no mistake in the observations of the diligent Mersennus it may seem strange that it should so much differ from 2 or 3 of ours in none of which we could rarefie the Air in our AEolipile though made red hot almost all over and so immediately plung'd into cold Water to half that degree which he mentions namely to
Statical and Mechanical Experiments rise to the height of Five and twenty German Leagues if not of some hundred of common Miles And this conjecture it self may appear very injurious to the height whereunto Exhalations may ascend if we will allow that there was no mistake in that strange Observation made at Tolouse in a clear Night in August by the diligent Mathematician Emamuel Magnan and thus Recorded by Ricciolus for I have not at hand the Author 's own Book Vidit says he ab hora undecima post meridiem usque ad mediam noctem Lunâ infra horizontem positâ nubeculam quandam lucidam prope Meridianum fere usque ad Zenith diffusam quae consideratis omnibus non poterat nisi à sole illuminari ideoque altior esse debuit tota umbra terrae Addit continues Ricciolus simile quid evenisse Michaeli Angelo Riccio apud Sabinos versanti nempe viro in Mathesi eruditissimo Various Observations made at the feet tops and interjacent parts of high Mountains might perchance somewhat assist us to make an estimate in what proportion if in any certain one the higher Air is thicker than the lower and ghess at the difform consistence as to laxity and compactness of the Air at several distances from us And if the difficulties about the refractions of the Celestial Lights were satisfactorily determin'd that might also much conduce to the placing due limits to the Atmosphere whose Dimensions those Observations about Refractions seem hitherto much to contract But for the present we dare not pronounce any thing peremptorily concerning the height of it but leave it to farther inquiry contenting our selves to have manifested the mistake of divers eminent Modern Writers who will not allow the Atmosphere to exceed above two or three Miles in height as the Famous Kepler will not the Aër refractivus and to have rendred a reason why in the mention we made in the Notes upon the first Experiment touching the height of the Atmosphere we scrupled not to speak of it as if it might be many Miles high EXPERIMENT XXXVII WE will now proceed to recite a Phaenomenon which though made amongst the first we thought fit not to mention till after many others that we might have the opportunity to observe as many Circumstances of it as we could and so present Your Lordship at once most of what we at several times have taken notice of concerning so odd a Phaenomenon Our Engine had not been long finish'd when at the first leisure we could steal from our occasions to make trial of it we caused the Air to be pump'd out of the Receiver and whilst I was busied in entertaining a Learned Friend that just then came to visit me an Ingenious By-stander thought he perceiv'd some new kind of Light in the Receiver of which giving me hastily notice my Friend and I presently observ'd that when the Sucker was drawn down immediately upon the turning of the Key there appear'd a kind of Light in the Receiver almost like a faint flash of Lightning in the Day-time and almost as suddenly did it appear and vanish Having not without some amazement observ'd divers of these apparitions of Light we took notice that the Day was clear the hour about ten in the Morning that the only Window in the Room faced the North and also that by interposing a Cloak or any opacous Body between the Receiver and the Window though the rest of the Room were sufficiently enlightned yet the flashes did not appear as before unless the opacous Body were removed But not being able on all these Circumstances to ground any firm Conjecture at the cause of this surprising Phaenomenon as soon as Night was come we made the Room very dark and plying the Pump as in the Morning we could not though we often try'd find upon the turning of the Key so much as the least glimmering of Light whence we inferred that the flash appearing in the Receiver did not proceed from any new Light generated there but from some reflexions of the light of the Sun or other Luminous Bodies plac'd without it though whence the Reflexion should proceed it pos'd us to conjecture Wherefore the next Morning hoping to inform our selves better we went about to repeat the Experiment but though we could as well as formerly exhaust the Receiver though the place wherein we made the trial was the very same and though other Circumstances were resembling yet we could not discover the least appearance of Light all that Day nor on divers others on which trial was again fruitlesly made nor can we to this very time be sure a Day before-hand that these Flashes will be to be seen in our great Receiver Nay having once found the Engine in a good humour if I may so speak to shew this trick and sent notice of it to our Learned Friend Dr. Wallis who express'd a great desire to see this Phaenomenon though he were not then above a Bow-shoot off and made haste to fatisfie his Curiosity yet by that time he was come the thing he came for was no longer to be seen so that having vainly endeavoured to exhibit again the Phaenomenon in his prefence I began to apprehend what he might think of me when unexpectedly the Engine presented us a flash and after that a second and as many more as suffic'd to satisfie him that we might very well confidently relate that we have our selves seen this Phaenomenon though not confidently promise to shew it others And this unsuccessfulness whereto our Experiment is liable being such that by all our watchfulness and trials we could never reduce it to any certain Rules or Observations since in all constitutions of the Weather times of the Day c. It will sometimes answer and sometimes disappoint our expectations We are much discourag'd from venturing to frame an Hypothesis to give an account of it which if the Experiment did constantly succeed might the more hopefully be attempted by the help of the following Phaenomena laid together some of them produc'd upon trials purposely made to examine the validity of the conjectures other trials had suggested First then we observ'd that the Apparition of Light may be made as well by Candle-light as by Day-light and in whatever position the Candle be held in reference to the Receiver as on this or that hand of it above it beneath it or any other way provided the beams of Light be not hinder'd from falling upon the Vessel Next we noted that the flash appears immediately upon the turning of the Key to let the Air out of the Receiver into the emptied Cylinder in so much that I remember not that when at any time in our great Receiver the Stop-cock was open'd before the Cylinder was exhausted whereby it came to pass that the Air did rather descend than rush into the Cylinder the often mentioned flash appear'd to our eyes Yet we farther observ'd that when instead of the great Receiver we made use of a
So that being unable to give an account of these odd changes in our Tincture which we suppose we have not yet lost though we know not whether it hath lost its fickle Nature either by those of the Air or any thing else that occurr'd to our thoughts we could not but suspect that there may be in divers Bodies as it were Spontaneous Mutations that is such changes as depend not upon manifest Causes But My Lord what hath been all this while said concerning our Phaenomenon is offer'd to You not as containing a satisfactory account of it but to assist You to give Your self one EXPERIMENT XXXVIII WE took a Glass Vessel open at the top and into it we put a mixture of Snow and common Salt such a mixture as we have in another Treatise largely discoursed of and into the midst of this mixture we set a Glass of a Cylindrical form closely stopp'd at the lower end with Plaister and open at the upper at which we fill'd it with common Water These things being let down into the Receiver and the Pump being set on work the Snow began to melt somewhat faster than we expected Whether upon the account of the exsuction of the Air or because there was but little of the Snow or whether for any other Reason it appear'd doubtfull But however by that time the Receiver had been considerably exhausted which was done in less than ¼ of an hour we perceived the Water near the bottom of the Glass Cylinder to Freeze and the Ice by a little longer stay seem'd to encrease and to rise somewhat higher than the surface of the surrounding Liquor whereinto almost all the Snow and Salt were resolv'd The Glass being taken out it appear'd that the Ice was as thick as the inside of the Glass it fill'd though into that I could put my Thumb The upper surface of the Ice was very concave which whether it were due to any unheeded accident or to the exsuction of the Air we leave to be determin'd by farther trial And lastly the Ice held against the Light appear'd not destitute of Bubbles though some By-standers thought they were fewer than would have been found if the Water had been frozen in the open Air. The like Experiment we try'd also another time in one of our small Receivers with not unlike success And on this occasion My Lord give me leave to propose a Problem which shall be this Whence proceeds that strange force that we may sometimes observe in frozen Water to break the Bodies that imprison it though hard and solid That there is such a force in Water expos'd to Congelation may be gathered not only from what may be often observ'd in Winter of the bursting of Glasses too close stopp'd fill'd with Water or aqueous Liquors but by Instances as much more considerable as less obvious For I remember that an Ingenious Stone-cutter not long since complain'd to me That sometimes through the negligence of Servants the Rain being suffered to soak into Marble Stones the supervening violent