A D I 



fluid, with a foctict odour, turning fyriip of violets green, 

 and manifclUy conialiiing ammonia in lolution ; ttic fo^ipy 

 matter remaining in tlie retort had acquircxl a greater con- 

 fiilence, was beeome Ida fuiible, of a deeper brown colour, 

 and iipon cooling, was evidently drier than before, though 

 not admitting of being broken. 



Two pounds of purified foapy matter were dillilled by a 

 very gradual fand heat ; after two hours, the matter was 

 nielted, and in ebullition, it foon became covered with a 

 blackidi fioth, and fwelled greatly ; dui-ing 36 hours nothing 

 came over but water witli ammonia in folution ; at length, 

 after 48 hours, ci-yftals of carbonated ammonia began to 

 line the adopter; thefe were foon after difTolved by a reddifli 

 brown oil, which continued to come over till the experiment 

 was ftopped. Hence it appears that the component parts of 

 this fubllance are water, ammonia, and a concrete oil. No 

 elaftic gas was difengaged during the whole proccfs. 



In order to afeertain the aftion of atmofphcric air on this 

 fubftance, feveral pieces being previoully weighed, were ex- 

 pofed to a v/rrm and diy air during a whole fummer ; they 

 were found by this to have becor.ie dry and brittle without 

 being lefTcned in their bulk, had acquired a whiter colour, 

 and loIL their peculiar odour ; their upper furface was be- 

 come friable, and almoft fell into po'Ader under the finger ; 

 on iubjeftioii to analyfis, it was found not only that the 

 water, but a confiderable part of the ammonia, had been 

 evaporated by this long expofure, and the remaining oily 

 matter on melting became femitranfparent, brittle, and con- 

 fiderably refembling wax. 



Some purified foapy matter was rubbed in a glafs mortar 

 with a little water ; an immediate mixture took place, and 

 the refult was a kind of magma, or foft unifonn pafte : by 

 a further addition of water an opaque liquor was produced ex- 

 aftly fimilar to a folution of foap ; like this, it formed a ftrong 

 lather, and by the addition of pump-water, acids, lime-wa- 

 ter, or metallic la'.ts, it curdled and threw up to the furface 

 a quantity of white infoluble clots. With nitrat of mercury 

 it gave a greyifh-yellow precipitate, and the fupernatant li- 

 quor became of a permanent red-purple. The aqueous fo- 

 lution being thrown on the filter depofited there almoft the 

 whole of the oily matter, and the clear liquor by evaporation 

 yielded a I'ttlc animal mucilage and extradl, and a fmall 

 variable proportion of the phofphats of ammonia and foda. 

 The combination with boiling water is not more permanent 

 than that with cold, the whole of the oil and ainmonia fe- 

 parating on the filter. When inftead of frefh foapy matter, 

 fome which had been expofed during the fummer to the ac- 

 tion of the air was made ufe of, the liquor, though of a 

 foapy appearance and feel, was much lefs fo than what was 

 made with the frefli fubllince, and upon boiling the mix- 

 ture a number of brown oily drops rofe to the furface, 

 which, on cooling, concreted to a femitranfparent matter 

 like wax, perfeftly analogous to that obtained from the 

 fame by fimple melting ; hence it appears, that the folubility 

 of the frefh foapy matter depends on the ammonia which it 

 contains, as is alfo evinced by the perfeftly clear folu- 

 tion which the addition of a further quantity of ammonia 

 occafions. 



Eight ounces of foapy matter, v.hite and purified, were 

 mixed with an equal weight of powdered quickliine, on the 

 addition of a little water, the mafs heated, fwclkd, and 

 difengaged a very ftrongly ammoniacal vapour, accompanied 

 by a peculiar putrefcent fmell ; a fufficiency of water being 

 then added to bring the whole to the ftate of an emulfion, 

 it was heated to ebullition, much ammoniacal vapour efcap- 

 ing at the fame time ; the liquor being thrown on a filter, 

 pafled perfeftly clear and colourlefs, and appeared to be 

 Vol. L 



A D I 



only lirrtc-water wiili n very fmall quantity of foap In fohi- 

 tion ; the matter remaining on the filter, being will wallitd, 

 was beaten up with water, but fhowcd no tendency to unite 

 with it, fubfiding after a time in the form of a white mafs 5 

 this by drying for a few days in the open air, becaire grey 

 and much reduced in volume : it was then mixed with di- 

 luted muriatic acid, which immediately dceompofed it j and 

 a number of white clots rofe to the furface of the liquor. 

