[gag 
To obtain ftill more fatisfaGion I alfo precipitated the nitrous 
folution of marble above mentioned by a folution of tartar 
vitriolate. This folution contained 135 grs. of marble; the 
quantity of tartar vitriolate neceflary to precipitate it was 174 grs. 
Now 135 grs. marble contain 70,2 of pure calcareous earth, and 
174 g1s. tartar vitriolate contain 87 ftandard vitriolic acid ; whence 
it follows, that if 70,2 require 87, 100 will require 123,93 
nearly, the fame as when the uncombined acid was ufed; this 
experiment is therefore a proof of the accuracy of fome of the 
former determinations. 
Tue felenite thus obtained being fo far dried as to retain its 
filky glofs, weighed 205,25 grs.; hence 100 parts of it fhould 
contain 34 of earth, 43 of ftandard acid, and 23 of water. 
This determination, which varies confiderably from the former, 
appears to be more exact, becaufe in diffolving marble part of 
the acid is neceffarily taken up by the argillaceous earth con- 
tained in it, whereas here nothing is brought into the account 
but the acid taken up by the earth precipitated, that is, by the 
calcareous earth fingly. The proportion of water is alfo dif- 
ferent, becaufe the deficcation was not pufhed fo far. 
Accorpine to Mr. Bergman, 100 parts gypfum contain 32 
of earth, 46 of acid and 22 of water. If he means acid of the 
fame ftrength as that contained in tartar vitriolate, (which he 
muft mean, or the expreffion is ambiguous) he is certainly 
miftaken, for then 115 parts tartar vitriolate fhould contain the 
fame quantity of acid as 100 parts gypfum, whereas by the laft 
experiment 