Frosts would burst the Stones to the Possessour's no small damage And I remember another Trades-man in whose House I had Lodgings was last Winter complaining that even Implements made of Bell-metal being carelesly expos'd to the wet have been broken and spoil'd by the Water which having gotten into the little Cavities and Crannies of the Metal was there afterwards frozen and expanded into Ice And to these Relations we can add one of the formerly mention'd Cabaeus's whereby they not only may be confirm'd but are surpass'd For he tells us That he saw a huge Vessel of exceeding hard Marble split asunder by congeal'd Water whose rarefaction saith our Author prov'd so vehement that the hardness of the Stone yielded to it and so a vessel was broken which would not have been so by 100 Yoke of Oxen drawing it several ways I know My Lord that to solve this Problem it will be said That Congelation doth not as is commonly but erroneously presum'd reduce Water into less room than it possess'd before but rather makes it take up more And I have elsewhere prov'd by particular Experiments That whether or no Ice may be truly said to be Water rarefi'd for that seems questionable it may be said to take up more room than the Water did before Glaciation But though we grant that freezing makes Water swell yet how cold which in Weather-Glasses manifestly condenseth the Air should expand either the Water or the intercepted Air so forcibly as to perform such things as we have newly related will yet remain a Problem EXPERIMENT XXXIX WE took an Oval Glass clear and lest it should break pretty strong with a short Neck at the obtuser end through this Neck we thrust almost to the bottom a Pipe of Glass which was closely cemented to the newly mention'd Neck the upper part of which Pipe was drawn in some places more slender than a Crows Quill that the changes of the Air in that Glass Egg might be the more conspicuous Then there was convey'd into the Glass five or six Spoon-fulls of Water part of which by blowing Air into the Egg was rais'd into the above-mention'd slender part of the Pipe so that the Water was interpos'd between the external Air and that included in the Egg. This Weather glass delineated in the fourteenth Figure was so plac'd and clos'd up in the cavity of one of our small Receivers that only the slender part of the Pipe to the height of four or five Inches passing thorow a hole in the Cover remain'd expos'd to the open Air. The Pump being set a work upon the exsuction of the Air the Water in the Pipe descended about a quarter of an Inch and this upon two or three reiterated trials which seem'd sufficiently to argue that there was no heat produc'd in the Receiver upon the exsuction of the Air For even a little heat would probably have been discover'd by that Weather-glass since upon the bare application of my hand to the outside of the Receiver the warmth having after some time been communicated or propagated through both the Glasses and the interval betwixt them to the imprison'd Air did so rarefie that as to inable it by pressing upon the subjacent Water to impel that in the Pipe very many times as far as it had fallen downwards upon the exsuction of the Air. Yet shall not we conclude that in the cavity of the Receiver the cold was greater after the exsuction of the Air than before For if it be demanded what then could cause the fore-mention'd subsiding of the Water it may be answered That probably it was the reaching of the Glass Egg which upon the exsuction of the ambient Air was unable to resist altogether as much as formerly the pressure of the included Air and of the Atmosphere which by the intervention of the Water press'd upon its concave surface Which seem'd probable as well by what was above deliver'd in the Experiment about
intelligible will be more properly considered in the second part of our Discourse to which we will therefore now proceed The II. Part. Wherein the Adversaries Funicular Hypothesis is examin'd CHAP. I. What is alledged to prove the Funiculus is consider'd and some Difficulties are propos'd against the Hypothesis THE Hypothesis that the Examiner would as a better substitute in the place of ours is if I mistake it not briefly this That the things we ascribe to the weight or spring of the Air are really perform'd by neither but by a certain Funiculus or extremely thin substance provided in such cases by Nature ne detur vacuum which being exceedingly rarefied by a forcible distension does perpetually and strongly endeavour to contract it self into dimensions more agreeable to the nature of the distended body and consequently does violently attract all the bodies whereunto it is contiguous if they be not too heavy to be remov'd by it But this Hypothesis of our Authors does to me I confess appear liable to such Exceptions that though I dislik'd that of his Adversaries yet I should not imbrace his but rather wait till time and further Speculations or tryals should suggest some other Theory fitter to be acquiesc'd in than this which seems to be partly precarious partly unintelligible and partly insufficient and besides needless though it will not be so convenient to prove each of these apart because divers of my Objections tend to prove the Doctrine against which they are alledged obnoxious to more than one of the imputed Imperfections First then the Arguments by which our Author endeavours to evince his Funiculus are incompetent for that end The Arguments which he proposes in his sixth Chapter where he undertakes to make good his Assertion I there find to be three The first he sets down in these words Constat hoc primò exjam dict is Capite praecedente nequit enim argentum descendens sic digitum deorsum trahere tuboque affigere nisi à tali Funiculo suspendatur eumque suo pondere vehementer extendat ut per se patet But to this proof answer has been made already in the former Part of this Discourse onely whereas the Author seems to refer us to the foregoing Chapter we will look back to it and take notice of what I find there against the Vacuists For though I neither am bound nor intend in this Discourse to declare my self for or against a Vacuum yet since I am now writing against the Funicular Hypothesis it will much conduce to shew that it is not firmly grounded if I examine what he here alledges against the Assertors of a Vacuum In the next place therefore I consider that according to the Examiner there can be no Vacuum and that he makes to be the main reason why Nature in the Torricellian and our Experiments does act after so extraordinary a manner as is requisite to the production of his Funiculus For in the 47 th Page having in his Adversaries name demanded what need there is at the descent of the Quicksilver that before it falls a superficies should be separated from it and extended Respondeo sayes he ideo hoc fieri ne detur vacuum cum nihil aliud ibi adsit quod loco argenti descendentis possit succedere To which he immediately subjoyns with what cogency I will not now examine Atque hinc plane confirmatur commune illud per tot jam elapsa secula usurpatum in Scholis axioma viz. Naturam à vacuo abhorrere And though he seem to make his Funiculus the immediate cause of the Phaenomena occurring in the Torricellian and our Experiments yet that if you pursue the inquiry a little higher he resolves them into Natures abhorrency of a Vacuum himself plainly informs us in the next page Nam licet sayes he immediata ratio cur aqua v. g. ex hydria hortulana superne clausa quo exemplo utuntur non descendat non sit metus va ui sed ea quam modo diximus nempe quod non detur sufficiens pondus ad solvendum illum nexum quo adhaereat aqua clausae hydriae summitati ad eam tamen rationem tandem necessario veniendum est But though as well our Author 's Funiculus as the other scarce conceivable Hypotheses that learned men have devised to account for the suspension of the Quicksilver otherwise than by the resistance of the external Air seem to have been excogitated onely to shun the necessity of admitting a Vacuum yet I see not how our Examiner cogently proves either that there can be none in rerum naturâ or that De facto there is none produc'd in these Experiments For in his fifth Chapter where he professedly undertakes that task he has but these two incompetent Arguments The first is drawn from the attraction as he supposes of the Finger into the deserted cavity of the Tube in the Torricellian Experiment Quae quidem sayes he tam vehemens tractio adhaesio cum non nisi à reali aliquo corpore inter digitum argentum constitutum queat provenire manifestum est spatium illud vacuum non esse sed verâ aliquâ substantiâ repletum But to this Argument having already given an Answer let us without staying to urge that the Vacuists will perhaps object that they see not a Necessity though they should admit of Traction in the case that the internal substance must therefore perfectly replenish the deserted Cavity without pressing this I say let us consider his other which he draws from the Diaphaneity of the deserted part of the Tube which space he sayes were it empty would appear like a little black Pillar Eo quod nullae species visuales neque ab eo neque per illud possunt ad oculum pervenire But not to engage our selves in Optical Speculations and Controversies if we grant him somewhat more than perhaps he can prove yet as the Experiment will not demonstrate that there is nothing of body in any part of the space deserted by the Mercury so neither will the Argument conclude as the Proposer of it does twice in this Chapter That space ver â aliquâ substantiâ repleri For according to the Hypothesis of the Epicureans and other Atomists who make Light to be a corporeal Effluvium from lucid bodies and to consist of Atoms so minute as freely to get in at the narrow Pores of Glass there will be no cause to deny interspers'd Vacuities in the upper part of the Tube For the Corpuscles of Light that permeate that space may be so numerous as to leave no sensible part of it un-inlightned and yet may have so many little empty Intervals betwixt them that if all that is corporeal in the space we speak of were united into one lump it would not perhaps adequately fill the one half not to say the tenth or even the hundredth part of the whole space According to what we have noted in the 17. Experiment that a