 This lall being obtained clear by filtration, yielded tryftaU 

 of muriat of lime and a flight tiace of phofphoiic fait ; the 

 white clots being waflied and dried, and afterwards melted 

 in a water bath, cooled into a dry couibuftible oily matter, 

 brittle, waxy, cryllalli/.able, and perfeftly infoluble in water, 

 to which the name of adipucire has been appropriated. 

 From this feries of experiments with lime, it appears that 

 the foapy matter is a true ammoniacal foap, with a bafe of 

 adipocire to which lime has a llrongcr affinity than ammonia, 

 but which lall; compofition is agaui in its tum dceompofed 

 by all the acids, leaving the adipocire in a ftate of purity. 

 Pot-afh and foda produce cffefts perfeftly analogouo to thofc 

 of lime. 



The aftion of acids on this foapy matter is to decom- 

 pofe it, by uniting with the ammonia ; the concentrated 

 mineral acids, as the nitric and fulphuric, alfo deepen the 

 colour of the adipocire, by the evolution of part of its car- 

 bonaceous bafe. 



Pure alcohol at the ordinai-y atmofpheric temperature has 

 no aftion on the foapy matter, but when boiling, it will 

 with eafe diftblve one fourth of its weight, of which all the 

 ammoniacal foap will be depofited by cooling, and that por- 

 tion of adipocire which is uncoir.bined with ammonia* will 

 be held in permanent folution. Hence alcohol is perhaps 

 the beft agent that can be ufed in the decompofitlon of the 

 foapy matter : the phofphoric falts contained in it are not 

 foluble in alcohol ; the ammoniacal foap is wholly depofited 

 by cooling, and the uncombined adipocire may be obtained 

 afterwards by evaporating off the alcohol. 



The moft effeftual way of procuring perfeftly pure adi- 

 pocire, is to mix well the foapy matter with twelve times its 

 weight of warm water, and to decompofe it by adding a 

 flight excefs of acetic or muriatic acid. This concrete ani- 

 mal oil thus prepared, as long as it holds much water be- 

 tween its particles, is of a pure white ; by drjnng it acquires 

 a brownifii grey colour, which neither expofure to the air, 

 nor the oxymuriatic acid will remove : while it retrjns water 

 it is foft to the touch, and becomes duftile like wax by the 

 warmth of the hand : when well dried and deprived of wa- 

 ter, it aftlimes by flow congelation, a lamellar and cryftaU 

 line texture, but when cooled quickly, has a compadt gra- 

 nular appearance : in the firft of thefe ftates, it greatly re- 

 fembles fpern'.aceti, yet differs from it in the following parti- 

 culars. It requires a lefs heat for its fufion by ftven degrees 

 of Fahrenheit ; it is foluble in boiling alcohol in the pro- 

 portion of one ounce and a half, to one ounce of the fluid, 

 whereas the fame quantity of alcohol at the fame tempera- 

 ture, will fcarcely take up more than 36 grains of fperma- 

 ceti ; it fcpava;es alfo in cooling from this menftruuin, in a 

 much lefs decidedly cryftallir.e form than fpe- maceti does ; it 

 unites eagerly with hquid ammonia in the cold, which fper- 

 maceti does not in the fmalleft degree. 



To the foregoing experiments of Fourcroy, a few fafts 

 have fince been added by Dr. Gibbes. The receptacle at 

 Oxford for thofe bodies which have been ufed by the ana- 

 tomical profcfl"or there for his demonftrations, is a hole dug 

 in the ground to the depth of thirteen or fourteen feet, and 

 a little ilream is turned through it in order to remove all 

 offcniive fmell : the flefli contahied in this was found, on 

 G ^ examination, 



