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

TITLE XIII. Experiments and Observations concerning the Sphere of Activity of Cold.

* 1.1IN estimating the Sphere of Activity of Cold, we are not only to consider the Degree of it in the cold Body; but also the Medium through which it is to pass, and the Consistence and Texture of it; as likewise the Instruments em∣ploy'd to receive or acquaint us with the Action of Cold: Since, from what hath been before laid down, it appears, That Weather-glasses give us a more nice account of the Degrees of it; and that our Sensories may mis-inform us, upon the ac∣count of their various Predispositions. Besides the Sphere of Activity may be vary'd by the Bulk of the cold Body.

1. But to consider the Sphere of Activity of small Pieces of Ice; we have found it very small in comparison of the Atmospheres of odo∣rous Bodies; insomuch that I am perswaded, we can have no sense of Cold, without the im∣mediate Contact of a cold Body; since Ice ap∣proaching our Sensory, or a Weather-glass, af∣fects neither; tho' held as near as possibly they may without touching. And the like hath been

observ'd at Sea, where in foggy Nights the Sea∣men have not been able to discern neighbouring Mountains of Ice: Tho' by a Merchant who made the Observation in Greenland, I am told, That he perceived a manifest access of Cold, upon the approach of a floating piece of Ice.

2. And I am told, that in Ispahan the Capital City of Persia, the Ice being never much more than a Finger thick, they usually pour Water upon it, which as it runs over the Ice, is in part froze, by which means, they thicken the Ice, and preserve it in proper Conservatories. This Experiment having been tryed in England, by pumping of Water upon Flakes of Ice; I found, That the Pump-water, being warmer than the Ice, thawed it, instead of increasing the Thick∣ness of it. And tho' here in England, Water poured upon Snow promotes its Dissolution, yet in Russia and Muscovy I am told, That Water thrown upon Snow freezes it; which they there∣fore make use of to incrustate several Bodies with Ice; yet one thing is to be observ'd, that gene∣rally at the same time, the sharpness of the Air is so violent, as to incrustate several Bodies with Ice, when only Water is made use of; so that in trying such Experiments, we are to consider the Temperature of the Air at the same time, which hath a great Influence in promoting or va∣rying the Effects of such Tryals.

3. How deep Frost penetrates into Water and Earth will be a very hard thing to determine; since Earth especially, may be more or less dispo∣sed to freeze, according to the several Degr••es of Cold, and its Duration; the Tex•••…•••… of the Earth, and the Nature of the Juices d•••…•••…ed

through it, or subterraneal Steams: Whence large Tracts of Land that lye over some Mines, are always free from Snow, good quantities of Lime∣stone being near the Surface of the Earth.

4. But tho' it be so difficult to know to what Depth Frost will reach, yet that we may contri∣bute as much as we can to the general History of Cold, we shall add the following Notes. Af∣ter four Nights hard Frost the Ground in the Orchard was froze about 3 Inches deep, and in the Garden about 2; after ten Nights Frost, the Ground in the Garden was froze about 6 Inches ½, and that in the Orchard was froze 8 ½ or more. Eight Days after, it was froze about a Foot Deep.

5. A Pipe of Glass 18 Inches long being thrust down into a Hole in the Ground, the Surface of the Water contained in it being level with the Earth; the next Morning the whole Capa∣city of the Cylinder was froze 3 Inches, from which Stick of Ice a Part of the Cylinder was froze 6 Inches deep; but the rest of the Water remained unfroze: The Ground in the Garden, that Night was froze ten Inches deep.

6. It hath been observ'd, that in Moscow the Ground in a Garden was not froze above two Foot deep; but Capt. James says in Charlton-I∣sland he observ'd the Ground froze ten Foot deep; and the same Author in his Journal, p. 86. says, That the Water does not freeze naturally above six Feet.

One Particular referrable to the XIII Title:

I am told, That a Lee-ward of great Banks of Ice, they may discover them by the access of Cold, twenty Leagues.

Notes

• * 1.1

  Of the Sphere of Activity of Cold.