the onely Example whereby he endeavours to illustrate the generation of his Funiculus yet I presume he scarce expects we should think it an apposite one For besides that there here intervenes a conspicuous and powerful Agent namely an actual Fire to sever and agitate the parts of the Candle and besides that there is a manifest wasting of the Wax or Tallow turn'd into flame besides these things I say we must not admit that the Fuel when turn'd into a flame does really fill I say not with our Author more than a thousand times but so much as twice more of genuine space than the Wax 't was made of For it may be said that the flame is little or nothing else than an aggregate of those Corpuscles which before lay upon the upper superficies of the Candle and by the violent heat were divided into minuter particles vehemently agitated and brought from lying as it were upon a flat to beat off one another and make up about the Wiek such a figure as is usual in the flame of Candles burning in the free Air. Nor will it necessarily follow that the space which the flame seems to take up should contain neither Air nor AEther nor any thing else save the parts of that flame because the eye cannot discern any other body there For even the smoke ascending from the snuff of a newly-extinguish'd Candle appears a dark pillar which to the eye at some distance seems to consist of smoke when as yet there are so many Aerial and other invisible Corpuscles mingled with it as if all those parts of smoke that make a great show in the Air were collected and contiguous they would not perhaps amount to the bigness of a Pins head as may appear by the great quantity of streams that in Chymical Vessels are wont to go to the making up of one drop of Spirit And therefore it does not ill fall out for our turn that the Examiner to inforce his former Example alledges the turning of a particle of Quicksilver into vapour by putting fire under it for if such be the Rarefaction of Mercury 't is not at all like to make such a Funiculus as he talks of since those Mercurial Fumes appear by divers Experiments to be Mercury divided and thrown abroad into minute parts whereby though the body obtain more of Surface than it had before yet it really fills no more of true and genuine space since if all the particular little spaces fill'd by these scatter'd Corpuscles were reduc'd into one as the Corpuscles themselves often are in Chymical Operations they would amount but to one total space equal to that of the whole Mercury before rarefaction But these Objections against this Explication are not all that I have to say against our Adversaries Funiculus it self For I farther demand how the Funiculus comes by such hooks or graple-irons or parts of the like shape to take fast hold of all contiguous bodies and even the smoothest such as Glass and the calm surface of Quicksilver Water Oyle and other fluids And how these slender and invisible hooks cannot onely in the tersest bodies find an innumerable company of ears or loops to take hold on but hold so strongly that they are able not alone to lift up a tall Cylinder of that very ponderous metal of Quick-silver but to draw inwards the sides of strong Glasses so forcibly as to break them all to pieces And 't is also somewhat strange that Water and other fluid bodies whose parts are wont to be so easily separable should when the Funiculus once layes hold on the superficial Corpuscles presently emulate the nature of consistent bodies and be drawn up like Masses each of them of an intire piece though even in the exhausted Receiver they appear by their undulation when they are stir'd by Bubbles that pass freely through them and many other signs to continue fluid bodies It seems also very difficult to conceive how this extenuated substance should require so strong a spring inward as the Examiner all along his books ascribes to it Nor will it serve his turn to require of us in exchange an Explication of the Airs spring outward since he acknowledges as well as we that it has such a spring I know that by calling this extenuated substance a Funiculus he seems plainly to intimate that it has its spring inward upon the same account that Lute-strings and Ropes forcibly stretch'd have theirs But there is no small disparity betwixt them for whereas in strings there is requir'd either wreathing or some peculiar and artificial texture of the component parts a rarefaction of Air were it granted does not include or infer any such contrivance of parts as is requisite to make bodies Elastical And if the Cartesian Notion of the cause of Springiness be admitted then our extenuated substance having no Pores to be pervaded by the materia subtilis to which besides our Author also makes Glass impervious will be destitute of Springiness And however since Lute-strings Ropes c. must when they shrink inwards either fill up or lessen their Pores and increase in thickness as they diminish in length our Examiners Funiculus must differ very much from them since it has no Pores to receive the shrinking parts and contracts it self as to length without increasing its thickness Nor can it well be pretended that this self contraction is done ob fugam vacui since though it should not be made a Vacuum would not ensue And if it be said that it is made that the preternaturally stretch'd Body might restore it self to its natural dimensions I answer That I am not very forward to allow acting for ends to Bodies inanimate and consequently devoid of knowledge and therefore should gladly see some unquestionable Examples produc'd of Operations of that nature And however to me who in Physical enquiries of this nature look for efficient rather than final causes 't is not easie to conceive how Air by being expanded in which case its force like that of other rarefi'd Bodies seems principally to tend outwards as we see in fired Gun-powder in AEolipiles in warm'd Weather-glasses c. should acquire so prodigious a force of moving contiguous Bodies inwards Nor does it to me seem very probable that when for instance part of a polish'd Marble is extended into a Funiculus that Funiculus does so strongly aspire to turn into Marble again I might likewise wish our Author had more clearly explicated how it comes to pass which he all along takes for granted that the access of the outward Air does so much and so suddenly relax the tension of his Funiculus since that being according to him a real and Poreless body 't is not so obvious how the presence of another can so easily and to so strange a degree make it shrink But I will rather observe that 't is very unlikely that the space which our Adversary would have replenish'd with his Funicular substance should be full of little
compress a Glass on all sides especially one of that thickness there mention'd as to break it p. 72. Verius c. It is therefore more truly answered that the Glass is therefore so broken because by that exsuction its sides are more vehemently drawn inwards than by reason of the figure unfit for resistency they were able to resist For seeing the included Air doth most firmly stick to the sides of the Glass to draw out the Air will be nothing elst but to endeavour to bend the fides of the Glass inwards Ibid. Sed profecto c. But truly this seems too far remov'd from Truth and may be by this alone sufficiently refuted Because if the pressure of the Air which descends by that Tube into the Vial be so great as to break the Vial it self it ought certainly before the breaking of the Vial very much to move the water in which the Tube is immers'd and to excite bubbles in it c. as appears if any one blowing through that Tube doth make but an ordinary pressure upon the water But it is sure that the water before the Vial is broken doth not move at all as the Experimenter will find p. 73. Licet c. Though the Tube had been shut at the top the Vial had doubtless been broken after the same manner p. 74. Sed rectius c. But it is more rightly thence inferr'd that that Cylinder did nothing there before p. 75. Dice c. I say then that the Quicksilver doth by that exhaustion so descend in the Tube because it is drawn downwards by the Air incumbent upon the restagnant Quicksilver For that incumbent Air being by its exhaustion greatly rarefied and extended vehemently contracts its self and by this contraction doth endeavour to lift the restagnant Mercury out of its Vessel whence it comes to pass that the restagnant Mercury now less gravitating upon the bottom of its Vessel the Quicksilver in the Tube must descend as is manifest in it self So that it is no wonder that the external Air afterwards entring the Quicksilver again ascends seeing by that ingress the force which elevates the restagnant Quicksilver is weakned Ibid. Atque hinc c. And hence is a reason also given of another thing which is there noted namely that by the violent intrusion of the external Air into the Receiver the Quicksilver ascended considerably above 29 Inches and an half For as by the extraction of the Air the Quicksilver is deprest below its station so by the intrusion of new Air it is elevated above it p. 77. Nam si c. For if it were kept up by that it ought rather to ascend than descend in colder weather because the Air then would be more dense and heavy Therefore the Quicksilver is not upheld by the AEquilibrium of Air as is asserted p. 78. Hinc fit c. Hence it comes to pass that this Funicle being contracted by the cold the water doth