Dr. Pearfon’s Experiments on Calculi. 265 
atid for my leGtures. Nor, is it accurate to fay, that the 
acid fublimate obtained by Scheele by treating the urinary 
calculi by fire, was taken for the fame as the precipitate of 
their folution in fixed alkali by an acid; fince the French 
chemifts, in announcing that a portion of the lithic acid 
was fublimated without decompofition, 'propofed the procefs 
of fublimation to obtain the lithic acid; and fince I have 
particularly deferibed the decompofition of the greater part 
of this acid by fire, when I announced its property of being 
convertible into the Pruffic acid. But I {hall now proceed to 
detail the experiments, as I fhall have occafion fevera! times 
to fhew that Dr. Pearfon has been fingularly mifled in re- 
gard to our lithic acid. 
[Cit. Fourcroy then gives a pretty full account of Dr, 
Pearfon’s experiments, which it would be ufelefs to repeat 
here, as we have already in the laft two numbers of the pre- 
fent work laid the paper at full length before our readers. 
On'Dr. Pearfon’s expreffion (Phil, Mag. vol. ii. p. 130), “ I 
*€ fhall next relate fome experiments made in order to ob- 
* tain the acid fublimate of Scheele, or lithic acid of the 
* riew fyftem of chemiftry,”’ the French chemift makes the 
following remark: “ I muft obferve that thefe words prove 
that Dr. Pearfon did not underftand very clearly the refults 
of Scheele and of the French chemifts; for ncither the on 
nor the other have ever confidered as real lithic acid the 
produét fublimated by fire from the urinary calculus, but 
only the matter of the whole calculus precipitated in cryttals 
from the boiling waver with which it has been treated, or frony 
its folution in fixed cauftic alkali by an acid. J muft remark 
here alfo, that Schecle in his differtation has accurately dils 
tinguifhed this fublimated portion from the real acid of the 
urinary calculus not treated by fire ; that he has compared 
it to the volatile acid falt of amber; and that Cit. Vauque- 
lin, in an article which he furnifhed’ for Defchamp’s Traité 
dé la Lithotomic, vol. i. p. 132, &c. took great care to point 
put that the fublimated produce of the calculus of the blad- 
y der 
