ees 
water were added, the fpecific gravity of the folution, temperature 
56°, was 1,0448, its weight was 949 grs. then - a of this 
weight was regenerated Epfom=92,494 grs. of falt; the quantity 
of mere earth was 35 X,45=15,75 grs. that of ftandard was 30,5, 
and the remainder= 53,75 muft have been water. 
Hence 1°—troo parts cryftallized Epfom contain 17 of earth, 
32,97 of ftandard acid; or in round numbers, 17 of earth, 33 
flandard acid and 50 of water. 
Hence 2%—10o parts pure magnefia take up 194 of vitriolic 
ftandard, and fhould afford 589 of cryftallized Epfom. 
Mr. Bergman found too parts Epfom to confift of 19 of earth, 
33 of the ftrongeft acid and 48 of water. Whence by him 100 
parts of this earth fhould take up 173,7 nearly of the ftrongeft 
acid, and produce 526 parts of cryftallized Epfom. 
Here the difference between our refults is apparently but 
fmall, refpeéting only the proportions of earth and water, he 
attributing two parts lefs both of earth and water, but though 
our expreffion relatively to the proportion of acid is the fame, 
yet our meaning is very different; for he means 33 parts of an 
acid of the fame ftrength as that found in tartar vitriolate, 
and I mean only ftandard vitriolic acid, which is much weaker, 
as 100 parts Epfom contain but 29 parts of an-acid of the fame 
concentration as that found in tartar vitriolate. This helps to 
explain a circumftance which appeared very fingular to Mr. 
Bergman : 