ascend in cold weather but doth descend in hot because by heat the Funicle is dilated Ibid. Ego certè c. I truly do not doubt but there are some such occult causes by which the slender Funicle that suspends as we mentioned in the 10. Chapter the Quicksilver in the Tube is sometimes lengthned sometimes shortned and so doth sometimes let down and sometimes lift up the Quicksilver p. 79. In decimo nono c. In the 19. he shews that water doth in the same manner descend upon the exhausting the Receiver as he had shewn Quicksilver in the foregoing Chapter to descend Of both which seeing there is the same cause there is no reason we should any longer insist on this p. 80. Nam fi c. For if it were done so these bubbles ought not so to have ascended from the bottom of the Vessel as it is asserted they did both in this and the following Experiments that treat of bubbles but from the upper part of the water where they are less comprest as it is apparently manifest p. 81. Respondeo c. I answer that the water upon that exhaustion of the Air doth not so ascend of its own accord but is violently drawn or lifted upwards by that rarefied Air contracting it self For as water doth suffer some compression as appears by experience so here also it suffers some distension And hence it is clearly manifest why these bubbles should arise rather from the bottom of the Vessel than from the upper part of the water For when that vehement suction doth endeavour to elevate the water from the bottom of the Vial there arises there a certain subtile matter which being turned into bubbles doth so ascend as is mentioned in the 15. Chapter and the 4. Experiment p. 82. Certum esse c. It is certain that that Opinion is sufficiently refuted by this single Experiment p. 83. Necesse c. It must needs be that that stone could not otherwise descend than by leaving behind it such a thin substance as is left by Quicksilver or Water descending in like manner Ibid. Vnde c. Whence I plainly conceive that if two perfectlypolish'd Marbles were so joyned that no Air at all were left between them they could not be drawn asunder by all the power of Man Ibid. Vti etiam c. Which also is confirmed by the Example the Author there brings of a Brass Plate sticking so close to a Marble Table that by a lusty Youth who boasted of his own strength it could not be lifted off by a Ring fixed to its Centre p. 84. Eodem c. Almost the same manner as we see in Cupping-glasses applied to a Patients back in which the flame being extinct the rarefied Air contracting it self doth so vehemently as we see lift up and draw the flesh within the Glass p. 85. In his c. In these three there is nothing occurs to be peculiarly here explicated the account of which is not easie from what is already delivered Ibid. Existimo c. But I think that Whiteness should be rather called a reflex than an innate light because as the Author bears witness it appears not in the dark but only in the day or by Candle-light p. 86. Verum c. But it seems impossible that such Animals should dye so soon only for want of a thicker Air. p. 87. Quia per c. Because by the self-contraction of the rarefied Air their breath is drawn out of their bodies Ibid. Atque hinc c. And thence also arose those vehement Convulsions which the Author there mentions certain small Birds to have endured before their death p. 89. In mala c. In a bad Cause they can do no other but who compell'd them to undertake a bad Cause A Summary of the Contents of the several Chapters PART I. WHerein the Adversaries Objections against the Elaterists are examined CHAP. I. The occasion of this Writing pag. 1. Franciscus Linus his civility in writing obliges the Author to the like
p. 2. Books concerning the Torricellian Experiment wherewith the Author was formerly unacquainted ibid. The Inconvenience of Linus's Principles ibid. The division of the ensuing Treatise into three parts CHAP. II. A repetition of the Adversary's Opinion and Arguments His Arguments against the Weight of the Air examined p. 4. An Experiment of his to prove that the external Air cannot keep up twenty Inches of Quick-silver from descending in a Tube twenty Inches long ibid. The Author's answer and reconciliation of the Experiment to his Hypothesis p. 5. and the relation of an Experiment of the Author's wherein only water being employed instead of Quick silver without other alteration of the Adversaries Experiment it agrees well with and confirms the Author's Hypothesis and his Explication of the mentioned Experiments ibid. That Water hath no Spring at all or a very weak one p. 6. The second Argument examined ib. Whether the same quantity of Air can adequately fill a greater space p. 7. The conceivableness of both Hypotheses compared ibid. CHAP. III. Another Argument of the Adversaries from an Experiment wherein the Mercury sinking draws the Finger into the Tube examined Q. Whether the Mercury placed in its own station is upheld by the external Air or suspended there by an internal Cord p. 7 8. CHAP. IV. A repetition of Franciscus Linus his principal Experiment wherein in a Tube of twenty Inches long the Finger on the top is supposed to be strongly drawn and suck'd into the Tube p. 8. The Experiment explicated without the assistance of Suction by the pressure of the external Air upon the outside of the Finger thrust not suck'd in p. 9. Franciscus Linus his argumentation considered p. 10. CHAP. V. The Eximiners last Experiment considered in which he argues against the Author's Hypothesis because Mercury is not suck'd out of a Vessel through a Tube so easily as Water is p. 11 12. An Experiment of Monsieur Paschall shewing that if the upper part of a Tube could be freed from the pressure of all internal Air the Mercury would by the pressure of the outward Air be carried up into the Tube as well as Water till it had attained a height great enough to make its weight equal to that of the Atmosphere p. 13. Why in a more forcible respiration the Mercurial Cylinder is raised higher than in a more languid p. 14. A Remark by the bie That the contraction of the Adversaries supposed Funiculus is not felt upon the Lungs p. 15. CHAP. VI. The examination of the Adversaries 4th Chapter p. 15. That the Spring of the Air may have some advantage in point of force above the Weight of it p. 16. That it is unintelligible how the same Air can adequately fill more space at one time than at another p. 17. PART II. Wherein the Adversaries Funicular Hypothesis is examined CHAP. I. Wherein what is alledged to prove the Funiculus is considered and some Difficulties are proposed against the Hypothesis The nature of this supposed Funiculus described p. 18. That according to the Adversaries Opinion this Funiculus is produced by Nature only to binder a Vacuum p. 19 20. The Adversaries proofs that there is no Vacuum examined p. 20 21. That where no sensible part is un-enlightned the place may not be full of light p. 21. The same true in Odours ibid. That there may be matter enough to transmit the impulse of Light though betwixt the Particles of that matter there should be store of Vacuities intercepted p. 22. That a solid Body bath no considerable sense of pressure from fluid bodies p. 24. Of the causes of the Vibrations of Quick-silver in its descent p. 24 25. CHAP. II. Wherein divers other Difficulties are objected against the Funicular Hypothesis As that in Liquors of divers weights and natures as Water Wine and Quick-silver there should be just the same weight or strength to extend them into a Funiculus p. 27. That whereas the Weight and Spring of the Air is inferr'd from unquestioned Experiments the account of that Hypothesis is strange and unsatisfactory As that the Quick-silver doth not only touch the top of the Glass but stick to it That Nature wreaths a little rarefied Air into a strong rope even able to draw up Quick-silver p. 27 28. That Rarefaction is performed by a certain unknown force or vis divulsiva ibid. That thin Surfaces are left successively one after another that these Surfaces are contrived into strings that may be stretch'd without being made more slender c. p. 29. The illustration of the manner how his Funiculus is made from the rarefaction of Wax or Tallow in a lighted Candle is considered p. 30. and shewed not to be apposite ibid. Divers other difficulties and improbabilities manifested in the Funicular Hypothesis p. 31. Of the inward Spring necessary to the contraction of his Funiculus p. 31 32. An Argument from a Pendulum's moving freely in an exhausted Receiver that the medium it moves in doth not consist of innumerable exceedingly-stretch'd strings p. 35. CHAP. III. The Aristotelean Rarefaction proposed by the Adversary examined What Rarefaction and Condensation is p. 34. Three ways of explicating how Rarefaction is made p. 34 35. Absurdities in resolving the Magdeburg Experiment by the Aristotelean way of Rarefaction p. 36. The inconveniences of the several Hypotheses compared p. 37. The difficulties in the Adversaries explaining Rarefaction by Bodies infinitely divisible ibid. The difficulties of explaining it by supposing Bodies made up of parts indivisible p. 39 40. The difficulties wherewith his Condensation is incumbred as that it infers Penetration of Dimensions c. p. 41. CHAP. IV. A Consideration pertinent to the present Controversie of what happens in trying the Torricellian and other Experiments at the top and feet of Hills That the Funicular Hypothesis is but an Inversion of the Elastical one supposing a Spring inwards the other outwards one performing its effects by Pulsion the other by Traction p. 46. That these trials on the tops and feet of Hills determine the case for the Author's Hypothesis p. 47. The truth of the Observation of Monsieur Paschall confirmed p. 48. and the several trials that have been made of it related ibid. A trial of the Author 's from the Leads of the Abbey-Church at Westminster p. 50 51 52. That the subsidence of the Mercury at the top of a Hill proceeds from the lightness of the Atmospherical Cylinder there p. 53. The relation of an Experiment lately made at Hallifax Hill in confirmation of the former p. 54. CHAP. V. Two new Experiments touching the measure of the force of the Spring of the Air compress'd and dilated That it is capable of doing far more than the necessity of the Author's Hypothesis requires p. 55. The first Experiment of compressing Air by pouring Mercury into a crooked Tube related ibid. Wherein the same Air being brought to a degree of density twice as great obtains a Spring twice as strong as before p. 57. A Table of
