as On the Compofition and Properties 
- matter, ftaining the tube, as if from tar, or animal oil. On 
cooling, there was found a refidue, of nearly three grains, of 
pure carbon. The fublimate was principally carbonate of 
ammoniac; the reft was animal oil. The gaz difcharged 
was nearly half its bulk, or 5 cubic inches by meafure, 
carbonic acid; and the remaining 5 cubic inches were 
nitrogen gaz, containing pruflic acid and empyreumatic oil. 
I treated in the fame manner, the fame quantity of red- 
difh cryftals, depofited {pontaneoufly from urine. The re- 
fult was not very different from that of the former experi- 
ment. The gaz was more offenfive, fmelling like putrid 
urine, and thecarbonaceous refidue was more copious, and 
contained lime and phofphoric acid; at leaft the lixivium 
of it became white, on dropping into it oxalic acid; and it 
became flightly curdy, on adding lime water. 
I treated in the fame manner, fome quite round and 
fmooth concretions, of the fize of black pepper feeds. The 
products were the fame as the former, but the gaz was ftill 
more offenfive, and in fmaller quantity; and the carbona- 
ccous matter was more copious. 
I, in the fame way, fubjected to experiment 20 grains, of 
a nut-brown light calculus, which I had previoufly afcer- 
taincd to contain the matter above deferibed, which was 
precipitated from cauttic foda by acids. The produéts were 
of the fame kind as the former; but I could find no trace 
of phofphoric acid in the refidue, which I did of lime,” 
and the gaz was lefs offenfive. The carbonaceous refidue 
was not, in weight, 3 grains. 
It will be proper, before I proceed further, to point out 
fome of the more obvious conclufions from the above ex- 
periments. 
1. It appears that at leaft one half of the matter of the 
urinary cozicretions fubjeéted to the above experiments 
united to cauftic foda, and was precipitated from it by 
acids. (II. a—d.) 
3. This 
