The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

TITLE XIV. Experiments concerning the Different Medi∣ums through which Cold may be diffused.

* 1.1IN trying these Experiments we are to take Notice, that the Mediums are not to be too thick; since, from Experiments already deliver'd it appears, That a compact Medium very thick will not give way to Cold.

1. Having placed a Mixture of Snow and Salt in a Pipkin, and another in a white Basin glazed within and without, they were both incrustated with Ice. And that Cold will penetrate Pewter-Bottles, appears from Experiments already laid down.

2. Having caused two Cups to be made of Lattin, or Plates of Iron covered over with Tin, the Convex Part of one of which, was less than the Concave of the other; and the less having a broad Ledge, by the help of which it rested on the Brim of the other, so as to leave an Interval betwixt its Convex Superficies and the Concave of the other; we filled that Interval with Wa∣ter, and putting a Mixture of Ice and Salt with∣in the less Cup, and on the outside of the other, we had Cups of Ice made of the inclosed Water.

2. The Learned Erasmus Bartholinus in his discourse De figura Nivis mentions an Experi∣ment by which Air is turned into Water in the midst of Heat, viz. Ice or Snow being put into a a funnel; which he supposes refrigerates and condenses the Ambient Air; but I rather think, That the Dew which he supposes to be condensed Air, is made up of moist Vapours swimming in it; which is so small in Quantity, That having suspended a Tunnel in the Air, with a Mixture of Snow and Salt; which is much more refrigerating than either Ice or Snow by themselves, it gathered but a very small Quantity, and that too lasted no longer than whilst the Mixture was dissolving; besides those condensed Vapours were first Froze before they dropped down in the form of Water.

3. That in Hermetically sealed Glasses, a Mixture of Snow and Salt will freeze Vapours on the outside, is evident, from what hath been laid down; but that Cold should not only penetrate Glass, but afterwards act upon Water in Vacuo; was a little more strange: For having suspended a Tube of Water in Vacuo and pi∣led Snow and Ice about it, as high as the In∣cluded Water wrought; it worked upon it, and Froze it from the top to the bottom.

4. But what is yet more strange is, That Cold will act through a evidently hot Medium; for drinking a good quantity of Mineral Waters timely in the Morning, I observ'd a Manifest Coldness through the Muscles of my Abdo∣men, which was in a higher degree remarkable in a Gentleman who drunk much greater quan∣tities.

5. To try whether the fluidity of Water depended on a Congenite motion in the Parts of it, or whether it was conveyed to it by impulse from the Ambient Air; we provided a Glass-Bubble about the size of a Wall-nut and of a Pear like shape, whose Stem was purposely made crooked, and suspending it by a thread in Oyl of Turpentine contain'd in a narrow Glass; and this being placed in a Mixture of Snow and Salt, tho' the Oyl continued fluid; yet the Water in the Bubble was froze. And when we went to take it out, the Bubble being crack'd, the greatest Part subsided to the Bottom of the Mixture; but we per∣ceiv'd, That, that which was pulled out, was divided by a line through the middle from the top downwards. And it was further observa∣ble in this Tryal, That the two separable Piec∣es of Ice, being left in a Mixture of Ice and Salt for 14 hours, were very little wasted. The like success we had with a Bubble of Water suspended in Spirit of Wine; but another sus∣pended in Sea-Salt was not froze at all; nor was another that we hung in a sharp brine: But the same Experiments being tryed another time; the Water was froze both in the Bubble suspended in Spirit of Wine, and in that which was immersed in the strong Brine; the Bottle which contain'd the latter being crack'd, which cracks were not much unlike the lines drawn from the Pole of a Globe to the Meridi∣an; reaching from the top of the Bubble down∣wards.

6. A Bubble suspended with Water in it, in a Glass immersed in Snow and Salt, was froze, without the Intervention of any Li∣quor.

Notes

• * 1.1

  Of the Me∣diums through which Cold may be dif∣fused.