372 



BOAED OF AGRICULTURE. 



this mineral usually is offered for agricultural purposes. One 

 consists of the selected pieces of the crude mineral, merely 

 crushed to a coarse powder; it forms, therefore, a more or 

 less wet mass of a bluish gray color. The other is of a 

 yellowish gray color, and consists of the slightly calcined and 

 subsequently coarsely pulverized crude mineral. The follow- 

 ing analyses illustrate well their respective composition and 

 value : — 



I. 



Crude Kieserite. 



Sulphate of magnesia, ...... 54.56 



Sulphate of lime, 9.23 



Chloride of magnesium ...... 2.12 



Insoluble matter (sand, etc.), . . ». . . 3.00 



Water, 31.09 



100.00 

 II. 



Calcined Native Sulphate of IMagnesia. 



Sulphate of magnesia, ...... 75.94 



Sulphate of lime, ....... 2.80 



Insoluble matter (sand, etc.), ..... 1.52 



Water, 19.74 



No. I. has been oflfered for sale in Baltimore at from $11 

 to $12 per ton; No. II. is offered at Stnssfurt at $10.80 

 (gold), in cases of less than five tons. The comparative 

 cheapness of this magnesia compound has caused of late care- 

 ful inquiry on the part of German agricultural chemists 

 regarding its agricultural value. The results obtained leave 

 no doubt about its merits. As sulphuric acid and magnesia 

 are known to be essential for the groAvth of plants, a (arti- 

 ficial) direct supply to the soil must be considered very 

 judicious, wherever large quantities of both have been re- 

 moved from the soil by the crops raised upon it. 



Sulphate of magnesia aids also in a superior degree in the 

 distribution of the potassa throughout the entire body of the 

 soil, down to the subsoil ; it exceeds greatly the gypsum as 

 an absorber of ammonia. To sprinkle daily a few pounds of 

 it over the fresh stable-manure, suffices to secure all the 