the Society those Opinions which how Erroneous soever he is pleas'd to think them I must own to be mine And this Justice I the rather do It because 't is all that I am to do in this Treatise on their Behalf not onely for the Reasons above intimated but because the Vindication of such an Assembly against Mr. Hobbs deserves a better Pen than mine though it doth not need it Secondly undertaking then the Defence of my own Cause without Interessing them in my Quarrel I must next admonish the Reader that whereas Mr. Hobbs writes as if the new Experiments were devised or at least employ'd to prove a Vacuum he is in this likewise mistaken For neither has the Society declared either for or against a Vacuum nor have I Nay I have not only forborn to profess my self a Vacuist or a Plenist but I have in a fit place of my Epistle expressly said that I reserv'd the declaring of my own Opinion touching that Point to another Discourse which as yet is not published Wherefore Mr. Hobbs either injures or mistakes those whom he will needs make his Adversaries when he represents the new Experiments as Demonstrations alledg'd by profess'd Vacuists to disprove the Fulness of the World And though I shall be oblig'd in the following Discourse to reject Mr. Hobbs's Supposition of a Plenum yet I intend not thereby to declare whether or no I do absolutely allow a Vacuum But that which I drive at and which alone my present Work exacts is to shew that I may reasonably oppose the Hypothesis of a Plenum as it is stated by Mr. Hobbs and consequently unless he had better prov'd it I may very well refuse to let Him take it for demonstrated But I intend not to question whether or no other Plenists may not have better Arguments than his Principles have suggested to him nor to deny but that the Cartesians may without granting a Vacuum give a more plausible Account whether true or no of divers of the Phaenomena of our Engine if they will add as some of them of late have done the Spring of the Air to their Hypothesis That the Celestial Matter of which the Air does in great part consist is subtile enough freely to pass through the Pores of the closest Bodies and even Glass it self As for the Assertion Non dari vacuum though as I said I need not in this place declare my self either for or against it yet I confess I do not find that Mr. Hobbs though all along this Discourse he argues from this Principle against those he thinks Vacuists has demonstrated it For in his Book De Corpore though a main part of it depend upon the Plenitude of the World He has that I remember but one positive Argument indeed he thinks that unanswerable to evince it And that is drawn from this Experiment That if a Gardeners Watering-Pot be fill'd with Water the hole at the top being stopt the Water will not flow out at any of the holes in the bottom But if the finger be removed to let in the Air above it will run out at them all and as soon as the finger is applied to it again the Water will suddenly and totallay be stayed again srom running out The cause whereof subjoyns he seems to be no other but this that the Water cannot by its natural endeavour to descend drive down the Air below it because there is no place for it to go into unlesse either by thrusting away the next contiguous Air it proceed by continual endeavour to the hole at the top where it may enter and succeed in the place of the Water that floweth out or else by resisting the endeavour of the Water downwards penetrate the same and pass up through it But this Experiment as an obvious one and without dreaming that Mr. Hobbs had laid such stress upon it I have incidentally answer'd in what I say in two or three passages on the thirty third Experiment of my Epistle But after found that it had been more fully answer'd but upon Grounds some of which I do not need by my Learned Friend Dr. Ward with whom I thus take Mr. Hobbs his Argument to pieces The Cause according to Mr. Hobbs of the Suspension of the Water in the Vessel is that the Water cannot thrust away the Air. 2. And it cannot thrust that away unless Air succeed in its place 3. But Air cannot succeed in its place unless either by getting in at the upper Orifice or at the Holes that perforate the bottom By which view of the Argument it appears that the main force of it lies in the second Proposition but neither doth he demonstrate that which omission might excuse us from any further Answer nor indeed do I think it true For if the Watering Pot were tall enough what Reason is there why the Water should not run out at the Holes of it as Monsieur Paschall's Experiment mentioned in my Epistle manifests That though in a Glass-Tube Hermetically sealed at one end and several times as long as a Watering-Pot the Water will not fall down yet it will if the Tube exceed two or three and thirty foot or thereabouts And indeed the Suspension or Descent of the Water depends upon the Proportion betwixt the weight of the Aqueous Pillar that tends downwards and the Resistance or Pressure of the Air that can come to bear against it For as on the one side when the height of that Pillar is so increas'd as that it can outweigh the Atmospherical Cylinder that opposes its Descent 't will flow out till those two Cylinders come to an AEquilibrium so on the other side if instead of increasing the length of the Cylinder of the Water you lessen the pressure and resistance of the Air the Water will likewise descend though the Pillar be very short as I have shown in the nineteenth Experiment where by withdrawing some of the Air in the Receiver and thereby weakning its Spring the Water in a Tube Hermetically seal'd at one end of but about four foot long subsided about three foot though That the space relinquish'd by the Water was not full of Air as Mr. Hobbs his Argumentation requires it should be may be prov'd by what is there added That by letting in the outward Air when the Water was sunk so low it was immediately impell'd up again to the higher parts of the Tube And indeed as I elsewhere discourse it seems to me a difficult matter for those that reject as Mr. Hobbs justly does that Conceit of Natures Abhorring a Vacuum and making it as it were her business to hinder it to prove there can be no Vacuum at all by any particular Experiment For if the Fulness of the World be not made necessary either by the Nature of Body in general or by the Design of the Author of the Universe it can scarce be easie to prove by a particular Experiment that no Humane Force or Art can contrive a
both will think what I write the less rational for being civil or will let me suffer in their Opinions for neglecting to trouble them in aPhilosophical Controversie with matters that do but very little belong to it To skip then what Mr. Hobbs is pleased to say in the first Page of his Dialogue concerning some disputable discoveries about Sensation which he challenges to himself and to pass by divers other things in the second or third following pages which relate to him or to the Society he writes against rather than to the nature of the Air we should begin with the Opinion he thinks fit in the fifth page to impute to us as if we distinguish'd what is fluid from what is not so onely for so his Ratiocination imports by the bigness of the parts of which a Body consists But designing in an Appendix to be subjoyned to this Discourse to examine what I find in this Dialogue dispersed touching Fluidity I shall now onely say that he does very much mistake and mis-represent my Doctrine of Fluidity wherein I expresly teach That the principal cause or condition of it is not the size but the motion of the small parts that compose the fluid body To take up then the particulars we are to examine in the order as far as conveniently may be wherein I find them lye in the Authors Dialogue and passing by at present those things which either we have considered already or are not to consider in this place The first particular that offers it self to be taken notice of is this passage at the bottom of the twelfth page B. In vas apertum infudimus aquam in aqua fistulam statuimus erectam longam exilissimam observavimus autem aquam è vase subjecto in erectam fistulam ascendisse A. Nec mirum nam superficiem aquae particulae aëri interspersae aquaeque contiguae motu suo verberabant ita ut aqua non potuit in fistulam non ascendere sensibiliter quidem in fistulam valde angustam To this I say that 't is manifest by what I write in my Epistle that I did not then take upon me nor do I undertake in this place to assign the true reason of the propos'd Phaenomenon An Attempt of this kind has been since address'd to me which being ingenious if not also true may be consulted In the mean time I cannot but declare that I am no way satisfied with Mr. Hobbs's Exposition For to say nothing of the motion he ascribes to the particles dispersed through the Air he leaves the difficulty unsolved since there being common Air as well within the Cavity of the slender Pipes as without it he neither shews nor so much as offers at a reason why the pressure of the Air within should not resist the pressure of the same kind of Air without as we see it does in greater Pipes And possibly he would have past by this