Oeuvres complètes. Tome IV. Correspondance 1662-1663
(1891)–Christiaan Huygens–
Auteursrecht onbekendNo 1056.
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[pagina 218]
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hausted his partiality for my writings, since he is pleasd to make you such a mention of my lastGa naar voetnoot5) that J can much better resent & blush at then deserue, which you will obleige me to let him know the next time you write to him. But because J presume you & perhaps he may expect that J should say something to the particulars in my book on which he animaduerts, especially since his objections are soe few, as well as soe judicious, that as they highly deserue a serious reflection, soe J may giue you my thoughts of them in this couer wherein J inclose you his letter. J shall take notice to you in few words (hauing not now time to trouble you with many) that ye particulars in Monsieur Zulychem's letter that require to haue something sayd to them by way of answer, are these fowre. The first is my hauing made such solemn Answers to my two aduersarys Linus & Mister Hobbes whose arguments he is pleasd to speak soe slightingly of. But though to this J might represent that J could not hope to finde many readers that understood those controuersys half soe well as Monsieur Zulichem, And though J might adde what els J say in the prefaces & beginnings of ye books them selues, to giue an account of my proceedings, Monsieur Zulychem's Ciuility has furnisht me with an answer, that J should not els haue made vse of in saying that he finds J haue done what jndeed J indeauourd to doe, bye taking occasion from the objections J answerd to offer somethings to the Reader, towards the further illustration of ye Doctrine it self of ye spring of ye air. As to what he sayes touching the hypothesis assumed to make out the phaenomena of Rarefaction, it will not be requisite for me to inlarge vpon it, the ProposerGa naar voetnoot6) of the Hypothesis being himself ready to giue you an account of it. And Monsieur Zulichem though (cheifly through the Printers fault) he mistakes the proposer of it, yet rightly apprehends both that the Hypothesis is plausible enough, and that tis propos'd but (as his letter speakes) as a project or a possible way of soluing the phaenomena of Rarefaction without hauing recourse to the vnintelligible way of Aristotle. Of the two other & more important particulars, that Monsieur Zulychem objects, the first you know is that he conceiues not either by Linus his hypothesis or ours there can be a sufficient Reason rendred, why in the Torricellian Experiment, the finger that stops the orifice of ye tube when it has neer 29½ inches of Mercury, should lift it vp & stick soe close to it as to need some force though but a litle to seuer it from the Orifice. But here J first take notice that he judiciously obserues, that the difficulty to explicate this phaenomenon is as great in our aduersarys | |
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hypothesis as in ours. Next you may remember that in my book J inform'd you, that vpon seuerall tryalls we could not finde the experiment to succeed, Nor does Monsieur Zulichem mention it as a thing duly tryed, by him self or any of his freinds. But howeuer let vs in the third place consider whether the phaenomenon if granted sometimes to happen may not be well enough solued by our hypothesis. For Monsieur Zulichem as A person that very well vnderstands it, does himself allow that (to vse his words) the finger being prest from aboue (Let me add & laterally too) by the weight of ye atmosphere & ye Mercury from beneath, they ought for this reason to continue joynd together. Now jn case it happen as it often does without being heeded, that ye glass being vnequally blown the orifice contiguous to ye finger be broader then the rest, the atmosphericall cylinder that presses against the finger will haue a greater Diameter then ye Mercuriall, And consequently be able to sustein a greater weight. But setting aside this case if the pressure of ye air can sustein a cylinder all of Mercury whose height is 30 inches, it may well be conciued to be able, more then barely to sustain such a Cylinder, in case part of it be not of Mercury, but of a farr less ponderous body of glass whose weight by comparing it with exact schales we sinde to be to that of the water of the same bulk as 1 to 2⅔Ga naar voetnoot7). And consequently its weight to that of Mercury is as 1 to 5¼. not now to examine whether & how far the close adhesion of the finger to the tube may be promoted by the spring of ye pulp, thrust into the deserted part of the tube, and there expanding it self, as J haue osten obserued the parts of liuing creatures to doe in our exhausted Receiuer. The Last thing which Monsieur Zulichem sindes a Difficulty in, being the same which he also formerly proposdGa naar voetnoot8), is that shutting vp in the Receiuer a short glass tube filld with water, and inuerted into a jar containing some of the same liquor, if it were common water it would vpon the exhaustion of the Receiuer subside in the tube or rather be deprest by the expansion of the aeriall particles latitant in the water. But in case the water were before the operation freed from such aeriall particles then noe pumping would make it subside. The experiments in tubes of 5 or 6 inches J haue seuerall times made which lessens not my resentment of Monsieur Zulichem Fauour in imparting it to me. But J confess J am still of ye opinion which you may perchance remember that J proposd some monthes agoe in our Assembly of Gresham Colledge. For Monsieur Zulychem indeed does as he is wont argue very rationaly, wher he concludes this to be a capitall difficulty. But his whole reasoning is built vpon supposition that the Receiuer is quite void of air, and that he collects from his not being able to pump out any more. But we | |
[pagina 220]
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must confess that hitherto we haue not been able to bring our engine to that passe as to free it perfectly from air, though we now make vse of one whose pump being vnder water is probably lesse subject to leake then Monsieur Zulichem's, though otherwise J question not but very exact as can be. Yet hauing purposely made tryalls in short pipes with Quicksiluer in steed of water, we vnwillingly found, that if we first freed it from air, we could scarce make it subside in the tube soe low as within half an inche or thereabouts of the surface of the externall mercury. Soe that if the pipe had been silled with water freed from air, that litle air that yet remained in the Receiuer, would haue kept it from descending, though the aqueous cylinder had been 7. or 8. inches high. And jn case our care & diligence had been less or our pump had not been placed vnder water to keep it more stanch tis very likely that there would haue remaind air enough to keep vp a cylinder of water of at least twice or 3 that length. These Sir are my present thoughts concerning this phaenomenon, which J offer you with ye less scruple because they question not Monsieur Zulychem's Ratiocination, but only the stanchness of his pump, And will J presume appear allowable, til a far more perfect exhaustion of the Receiuer can be cleerly made out. Yet J would not bye these conjectures diuert either him or my self from further inquirys. For though the hypothesis it self of ye spring of ye air, be J hope sufficiently establisht: yet by reason of the peculiar texture of some bodys, or some vnheeded circumstances there may happen some odd phaenomenon or other, very difficult to be accounted for, As J obserue in the Experiment concerning ye permanent expansion of Spirit of Wine. But my hast forbids me add any more to your trouble, saue that renew'd request that when you write to Monsieur Zulychem you would assure him of my recentment of the fauour of his letter and especially of ye part of it that conteines his animaduersions, which comming from such a one as He, cannot be vnwellcome to a person who knowes how much fitter for him 'tis to be instructed, then applauded. And if in this paper you finde your self any thing of scruple, you may command my jndeauours to remoue it at your next being waited on by
Sir
Your most affectionate & most humble seruant Ro: Boyle.
My hast made me forget to returne my humble thanks to Monsieur Zulychem for what he offers about the experiment to be made at Westminster. |
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