[ 224 ] 



earth, 29,35 of real vitriolic acid, and S3i^S °f" water, it was 

 flandard acid that I had before mentioned, but its quantity of real 

 acid is as I now ftate it, as may be feen by calculation. 



Hence roo parts perfedly deficcated Epfom fhould contain 

 36,68 nearly of earth, and 63,32 nearly of real acid. 



And 100 grains mere magnefia take 172,64 real vitriolic acid, 

 and fliould afford 590 nearly of cryflallized Epfom. 



And 100 parts real vitriolic acid fhould take up 57,92 of mag- 

 nefia, and afford 340 nearly of cryflallized Epfom. 



According to Bergman 100 grains of magnefia take up 173 

 of real vitriolic acid. 



According to Wenzel 100 grains magnefia take up 181,8 real 

 acid, this arifes from his rating the mere earthy part of common 

 magnefia at 41,2 per cent, which, as I think, arifes from volatili- 

 zation of part of the magnefia. 



Experiment \Jl. Fourcroy, 2 An. Chy. 285,282. 



He found that cryflallized tartarin taken in the proportion of 

 80 parts to 100 of cryflallized Epfom operate an almoji total decom- 

 pofition of the Epfom. 



Application. 



