C A C
CAL
( m )
than that of the atmofphere to preferve them ina fluid ftate have obtained the name of vegetablebutters. Of thefe die beft known to Europeansis the Palm Oil , procured from the fruit of theCocos butyracea. The common Cocoa-nut alfo,and the Chocolate-nut, may be made by preffureto yield a fimilar concrete oil. Mr. Park, in histravels in Africa , defcribes another tree, calledby the natives Shea, from the fruit of which a
very pure butter is alfo obtained. See OilsVegetable exprefeJ.
BUTTON. Korn, Germ. Bouton t Fr.
The rounded mafs of metal which is colleftedat the bottom of a crucible after fufion, or whichremains in the cupel after cupellation, is calledby this name. If the button is folid, flightlyconvex and fmooth on its upper furface, it is afign of the procefs of reduction or cupellationhaving been well performed.
c
CALAMINE. See Zinc.
CALCAREOUS SPAR. See Limestone .
CALCINATION. Calcination , Fr. CalcinirenVerhalchen, Germ.
CALX. Chaux, Fr. Kalch, Germ.
The term calcination is derived from the iatincalx, which fignifies quick-lime, and is appliedby the old chemifts to the converfion of a com-paratively denfe fubltance into a light and porousone, by the a£tion of fire. The diminifhedfpecific gravity of bodies that have undergonecalcination was fuppofed in all cafes to provethe volatilization of one or more of their con-ftituent parts, and as this was in many inftancesaccompanied by combuftion, the two termscame in fome meafure to be confounded. Hencein the writings of Glauber, Kunkel, and evenBergman, we find ujh/s ufed almoft fynonimouflywith calcinatus . There is however this diftinc-tion to be noticed between them, that ujlusrefers fimply to the procefs, while calcinatusrefpects alfo the refult of the procefs. Thusuftion may be performed repeatedly on the famefubftance, producing more or lefs change in it■each time, but calcination when once broughtabout is perfect, and a pure calx is liable, byany fubfequent expofure to heat, only to bevitrefied. For example : if a bone is placed inan open fire, the oil foon begins to exude andburns with a bright flame; when this ceafes therefidue is, properly fpeaking, burnt bone, andconfifts of earthy matter penetrated by charcoal •,by a fecond expofure to fire the burnt bonelofes its charcoal, and nothing remains but thewhite earth; it is now in the ftate of calcinedbone or bone-alh, becaufe it is incapable of anyfurther decompofition by Ample heat. A calxtherefore is to a fubftance burnt in an open fire,what a caput mortuum is to a fubftance that hasbeen diftilled; they are each the ultimate refults
VOL. i.
of the action of heat in open and in clofe vef-feis. Moft metals when expofed to the jointaction of heat and air are converted to a loofepowdery fubftance which was denominated bythe old chemifts the calx of the metal, butwhich in the modern nomenclature is called anoxyd: and becaufe the action of acids, efpeciallythe nitric, has a fimilar effect on fome of themetals to that which is produced by fire, theterm calcination when applied to thefe bodiesindicated the converfion of them into calceseither in the moift or dry way. But though theold term, as applied to metals, is fuperfeded byoxidation, yet it may ftill very conveniently beretained to exprefs the feparation of the fixedfrom the volatile parts of bodies by means of anaked fire. In which fenfe we fay calcinedbones, calcined flints, calcined potafh, calcinedclay, &c.
CALCINED MERCURY. Mercurius cal-cinatus. A common pharmaceutical name forthe fimple red oxyd of mercury. Sec Mercurycxyds of.
CALCULUS biliary SeeBiLi ary Calculus.CALCULUS urinary. See Urine.CALOMEL . See Mercury.
CALORIC or Heat. Calorique, Fr. War-mejlqff\ Germ.
The nature and properties of heat afford amoft extenfive and interelling fubje£t for phr-lofophical enquiry, which has been purfued withfo much ardour and fuccefs that it would occupya volume barely to enumerate all the refearchesto which it has given rife for the courfe of morethan a century in many countries of Europe .We muft therefore content ourfelves with feledf-ing the refults of a few Only, and particularlyof thofe of later date, together with a generalview of the prefent ftate of knowledge on thisftibjecl, which the experience of every yearfhews to be ftill imperfect, and ftill to pvomii'ea rich harveft of difeovery for future enquirers.z