436 M. Stromeyer onPolyhalite. [Dec. 



acid obtained from 5-045 grra. of polyhalite is 2-6056 grin. If 

 we subtract, therefore, the quantity of sulphuric acid mixed with 

 thehmeand magnesia weighing 1-3043 grm. + 0-6677 grm. 

 = 1-972 grm. there remain 0-6336 grm. of this acid for potash, 

 which accordino- to the experiments of Marcet, indicate 

 l-4118grm. of sulphate of potash. 



From this investigation, it appears that from an analysis of 

 5-045 o-rm. of polyhalite, there are obtained 



Grammes. 



Anhydrous sulphate of hme (c?) 2-2410 



Anhydrous sulphate of magnesia {d and e) 1-0020 



Sulphate of potash (_/") 1-4118 



Red oxide of iron (6 and c) 0-0180 



4-6728 

 Consequently 100 parts of polyhalite contain 



Anhydrous sulphate of lime 44-4202 



Anhydrous sulphate of magnesia 19*8612 



Sulphate of potash 27-9841 



Red oxide of iron 0-3568 



92-6223 

 (C.) 



I afterwards submitted 6-573 grs. of this fossil to similar 

 experiments, but so as first of all to separate the lime of the 

 nitric solution from the magnesia by means of oxalate of potash, 

 then to precipitate the magnesia with carbonate of soda, and 

 afterwards unite each basis separately with sulphuric acid. By 

 which method are obtained 



Grammes. 



, Anhydrous sulphate of lime 2-5100 



Anhydrous sulphate of magnesia 1-1390 



Sulphate of potash * 1-5464 



Red oxide of iron 0-0200 



5-2154 

 Consequently 100 parts of polyhalite contain 



Anhydrous sulphate of lime 45*0386 



Anhydrous sulphate of magnesia 20-4378 



Sulphate of potash 27*7480 



Red oxide of iron 0-3588 



93*5832 



» There were obtained to wit8"568grm, of sulphate of barytes, or 2-913 of sul- 

 phuric acid, of which 2-219 grm. of sulphuric acid are to be reckoned for lime and 

 magnesia, and 0'694t grm. of sulphuric acid for potash. 



