244- -Dr. Pearson’s Experiments and Obfervations 
As it may be objected, that conclufions drawn concerning 
the nature of calces might be erroneous if nitrous acid had 
been applied previoufly to lubftances containing them, I made 
the following experiment. 
Experiment with marine acid applied to James’s Powder , which 
had not been expofed to the action of nitrous acid , or any other 
menjlruunu 
50 grains of James’s powder were digefted, and gently 
boiled in two ounce-meafures and a half of concentrated ma- 
rine acid diluted with one ounce of diftilled water till there 
remained only about one ounce- meafure. A great part of the 
powder appeared to be evidently diffolved. On cooling, cry- 
ftalsof muriated antimony were formed upon a white fediment. 
The clear liquid with the cryftals being decanted, the fedi- 
ment was boiled twice, as before, with marine acid ; but the 
fecond affufion of this menftruum brought off but eight grains 
of this powder, and the third only four grains. The remain- 
ing fediment, being well dried, weighed 14 grains. Now it 
has been fliewn already, that the nitrous and marine acids, fuc- 
ceflively applied, diffolved 444, or all but about 60 grains; 
and in the prefent experiment, the marine acid diffolved 44, 
which is in the proportion of 444, or nearly 444 ; fo that, on 
account of the trifling difference in thefe proportions, it may, 
perhaps, be fairly concluded, that the properties of the calx in 
James’s Powder are not altered by nitrous acid to affedl its 
iolubility in marine acid. And further, this infoluble powder 
in the prefent experiment was found to have the fame' proper- 
ties as that in the former experiments. 
To 
