Of the specific Gravities of Bodies.

i6t

Weight in spirits, they are above proof; if it lose;

Wore, they are under. For, the better thespirits are, they are the lighter; and the worse,the heavier. All bodies expand with heat andcontract with cold, but some more and some lessthan others. And therefore the specific gravitiesof bodies are not precisely the same in sum met? S in winter. It has been found, that a cubicln ch of good brandy is ten grains heavier in win-Wr than in summer; as much spirit of nitre, 20Stains; vinegar 6 grains, and spring-water 3.wence it is most profitable to buy spirits in^wtei-, and fell them in summer, since they are«ways bought and fold by measure. It hasocen found, that 32 gallons of spirits in winterWill make 33 in summer.

The expansion of all fluids is proportionableW the degree of heat; that is, with a double orbiple heat a fluid will expand two or three times28 much.

Upon these principles depends the construe- The tkr-bon of the thermometer, in which the globe or*wib, and part of the tube, are-filled with afluid, which, when joined to the barometer, ispirits of wine tinged, that it may be more easilyeen in the tube. But when thermometers areWade by themselves, quicksilver is generally

used.

In the thermometer, a scale is fitted to theu °e, to (hew the expansion of the quicksilver,a nd consequently the degree of heat. And, as\fihrenheit\ s ca i e is most in esteem at prelent, IJail explain the construction and graduation of^ometers according to that scale,j , wst. Let the globe or bulb, and part of thebilk’-* 36 Abed with a fluid; then immerse the1 b in water just freezing, or snow just thaw-ing s

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