283

Hydrostatics.

ciple. By it we have a mojl useful and readyMethod of finding the various comparative orspecific Gravities of Fluids atid solid Bodies,

to

Sea-Water , Salt-Spring-THater , &c. And on the otherSide you mark the Division to which it sinks in va-rious lighter Fluids, as Hot- Bath-Wat er, BriJiol-JVa-ter , Lincomb-Water, Cheltenham-Water , Port-Wine yMountain , Madeira , and various other Sorts of Wine.But in this Cafe, the Weight F on the Top must be alittle less than before, when it was used for the heavierWaters.

7. But in Cafe of trying the Strength of spirituousLiquors, a common cylindric Stem will do best, be-cause of its Strength and Steadiness ; and this ought tobe so contrived, that when immersed in what is calledProof-Spirit, the Surface of the Spirit may be upon themiddle Point G, which is easily done by duly adjust-ing the small Weight F on the Top, and making theStem of such a Length, that when immersed in Wa-ter, it may just cover the Ball, or rise to A ; but whenimmersed in pure Spirit, it may rise to the Top at F ;then by dividing the upper and lower Parts GA, GF,into ten equal Parts each, when the Instrument is im-mersed into any Sort of spirituous Liquor, it will imme-diately strew how much it is above or below Proof.

8. This Proof Spirit consists of half Water, and halfAlcohol, or pure Spirit, that is, such as when pouredupon Gun-powder, and set on Fire, will burn allaway, and permit the Powder to take Fire, which itwill, and flash as in the open Air. But if the Spirit benot so highly rectified, there will remain some Phlegmor Water, which will make the Powder wet, and unfitto take Fire. This Proof Spirit of any Kind weighsseven Pounds twelve Ounces per Gallon.

g. The common Method of shaking the Spirits in aVial, and by raising a Crown of Bubbles, to judge bythe Manner of their rising and breaking away, whetherthe Spirit be Proof or near it, is very precarious, and ca-pable of great Fallacy. There is no way so easy, quick,certain, and philosophical, as this by the Hydrometer ,which will demonstrate infallibly the Difference of

Bulks,