particular if he had not overlook'd the Advertisement I gave towards the close of the 35. Experiment That it would concern those who should undertake to shew the causes of this Phaenomenon to bethink themselves also of a reason why if the Experiment be tryed with Quicksilver instead of Water the Surface of the Liquor will instead of being higher be lower within the Pipe than without it Whereas if Mr. Hobbs's Explication be sufficient why should not the contrary happen in Quicksilver as well as in Water The next passage I have to consider is in the 13. page thus set down Siquis post impulsionem revulsionemque Suctoris aliquoties repetitam Epistomium superni orificii Recipientis conetur extrahere inveniet illud valde gravitare tanquam si multarum librarum pondus ab eo penderet Vnde contingit hoc A. Ab aëris qui est in Recipiente fortissimo conatu circulari facto à violento ingressu aëris inter superficiem Suctoris convexam Cylindri concavam generato per iteratam illam impulsionem revulsionemque Suctoris quam vos perperam vocatis exuctionem aëris Nam propter naturae plenitudinem Epistomium extrahi non potest quin aër qui est in Recipiente Epistomio contiguus una extrahendus sit Qui quidem aer si quiesceret facillimè Epistomium sequeretur sed dum velocissimè circuit satis difficulter sequitur id est videtur esse valde gravis B. Verisimile est Nam ut aër novus in Recipiens paulatim admittitur etiam apparentem illam gravitatem paulatim perdit But I do not much fear that this Explication will keep the Experiment from continuing to be thought by ingenious men a notable Confirmation of our Hypothesis For to pass by something that though I am no way satisfied with cannot well be examined in few words I answer First that if there be such a vehement circular endeavour as he imagines of the Air in the Receiver by which motion he elsewhere teaches as we have seen above that the Air rushes out with violence enough to make the Atmosphere lift up in our Cylinder above an hundred pound weight I see not why it should not rather throw out the stopple under consideration than hinder its extraction And I see not why when the external Air is re-admitted at the stop-cock into the exhausted Receiver and thereupon there does sensibly follow for a little while a whirling about of the included Air the stopple that just before seemed so much to resist the being drawn out should cease to make any such resistance Nor do I see how the plenitude of Nature should as is here intimated hinder the extraction of the stopple For according to the Plenists the World and the Receiver must be at all times equally full And if the contiguous Air must for Mr Hobbs's reason necessarily be extracted with the stopple in one case I see not why the like should not happen in another But since Mr. Hobbs is pleased to call us Experimentarian Philosophers let us shew that such Explications as these of his need not make us asham'd of the name I say then that it appears by our Experiments that there is no such Fortissimus conatus circularis in the exhausted Receiver as he pretends but that there is indeed an endeavour of the Ambient Atmosphere to press inwards the parts of the Glass and Cover that are contiguous to it For as I have also noted already a light Bladder suspended in the cavity of the Receiver betrayed no such motion as Mr. Hobbs here supposes To which I shall now adde that neither were a pair of Scales suspended within the same Cavity nor was a long Magnetical Needle that rested upon the point of another Needle at all whirled about by this imaginary motion of the Air. Besides if you leisurely loosen the Brass stopple so that it may be very near but not contiguous to the sides of the Socket you shall manifestly perceive a strong current of Air to flow into the Receiver at that passage And more
divided blended and opprest with the others have not the power to shine or burn till being by some spark or other body actually burning or by some other equivalent cause extricated they flock together in swarms and then are able to burn and shine that is to appear fire Which fire is yet but a part of the fewel as appears by the Phlegme Ashes and perhaps other incombustible parts of the Coal or other fewel So that the Atomists and divers others will not allow what Mr. Hobbs infers about an incendium And whereas he tells us he believes that no body thinks Particulas igneas à Sole eject as transire posse per substantiam globuli crystallini he seems to me to have very little heeded the Epicurean Hypothesis For not onely the learned Gassendus but I know not how many other Atomists besides other Naturalists Ancient and Modern expresly teach the Sun-beams to consist of fiery Corpuscles trajected through the Air and capable of passing through Glass whereby these Authors give an account of those specula ustoria that burn by reflexion These things I represent not that I intend here to adopt the Atomists Opinion of the nature of Fire of which I am not obliged to declare my thoughts here and have done it elsewhere but to shew that Mr. Hobbs's Arguments are not a sufficient ground for so heavy a Censure And if a Coal be kindled at one end though Mr. Hobbs would have the kindled end a Coal not Fire yet if he please to hold it in his naked hand he may find that differs enough from the other end to deserve another name And I that but related a Phaenomenon did not perhaps express my self much less warily if not more so than Mr. Hobbs himself For whereas my words are these We presently took out the Coals in which it seems there had remained some little Parcels of fire rather covered than totally quench'd for in the open air the Coals began to be rekindled in several places Mr. Hobbs even in his Elements of Philosophy speaks thus upon a somewhat-like occasion If a Grate filled with Coals throughly kindled and burning never so brightly be let down as soon as ever it is below C. the fire will begin to grow pale and shortly after loosing its light be extinguisht no otherwise than if it were quencht in water but if the Grate be drawn up again presently while the Coals are still very hot the fire will by little and little be kindled again and shine as before As for the reason Mr. Hobbs assigns of our Experiment in the lately mentioned passage of his Dialogue being grounded upon such a thickness of the Air in the Receiver as we have already disproved it needs not to be examined And lastly as to what he subjoynes in these words Quando autem est quod de homine vere pronunciare possumus quod est mortuus sive quod idem est animam expiravit Cognitum enim est homines nonnullos pro mortuis habitos postridie elatos revixisse A. De puncto temporis quo anima à corpore separatur difficile est statuere Perge igitur ad experimenta alia I confess I see not why that needless Question might not have been well spared if he designed to give it no better Answer CHAP. VI. Wherein other passages of Mr. Hobbs's Dialogue that concern the Author are examin'd WHat our Author has in the 19. page concerning a Bladder has been already examined wherefore I proceed to the next passage in the same page which is this B. Si acus magnete excitus libere pendeat intra Recipiens sequetur tamen ille motum ferri quod circumducitur extra Recipiens Item object a intus posita ab iis qui extra sunt videbuntur soni intus facti audientur omnia haec aeque post atque ante exuctionem aëris nisi quod soni sunt aliquanto post quam ante debiliores A. Manifestissima haec sunt signa Recipientis semper pleni nec posse inde exugi aërem Quod autem soni inde sentiantur debiliores signum est consistentiae aëris Consistentia autem aëris à motu ejus est per lineas diametraliter oppositas But I meet with few of the Vacuists who even in the Torricellian Experiment think the place relinquished by the Quicksilver to be perfectly void most of them allowing that though it be not quite full of body yet it may contain some of the Earth's magnetical steams or of those igneous Corpuscles that flow from the Sun or both of them Now against these who would from our Experiments deduce but onely an interspersed Vacuum I see not that the Phaenomena mentioned by Mr. Hobbs do conclude half so manifestly as he pretends For as to the motion of the Needle within the Receiver 't is known that they are wont to ascribe Magnetical Attraction to certain Effluvia that issuing out of the Loadstone are subtile enough to pass through the Pores of the closest bodies without excepting Glass so that although the Receiver were quite empty'd before the Needle might be wrought upon by Magnetical Corpuscles that need not be supposed to fill the 10th part of the Receiver I know indeed that Mr. Hobbs has another Hypothesis of the Phaenomena of the Loadstone but I know that divers learned Writers have absolutely rejected it and not one such that I have heard of has approved it And as for the other two Phaenomena here mentioned by Mr. Hobbs the Atomists may answer That the first touching Objects seen in the Receiver has been shewn already not to overthrow their Doctrine and that the other concerning the Debilitation of Sounds makes against him not for him since we have already disproved that consistence of the Air whereto he ascribes it And the same Arguments that overthrow that Opinion may make it seem somewhat strange that he should subjoyn our Experiment of two like Pendula whose Vibrations we found not manifestly to differ within and without our exhausted Receiver For the former should move far slower than the other according to Mr. Hobbs's Conceit that the Receiver when we say 't is exhausted is filled with a substance of a middle consistence betwixt pure Air and Water and not much lighter than Water But whether the Receiver be in such cases adequately full or no the Vacuists may further consider For its being granted to be full would not overthrow either of my Hypotheses namely the Weight and Spring of the Air. In the same 19. and some following pages Mr. Hobbs has a long Discourse against my Conjecture at the reason I propose in my 31. Experiment why as I there express it if the exquisitely polisht Surfaces of two flat pieces of Marble be so congruous to each other that upon their mutual application there results an immediate contact they will stick so fast together that he that lifts up the uppermost shall if the undermost be not exceeding heavy
