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volatile had diftilled over. On opening thereceiver when cold, a moft pungent fuffocatingfetid vapour exhaled, which is charafteriftic ofthis procefs, and the receiver contained threefubftances, namely, a congealed oil of theconfiltence of hog’s lard, and ftrongly pungent,over which fwam two liquors perfectly diftinct,the upper of which was a greenilh limpid oil,and the lower was a molt pungent gold colouredacid liquor. I he retort contained about i \ oz.of a fmooth glofiy charcoal. The congealedoil ftill retained much of the acid liquor, whichwas feparated by melting and walhing with hotwater. This walhed oil was fubjeCted tofeparate diftillation, by which it was againrel'olved into a congealable oil, and an acidliquor, and the fame procefs was repeatedfucceffively with each produd of congealed oilafter walhing, till all the acid liquor which itwould yield was got out. By a fucceffion of dif-tillations of the congealed refidue, the quan-tity of it gradually diminilhed, and at laft itfinally difappeared; fo that the whole 2 lbs. offuet was refolved into various liquid produds,and a carbonaceous refidue. The former wereall mixed together, and then fpontaneoullyfeparated into two liquors, one a golden colour-ed acid, weighing 3 oz. 5 drams, the other ayellowilh brown oil, weighing 21 § oz. Thecharcoal weighed 5 oz. 2 l'cruples, whichweights added together left a deficiency fromthe original quantity of fuet, amounting toj oz. 6 drs. t fcr.

We fhall not follow this laborious chemift inhis experiments on the oil and the charcoal,except to mention that the former after walhingto feparate the adhering acid, yielded by diftil-latian in a very gentle heat with water, a limpidoil refembling that of Dippel, already mentionedunder the article Bane.

The acid liquor which was brown, was thendiftilled per je in a gentle heat, by which ayellowilh white and rectified acid liquor wasobtained, and a carbonaceous greafymafsremain-ed in the retort. This rectified liquor was thencombined with the feveral alkaline, earthy, andmetallic bafes, with many of which it unitedvery readily, effervefeing ftrongly with theircarbonats and producing neutral falts, fome ofwhich will be prefently deferibed.

The fame ingenious chemift fucceeded in con-centrating this acid by faturating the acid liquorwith potalh, evaporating and thoroughly dryingthe fait, and then decompofing it by the ful-p'nuric acid and diftillation, by which a ftronglimpid acid was obtained.

But as this method was attended with muchtrouble and wafte, the following mode wasemployed as an improvement in the procefs:a ley of cauftic potalh was made with a poundof fait of tartar, and half a pound of quicklime,which was difl'olved in 6 lbs. of water. Afourth part of this was boiled with a pound offuet, and the whole evaporated till it began toftiffen confiderably. The remaining three fourthsof the ley were then added, and the whole wasboiled with a flow fire and conftant ftirring, tillthe mixture became pellucid, and when coldconcreted into a kind of gelatinous foap. This-was then difl'olved in water and fome powderedalum was added, which immediately produceda decompofition, the oil of the foap uniting folelywith the alumine into an infoluble curdy mafs.The addition of alum was continued till the form-ation of this curdy mafs had ceafed, and the li-quor feparated from it now contained fulphat ofpotafh, and another neutral fait of potalh, and theacid of fat. This was evaporated to drynefs andthen put into a retort, to which was addeda third of its weight of oil of vitriol, whichimmediately extricated grey vapours ftronglyimpregnated with the peculiar fmell of the acidof fat. By applying a very moderate heat, allthe acid of fat was expelled, unmixed with,fulphuric acid, and it condenfed into a fuming,limpid, ftrong acid of fat, which when added toa folution of acetited lead produced a precipitate:which was again folubla in an excefs of acetousacid, and therefore contained no fulphuric acid.

When this limpid acid of fat was diftilled ina retort till half the quantity had come overclear and colourlefs, the refidue now acquireda golden colour, and depofited brown ftreaks.The limpid acid in the receiver, again diftilledper fe, again refolved itfelf into another limpidfluid which pafled over into the receiver, andthe refidue as before depofited thefe brownftreaks. This was repeated eight times, alwaysfeleCting the clear liquid which had been diftilledover in the previous operation, and, to the laft,a quantity of brown infoluble matter was leftbehind, whilft the diftilled acid gradually loftits pungency, and fomewhat of its acidity, bythefe fucceflive procefles.

There are at leaft three ways of obtaining thisvolatile acid of fat; one is by mere diftillation ofany animal fat, feparation of the acid liquorfrom the other produffs, and rectification inthe way already mentioned, and in this way nointermede whatever is employed. Another wayis by decompofing an animal alkaline foap byalum, and diftilling the clear remaining refidue