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

An Appendix to the XVII Title.

* 1.1Bartholinus citeing an Experiment, wherein the Proportion betwixt Nitre and Water was 35 to 100; to try the success of it, we mixed a Pound of Salt-Petre with 3 Pounds of Water, and stirring it about constantly, as Cabaeus directs, in an Hour and half we perceived not the least Ice; whereas, according to him, it ought to have been wholly froze in less time; but we could not perceive the Vapours on the outside of the Glass in the least froze.

For a further Tryal, we mixed two Ounces of Salt-Petre with six of Water in a Glass-Vial, but by all the shaking we could not produce the least Ice; tho' whilst the Nitre was dissolving the Mixture was sensibly colder; and the same we have observ'd to happen upon a Dissolution of Common Salt; tho' the Degree of Cold was not sufficient for Congelation, which I was satis∣fyed in, by removing a Thermoscope out of the Mixture of Nitre and Water, into Water which was placed in Snow and Salt: For by that means the Liquor in the Weather-Glass subsided in the latter about 3 Inches; so that I am apt to think

the Learned Cabaeus mistook Chrystals of Nitre for Ice.

It is believed by most Water-men, That the Water begins to freeze at the bottom, because they observe large Pieces of Ice rise from the bottom of the Water: But the Truth of it is very reasonably question'd, since we not only see, that Water in Vessels, but in Wells, begins to freeze at the Top; and several Arguments in proof of the contrary may be found in our Section of the Primum frigidum. And as for those Pieces of Ice, which they observe to e∣merge, that Phaenomenon may easily be solved, without supposing the Water to begin to freez at the Bottom: For since the Water, which runs along the sides of the Banks being froze, seve∣ral Stones may stick to it; they by their Weight may cause it to subside, when it is partly loos∣ned by the Heat of the Sun, and the Water, by that Rarifaction becomes lighter: Yet, when the Water above is cooled, and the Water be∣low being warmer, hath melted the Ice in some measure, and loosned some of those Stones which were before froze to it; the Ice becoming speci∣fically lighter than the Water, must consequent∣ly emerge. On which occasion, I shall here ob∣serve, that Capt. James Hall takes notice, That they found a Stone of three hundred weight upon a Piece of Ice. In confirmation of our Solution of this Phaenomenon, I might al∣ledge the Experiments laid down in the Section of the Duration of Ice. And it were to be wish∣ed, that for a further Decision of this matter, that either Divers were sent down, or Instru∣ments

which would bring up Ice if any were there.

We took a seal'd Weather-Glass, and having inverted the Stem of it when furnished with Spirit of Wine, so that, that being placed in a Hole purposely made in a Box, the Ball of the Weather-Glass rested on the Box; about that we placed a Mixture of Snow and Salt, and found, that presently the Spirit of Wine was retracted. So that Liquors may be condensed, without the assistance of their Gravity, to de∣press and cause the Parts of the Body to sink to∣gether: But whether in this case, the Contra∣ction was assisted by the Tenacity of the Liquor or the Springiness of some Elastick Particles, will be inquired into in a more proper Place.

Frogs and Toads being taken up from under Ice, were brisk and lively; and it is observ'd, that in frosty Weather they generally lye in the Bottom of Pits, for their Security.

Notes

• * 1.1

  Of the Ef∣fects of Ni∣tre in free∣zing.