ban 
Wira refpe@ to this laft the difference feems confiderable, 
but the reafon is that Mr. Cavendifh made the experiment from 
which he inferred the ftrength of this acid with vitriol of lead, 
though he expreffed it by reference to the quantity of marble he 
deemed it would diflolve. 
I atso tried to find the quantity of ftandard acid the dif- 
folved marble would require to precipitate it from its folutions 
in the muriatic and nitrous acids, and for this purpofe: To the 
folution of 158 grs. of marble in the marine acid above-men- 
tioned I gradually added after dilution oil of vitriol 1,5654. 
This operation is very tedious, as the vitriolic felenite is in great 
meafure foluble in the marine acid, or at leaft in the folution 
of marine felenite, fo that frequent evaporation and repeated 
wafhings were requifite; however it appeared to me that 253,5 
grs. of the acid were requifite to precipitate the whole of the 
diffolved calx. Now 253,5 grs. of this acid contain 154,33 of 
ftandard, confequently 1co grs. marble require for their preci- 
pitation from the muriatic acid 102 gfs. of ftandard vitriolic acid, 
or rather computing the marble to contain 52 per cent. lime, 
roo grs. pure calcareous earth require for their precipitation from 
the marine acid 124,15 of vitriolic ftandard. Perhaps the dif- 
ference between the quantity requifite in this cafe and that 
found requifite for folution may arife from this, that the argil- 
laceous earth remains untouched in this cafe, as no more acid 
is added when the decompofition ceafes to be vifible, whereas 
a fufficiency to diffolve and faturate it is added in the former 
cafe. 
To 
