356 BOARD OF AGRICULTURE. 



The difference in the composition of samples 1 and 2 is 

 mainly due to their different state of moisture. Both are 

 fair specimens of their kind. The low percentage of nitrogen 

 in sample 3 is caused by an exceptionally large admixture of 

 soil. Wherever the entire deposit shows a similar amount 

 of earth}- admixture, a direct cultivation, after draining, 

 suggests itself as worth trying. 



Crude Kicserit, 

 (Crude Sulphate of Magnesia. Of Bowker Fertilizer Co., Boston, Mass.) 



Per cent. 



Moisture, at 100° C 31.90 



Calcium oxide, 2.60 



Magnesium oxide, 13.50 



Sulphuric acid, 29.10 



Insoluble matter, 5.00 



Magnesium in form of chloride, 0.60 



Magnesium in form of sulphate, 38.70 



Valuation per two thousand pounds, from $8 to $10. 



The "Kieserit" occurs among the salines of the salt mines 

 at Stassfurt in Germany, which of late have acquired a par- 

 ticular importance as leading resources of potash compounds 

 for agricultural purposes. Although it forms distinct layers 

 of considerable thickness, it is quite frequently found more 

 or less saturated with a solution of magnesium chloride when 

 removed from the mines. Well-established experimental ob- 

 servations regarding the injurious influences of the latter 

 compound on the healthy growth of roots render its pres- 

 ence objectionable, and consequently its removal, as far as 

 practicable, desirable, whenever kieserit shall be used for 

 agricultural purposes. 



The removal of any objectionable percentage of magne- 

 sium chloride is usually accomplished by subjecting the 

 crude material to a moderate calcination. The moisture 

 present largely decomposes, at a high temperature, the mag- 

 nesium chloride into hydrochloric acid, which escapes, and 

 into magnesium oxide, which remains behind. We find, for 

 this reason, the calcined and uncalcined kieserit in our 

 markets. The former contains, for obvious reasons, a larger 

 percentage of magnesia than the latter ; yet it is usually less 

 soluble in water. Both kinds ought to be well ground to 

 render a proper distribution possible. 



