4-0 The Complete Englífh e Difpenfatory. Part L

tion, that the Proportion of thelpe- Waters, the Gravity of all which is

cific Gravity of Wate r ro that of Air,is fomething more than 800 to 1.Since therefore fimilar Spheres or So-lids, are to one another as the Cubesof their Diameters, and the fpecificGravity decreafes reciprocally, in thevery fame proportion as the Cubes oftheir Diameters increalè; in orderto make a Particle of Water lighterthan a Particle of Air, no more isneceiîâry, than to rarity it till its Di-ameter becomes ten times greater,■which in this café is but a very fmalldegree of Rarifatlion ; for the Cubeof the Diameter, in a Particle ib ra-rify'd, is 1000. If the Diameter be

proportionably lefs, and theix-Rarwfaction more eafy, thanof commonWater, are drawn off proportiona-bly fooner by the Ret ort. On the o-ther hand, acid Spirits, fuch as theSpirit of Salt, of nitre, and of Vi-triol, tho they begin at firif. to rilemore read ily, yet require longer timeto carry them into the Receiver, thanWater it felf does: For tho theRarifaclion of Water be lefs, yet'tis not fufticient to anfwer to theGraiity of thofe Fluids. After thefame manner the Particles of Vege-tables and Animals, whofe Textureis rarer, and confèquently makes

made eleven times greater, the Cube them fpecifically lighter, more eafi-will be 1331,- and if twelve, 172S. lyafcend, than the Particles of Mi*

So that Water, when rariiy'd buttwelve degrees, will be above twicelighter than Air. And if the Rar i-faäien be carried on farther, it mayeafily be collected f.om the Increaieof the Numbers, that a Particle ofWater may be made almoff. infi-nitely lighter than Air. And thatthis may be brought a little nearerto the prefentpurpofe, 'tis m an i tell,that the Elevation of Bodies, equal-ly fluid and heavy, is always propor-tionable to their different Aptitudeto be rarify'd; that is, they afcend«juickerupon the Application of any

nerals or Metals. We may herealio obferve, that a Body, when dif-till'd, is always thinner and morefubtlc than the crude one, fromwhich it was diflill'd: So Rofe-Wa-ter has a lefs Confidence than theJuice of Rofes, and is lefs ponde-rous; and thus rectify'd Spirits havea lefs fpecific Gravity, than thofewhich have but once pafs'd the Fire.But the calé is other wife, whenAbflraBion is ufed in Diftilling j forinifance, diflill'd Vinegar is heavierthan crude : for in this Operation,a Liquor is left behind faturated with

Force, the more fufecptibie they are faline Panicles, whilfl ail ihcphleg*of Rarifaciion: but in Bodies, whole math Part, whofe Gravity is lefs,

Aptitude to be rarify'd is equal, thetime of Alcent is to be determin'dby their fpecific Gravity. So thatthe time of Elevation of Bodies, dif-till'd after this manner, is in a com-pound Proportion of the Rarifac-tion and fpecific Gravity. This ex-actly agrees not only to Theory, butto Experience,without which.Theo-ry alone is not to be regai ded : for

is carried oft. The fame thing isconftantly obferv'd in the Dephieg-tnation ai acid Spirits. ■

Not only fpecific Levity fervesto elevate Bodies in Diftillation, buta external Imfulfe alio may cauiêtheir Afcent. The Impulfe whichwe have to do with in this place,comes from the Fire, whofe Parti-cles, tho they are extremely fmall

by the fame degree of Heat, Spirit and light, yet 'tis demonftrable by&f Wine, Spirit of Sal Armoniac pre- Mechanics, that they may railé Bo-par'd with 3ukk-Lime, and DißilL'd dies much heavier than themfelves,

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