04 5" f 
* oob P 
26 Dr. Pearson's Experiments and Observations 
were very soluble in the mouth, and evaporated in white 
fumes, leaving a very slight black stain. 
15. Twenty grains of the precipitate were introduced into 
a tube, | of an inch wide in the bore, sealed by melting at one 
extremity ; which extremity was coated, and the tube was fitly 
bent for retaining sublimate, and collecting gaz. The tempe- 
rature, from the fire applied, was at first very low, but was 
gradually increased, so as to make the coated part, containing 
the charge, red hot. At first, the precipitate turned black, and 
a little water appeared. Secondly, gaz came over, which had 
the smell of empyreumatic liquor cornu cervi. Thirdly, a 
brown sublimate appeared, and gaz as before, but also with 
prussic acid gaz. Fourthly, black matter, staining the tube, as 
if from tar, or animal oil. On cooling, there was found a resi- 
due, of nearly three grains, of pure carbon. The sublimate 
was principally carbonate of ammoniac ; the rest was animal 
oil. The gaz discharged was nearly half its bulk, or 5 cubic 
inches by measure, carbonic acid ; and the remaining 5 cubic 
inches were nitrogen gaz, containing prussic acid and empy- 
reumatic oil. 
I treated in the same manner, the same quantity of reddish 
crystals, deposited spontaneously from urine. The result was 
not very different from that of the former experiment. The 
gaz was more offensive, smelling like putrid urine, and the 
carbonaceous residue was more copious, and contained lime 
and phosphoric acid; at least the lixivium of it became white, 
on dropping into it oxalic acid ; and it became slightly curdy, 
on adding lime water. 
I treated in the same manner, some quite round and smooth 