I may answer For not to mention that the Argumentation is invalid unless by Fluidum he mean Omne fluidum I reply That till he have explained what he means by his Fluida prima and proved that there are such the Question needs no Answer Besides that whatever he upon mistakes strives to infer my Doctrine is so far from affirming that there are many parts of matter of which neither fluid nor hard bodies can be made that I teach as we have lately seen that there are multitudes of parts that may by being reduced to a sufficient smalness and put into a convenient motion or by being brought to a mutual contact and rest be made to constitute either a fluid body or a firm one as may be exemplified in the formerly-mentioned instances of two subtile liquors that immediately composed a consistent body and of Quicksilver which without additaments was made sometimes a Powder and sometimes a liquor What Mr. Hobbs addes in the next page about the difficulty of explaining the Diaphaneity of Glass or Crystal in case they consisted of Corpuscles hard and implicated or having their Pores in any way whatsoever disjoyned I must not now insist on since besides that such a disquisition would require almost a Volume the true and general cause of Transparency in bodies is in my poor Opinion one of the abstrusest things in Natural Phylosophy and Mr. Hobbs's Explication of it though none of his worst Conceits has for ought I can find fallen short of satisfying the Curious as well as those of other men have done But to me that have not taken upon me to write Elements of Phylosophy it is enough that I have by competent Experiments and other Proofs confirm'd the truth of my Doctrine about the cause of Firmness though I attempt not to explicate the other qualities of the same bodies whose Explication my undertaking does not exact Wherefore I hope I may now hasten to conclude this Appendix with spending a few words on the Notion of Fluidity and Firmness Mr. Hobbs would substitute instead of mine For having now perhaps but too prolixly examined what he has been pleased to object against my doctrine I shall not need spend time to vindicate the Experiments and Considerations whereon I built it Mr. Hobbs for reasons best known to himself not having thought fit to take notice of them Mr. Hobbs's Theory of Fluidity and Firmness is thus delivered by himself B. Quaenam duri fluidi sunt principia A. Quid aliud nisi fluidi quidem Quies duri autem Motus quidam ad illum effectum producendum idoneus Per Quietem intelligo duar am partium inter se quietem cum se mutuo tangunt quidem sed non premunt Nam fluida moveri tota possunt retenta fluiditate dura quiescere ut tamen partes eorum moveantur I doubt not but this will to most Readers seem a Paradox And as for his Ratiocination contain'd in the two last lines I shall readily allow him that Fluida moveri tota possunt retent a fluiditate since that I think agrees at least as well with my Hypothesis as his but whereas he adds that hard bodies may rest and yet their parts be moved that may in one case be conceived and in another not For indeed the implicated parts of a firm body may be made to tremble or a little vibrate as it were to and fro as those of a sounding Bell do or as in a Hedge the branches and twigs may be shaken by the wind whilst the trees and bushes themselves continue rooted in the ground But that in a body the constituent Corpuscles should all or most of them be moved quite out of their places in respect of one another as was lately shewn to happen in fluids and yet the body continue hard is more requisite than easie to be proved But Mr. Hobbs contents himself to alledge in favour of his strange Notion touching Fluidity and Firmness three particulars which I confess afford me not the least satisfaction The first is drawn from what he formerly taught touching the swift motion of the Air in our Cylinder which example as he calls it having repeated he adds Atque hinc manifestum est vehementem esse in aëre it a moto clauso compressionem quantam scilicet efficere potest vis illa qua incussus erat atque etiam à tanta compressione aliquem gradum consistentiae fieri quanquam consistentia aquae minorem Quod si esset in iisdem particulis aëris omnibus praeter motum illum quo alter a alteram premit motus ille circularis simplex isque satis vehemens impossibile fere esset unam earum à suo circello dimoveri quin reliquis particulis resistentibus totus simul premeretur idest totum durum esset durum enimest totumillud cujus nulla cedit parsnisi cedente toto Vides ergoposse fieri duritiem in fluidissimo aëre per motum hunc circularem simplicem particularem quibus duo motus contrarii ante dederant vertiginem But I confess I do not see how the Motus circularis simplex he talks of should give such a hardness to the fluid Air nor is it manifest to me how the Air that perfectly fills the Cylinder can be by motion compress'd especially so far as to obtain thereby a degree of consistence fit to be mentioned as he speaks of it when without adding the word much or any other equivalent term he sayes that yet 't is less than the consistence of water For the Cylinder being according to him perfectly full of Air I see not how the Pumping can make the Cavity to use his own expression elsewhere fuller than full nor consequently can compress the Air to a consistence any thing near that of water without penetration of Dimensions But these things were mentioned onely ex abundanti for the violent motion it self of the Air in the Cylinder which motion the Argument supposes has been already in the Examen of one of the former passages of his Dialogue sufficiently manifested to be contrary to Experience The second thing Mr. Hobbs alledges is his Conceit of the Generation of Flesh within the Muscles of the humane body But besides that he takes for granted two or three things which many learned Anatomists and Physicians even among the Moderns will scarce allow him and which he does not prove besides this I say which I may elsewhere have occasion to consider further the account he gives of the Generation of Flesh from these suppositions is far from being evidently enough deduc'd to vie for clearness with many of those Experiments which I have alledged in favour of the Opinion he opposes And whereas he adds Atque talis quidem esse potest causa efficiens Duri primi Duri autem secundi id est Duri à cohaesione durorum primorum causa potest esse motus ille idem circularis simplex conjunctus cum contactu
finding out of the invisible causes of natural things all will be in vain p. 15. Cum ejus c. Seeing almost all its parts are flexil like little soft feathers to fine threds Ibid. Sed quisquis c. But it matters not who was the Author of that Supposition For the very Hypothesis it self wherein is supposed a motion of subtil matter which is swift without any cause assigned and hath moreover divers innumerable circulations of Corpuscles generated from the single motion of that matter is not the conceipt of a man of wit or sense p. 16. Nempe hoc c. This is the thing that the great Des-Cartes somewhere admired that he whether his Positions are true or false doth never in argumentation make any right inference from his Suppositions p. 17. Quod sane c. Which is indeed a most evident argument of the weight of the Air. Ibid. Quod quidem lanx c. That the Scale in which the Bladder is is more deprest than the other they may be certain their eyes bearing them witness but that this comes from the natural gravity of the Air he cannot be assured especially if they are ignorant what is the efficient cause of Gravity p. 18. Quod vesica c. That the Bladder whether it be blown up with a pair of Bellows or with the breath of ones mouth is heavier than when it is not blown up I will not deny because of the greater quantity of Atoms from the Bellows or of fuliginous Corpuseles that are blown in from the breath But notwithstanding they gather nothing of sufficient certainty from this Experiment of a blown Bladder They ought to have put into the Scales two Vessels of equal weight whereof one should be shut and the other open For by this means Air not blown in but onely inclosed had been weighed When therefore you shall see Air so weighed we will afterwards consider what may be said concerning the Phaenomenon you bring p. 19. Quod Atmosphaerae c. That many Particles both of Earth and Water mingled with the AEthereal body are in the Atmosphere I am easily persuaded but that in the middle of the AEther they should move upwards downwards every way and that one leaning on the back of another they should not gravitate is a thing utterly unconceivable p. 20. Aer quo c. The Air with which in the beginning the Spherical Glass was full being moved by those Earthy Corpuscles in a simple circular motion and being comprest by the force of the Injection that of it which is pure penetrating the injected Water gets out into the open Air and gives place to the Water It follows therefore that those earthy Corpuscles have less place left in which they can exercise their natural motion therefore beating one upon another they force the water to go out it thus going out the external Air because the Universe is supposed to be full penetrates it and successively takes up the place of the Air that goes out until the Corpuscles the same quantity of Air being restored regain a liberty natural to their motion p. 21. Quoniam per c. Because by the