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

TITLE X. Experiments about the Measure of the Expan∣sion and the Contraction of Liquors.

* 1.1TO measure the expansion of the Air, we took a Bolt-head, and pour'd in so much Water, that it rose a little way into the Stem; which being done, and the number of Ounces it contain'd set down, to those we successfully ad∣ded one Ounce after another; marking how high each of them wrought: Which being done, we pour'd out a convenient quantity, and froze the remaining Water from the bottom upwards, and the Ice that consisted of 82 parts of Water, filled the space of 91 and ½; so that the congeal'd Water possess'd a 9th part of space more than it

did before. In another Experiment 55 Parts of Water being froze, were extended to 60 ½; 6 of those remaining unfroze.

2. Another way we took to measure the ex∣pansion of Water, was, by marking a Cylindri∣cal Pipe at the superficies of the Water contain'd in it; which, when it was froze, was rais'd a tenth part higher than before. Another more exact Cylinder being made use of, we found, that Water froze expanded to about a ninth Part of the space it possess'd before.

3. But perhaps this Method of measuring the expansion of freezing Water may suggest a diffi∣culty to those that are acquainted with Hydrosta∣ticks: since Archimedes hath made it appear, as well as Stevinus, That floating Bodies will so far, and but so far, sink in the Liquor that supports them, till the immersed Part of the Body be equal to a bulk of Water, weighing as much as the whole Body.

4. For Capt. James hath observ'd Ice to float a great deal above the Water; and the Hollan∣ders in their Voyage to Nova Zembla, take no∣tice of a Hill of Ice which was 16 Fathom above the Water, tho' but 36 below it: And Janus Munkius in his Account of G•…•…enland, observ'd, That one that was but 4•• Fathom under Wa∣ter, was 20 above it; whereas according to our Computation of the expansion of Water, the Part under Water ought to be 8 or 9 times as deep as that above it.

5. But to clear this difficulty I have these things to represent; First, That the Ice which we take notice of, floats in fresh Water, but that observ'd by Navigators, being fresh floats in salt Water; yet this is to be likewise consider'd, That near the Poles the Seas are not so salt as ours, or

those under the Line, and consequently will not be able to bear up the floating Ice so high; except the coldness of that Region recompenses the want of Salt.

6. But besides these Considerations, that which I would chiefly insist upon for the removal of this difficulty, is, That these huge Piles of Ice are made up of vast Lumps, betwixt which are large Vacuities which are only fill'd up with Air; so that we are not to judge of their weight by the bulk they appear to be of to the Eye; but by the specifick weight incumbent on that part immers'd in the Water: For we see in Barges, that sometimes they carry Loads, which consist∣ing of light Matter, may be piled a great height above the Water, without depressing the Vessel so much as heavier Bodies of less bulk, which are more ponderous in Specie; for the greatest part of these floating pieces of Ice, as Bartholinus takes notice, are compiled of store of Snow fro∣zen together. Besides, it is observ'd, That most of those stupendious Mountains which lay so much above Water below rested on the Ground, so that probably they might have sunk much lower, had the Water been deep enough for them; for Mr. Hudson in his Voyage takes no∣tice, in a Bay that bears his Name, of a piece of Ice sevenscore Fathom deep.

7. Having said thus much of the expansion of Water, it perhaps may be expected, that I should say something of the expansion of aque∣ous Humours; and also of the degrees of the Condensation of Water and watry Humours: But as for the first, I doubt whether there be any expansion, except of the watry Parts of them; but if it may be of any use to

direct us in making an estimate of the diffe∣rent Proportions they contain of Phlegm, or o∣ther more spirituous Ingredients; I would not discourage those whose Curiosity shall prevail with them to prosecute such Experiments. And as for the condensation of Water by Cold, tho' perhaps in hotter Climates it may be considera∣ble, yet I have not found it very sensible in all the Tryals I have made here.

Particulars referrable to the X Title.

• 1. A Bolt-head whose Stem was 17 Inches above the Water being seal'd up, and placed about 9 hours in a frigorifick Mixture, the Water ascended 15 Inches ½ and afterwards ½ of ¼ of an Inch; being neglected for an hour the seal'd end was blown off, and the Bottom of the Glass broke in peices.
• 2. Water freed from Air in. our Receiver, and seal'd up in a round Bolt-head, in which the seal'd Apex was about 5 Inches above the Water, afforded an Ice very free from Bubbles, and having stood in a frigorifick Mixture about 2 hours, it was raised 4 Inches and ⅜: The Co∣nical Apex being broke with a noise and a seeming smoak, we found Water unfroze, un∣der the Pipe, and that the Air was condensed to a 20th Part of the space it possess'd before.
• 3. The Globous part of a Glass-Egg 3 Inches Diameter was filled with Water and froze from the Bottom upwards; after it had been Hermetically seal'd, it rose 8 ½ Inches, the length of the whole Stem being 10 Inches and a half. But being a second time sealed up and

• froze with Ice in it, it wrought not 4 Inches a∣bove its first station.

Notes

• * 1.1

  The expan∣sion and contraction of Liquors measur'd.