VARIATIONS IN COMPOSITION. 



371 



II. 



(a) 



II. 



(b.) 



Chloride of potassium, 

 Sulpiiate of potassa. 

 Chloride of mao;nesium, 

 Chloride of sodium, 

 Sulphate of lime, . 

 Sulphate of magnesia, . 

 Insolubles, . 

 Moisture, 



19. 

 14.2 



42. 



13.6 



4.8 

 6.4 



30.9 

 11.7 

 8.6 

 32. 



8. 



1.6 



6.8 



43.5 

 10. 



6.7 

 26. 

 .6 



7. 



1.4 



4.8 



28.5 

 15.6 

 28.6 



2.9 

 17.6 



2. 



5! 



80. 



04 gold. 



21 60 " 

 31 20 " 

 15 12 " 



Price per ton of 2,000 pounds. 



No. 1 contains from 9-11 per cent, of potas- 

 sium oxide, ...... 



No. 2 (a) contains 25 per cent, of potassium 

 oxide, ....... 



No. 2 (b) contains 30 per cent, of potassium 

 oxide, ....... 



No. 3 contains from 15-18 per cent, of potas- 

 sium oxide, ...... 



No. 4 contains 43 per cent, of potassium oxide, 65 52 " 



No. 5 " 50 " " " 40 32 " 



No. 6 " from 28-30 per cent, of potas- 

 sium oxide, . . . . . . 51 82 " 



These prices apply to quantities less than tive tons ; above 

 that amount reductions are considerable. The value of the 

 potash varies per pound, as may be noticed from the previous 

 statement, from 4.5 cents to 7.6 cents. It is more. expensive 

 in the form of a sulphate than in that of a chloride. In regard 

 to further details concerning the most approved modes of 

 their application for special purposes, I refer to a previous 

 communication published in the tenth annual report of the 

 trustees of the Massachusetts Agricultural College. 



Native Sulphate of Magnesia (Kieserite). 

 This compound occurs in large quantities in the salt mines 

 at Stassfurt, Germany, either in isolated layers or associated 

 more or less with the various constituents of the previ- 

 ously described " potash salts." There are two forms in which 