drawing back of the Sucker the pure Air was thrust in but the earthy parts were not thrust in there was a greater proportion of earthy Particles which without the Cylinder were near the Sucker unto the pure Air in which they exercised their motion as well after this revulsion as before Wherefore these Particles so moved having less place to exercise their natural motion in some of them fell foul and beat upon the rest So that of necessity the Particles that were near the surface of the Sucker must drive it upwards Ibid. Vidisti c. You see now that the Spring of the Air which they fuppose is either an impossible thing or they must for its defence have recourse to the Hypothesis of Mr. Hobbs p. 23. Quia cuticula omnis c. Because every skin is made up of small threds or filaments which by reason of their figures cannot accurately touch in all points The Bladder therefore being a skin must be pervious not onely to Air but to Water also as to sweat Therefore of the Air beat in by force there is the same compression within the Bladder that there is without The endeavour of which the way of its motions being every way cross tends every way to the concave superficies of the Bladder Wherefore it is of necessity that it must swell every way and the vehemency of the endeavour increasing be torn at last p. 26. Intellexti c. Have you understood my Hypotheses 1. That there are with the Air intersperst many earthy Particles endued with a simple circular motion congenite to its nature 2. That there is a greater quantity of these Particles in the Air that is near the Earth than in that which is more remote from it p. 27. Neque est c. nor is there any one that hitherto has brought any reason why it may not be so p. 29. Nihil c. Nothing is moved but by a contiguous Body that is in motion Ibid. Dum Suctor c. While the Sucker is drawn back by how much a greater place is left within by so much a lesser place is left to the external Air which being thrust backwards by the motion of the Sucker towards the outmost parts doth move in like manner the Air that is next it self and that Air the next and so forwards so that it is of necessity at last that the Air must be compell'd into the space deserted by the Sucker and to enter between the convex and surface of the Sucker and the concave of the Cylinder For it being supposed that the parts of the Air are infinitely subtil it is impossible but they should insinuate themselves that way by which the Sucker is drawn down For first the contact of those surfaces cannot be perfect in all points because the surfaces themselves cannot be made infinitely smooth Then that force which is applied to draw back the Sucker doth distend in some measure the cavity of the Cylinder Lastly if in the confines of that is betwixt the two surfaces any one single hard Atom should enter pure Air will enter at the same way although with a weak endeavour I might also have accounted that Air which for the same cause insinuates it self through the Valve of the Cylinder You see therefore the consequence from the retraction of the Sucker to the being of an Empty place is taken away It will follow also that the Air which is driven up into the place deserted by the Sucker because it is driven up thither by a great force is moved with a very swift and circular motion betwixt the top and the bottom in the Cylinder because there is nothing there that can weaken its motion and you know that there is nothing that can give motion to its own self or diminish it p. 39. Haerent hic
some place empty to prove that a Vacuum is possible if full they say that is full which they suppose to be empty p. 56. Fuere c. There were some of them that said there remained in those coals though they seem'd extinguish'd some fiery Particles which being blow'd up by the Air upon its admission did re-kindle the rest of the mass Ibid. Nae c. In good faith they seem not so much as to have considered what they should speak as to have taken it up at all adventures Do you believe that in a kindled coal there is any part which is not a coal but fire or in a red-hot Iron there is any part that is not Iron but Fire A great City may be set on fire by one spark Now if the body of fire be different from the thing fired there can be no more parts of fire in the whole Town on fire than that one spark We see bodies of divers kinds may be set on fire by the light of the Sun as well by the Refraction as the Reflexion that is made in Burning-glasses And yet I do not believe that there is any man thinks that Particles of fire darted from the Sun can pass through the substance of a crystal Globe And in the Air between the Sun and the Globe there is no fire p. 58. When is it that we may truly say of a man that he is dead or which is the same hath expired his Soul For it has been known that some men who have been taken for dead being brought out the next day revived A. It is hard to determine the point of time in which the soul is separated from the body Proceed therefore to other Experiments p. 59. Si acus c. If a Needle excited by a Loadstone hang freely within the Receiver it will nevertheless follow the motion of the Iron which is drawn about without the Receiver So objects put within will be seen by those that are without and sounds made within will be heard without all these as well after as before the exsuction of the Air except that the sounds are somewhat more weakly heard after than before B. These are most manifest signs that the Receiver is alwayes full and that the Air cannot thence be suck'd out That the sounds thence are more weak to ones hearing is a sign of the consistence of the Air for the consistence of the Air is diametrically opposite from its motion p. 61. Quia nihil c. Because there was nothing there that the weight of the Atmosphere should do no more strong or evident Argument could be made against a Vacuum than this Experiment For if of two coherent Marbles either of them should be thrust forward that way that their surfaces lye contiguous they would easily be sever'd the neighbouring Air successively flowing into the deserted place But so to pull them asunder that at one time they should lose their whole contact is impossible the world being full For then either motion must be made from one term to another in an instant or two bodies at the same time must be in the same place to say either of which is absurd p. 62. Confitentur c. They themselves and all others confess that all Ponderation is an endeavour every way by right lines unto the Centre of the Earth and so that it is made not by the figure of a Cylinder or Column but by a Pyramide whose top is the Centre of the Earth and whose Basis is part of the surface of the Atmosphere Ibid. Conatus c. Therefore the endeavour of all the points that ponderate will be propagated to the surface of the upper Marble before it can be propagated further suppose to the Earth p. 64. Has c. These Scales he puts one upon another and draws out the Air and then are they kept so comprest and united by the gravity of the external Air that six strong men cannot pull them asunder But if at length by the use of utmost endeavour they are pluckt in sunder they make a noise equal to the report of a Musquet but as soon as ever by the Stop-cock open'd there is the least entrance given to the Air they are severed of their own accord p. 65. Sed vis c. But can the Spring which they say is in the Air confer nothing to the holding up the Marble Nothing at all For there is no endeavour of the Air to the Centre of the Earth more than to any other point in the Universe For seeing that heavy things tend from the circumference of the Atmosphere unto the Centre of the Earth and thence again to the circumference of the Atmosphere by the same reflected lines the endeavour upwards will be equal to the endeavour downwards and so destroying one another they will endeavour neither way p. 66. Non potest ergo pars BC c. Therefore the part BC that is a part of the Atmosphere placed any where within the whole cannot by reason of its greatness descend although it be heavy and therefore it cannot press or gravitate Ibid. Si possibile c. If I should deny it possible that by the art of man two furfaces of two bodies could be made so accurately fit that they should touch in all points so that there could no creable Corpuscle pass between them I do not see how they could defend their own Hypothesis or disprove our Negative assertion Ibid. Vtraque c. Both these Fancies as well that of the Weight as of the Spring or Antitupy of the Air are Dreams But if it be granted that there is a kind of Recoyling in those small hairs or slender Corpuscles of which the Air consists one may enquire whence it is that those crooked bodies settled and at quiet in that posture came to be moved into a streightness They ought if they will be esteemed Natural Phylosophers to assign some possible cause of this p. 67. Cur non c. Why cannot the water which when it was injected did compress the particles of Air be again cast out by the same particles explicating themselves A. Because when explicated they require no greater place than when comprest As in a vessel full of water wherein are many Eeles the same proportion of place receives them whether they are folded round or at length Therefore they cannot drive up the water by their Spring which is nothing else but the motion of bodies explicating themselves B. The comparison of Air to Eeles in water I suppose will be well received by our Academians p. 68. Vides c. You see how foolish a thing it is to bring for the explication of such effects Metaphorical words as the shunning of a Vacuum the ahhorrence of Nature c. which heretofore the Schools used to defend their reputation Ibid. In the Gardeners Watering-pots therefore is the water suspended because that which issues out at so small a hole is so little that it cannot diffuse it self to