ARTIFICIAL AND CONCENTRATED MANURES. 97 



largely used directly upon the land. It is composed of 

 a number of salts, chiefly "sodium chloride/' or ordi- 

 nary salt, '^ magnesium chloride," " magnesium sulphate," 

 and "potassium sulphate." 



Although the potash in kainit is in the form of a 

 sulphate, its effect is quite similar to that derived from 

 the use of muriate, because of the large quantities of 

 chlorides contained in it, in combination with magnesia 

 and soda. It is not rich in potash, containing on the 

 average twelve and one-half per cent of actual potash, 

 or potassium oxide. 



Sylvinit. — This is a crude salt, similar to kainit in 

 that it contains relatively small amounts of actual pot- 

 ash, though the potash in sylvinit exists both in the 

 form of a sulphate and of a muriate, or chloride. There 

 is, too, in this salt less of the magnesia compounds than 

 in the kainit. Sylvinit is not largely exported to this 

 country. The analyses of the products used here show 

 an average of sixteen per cent actual potash. 



Kainit and Sylvinit as Indirect Manures. — These 

 crude salts are valuable as indirect manures in that the 

 salts present, other than the potash, have a solvent effect 

 upon other soil constituents, particularly phosphates ; 

 they also aid in many cases in improving the physical 

 character of soils. It is believed, too, that the magnesia 

 contained in them serves as direct food under certain 

 circumstances, though this point is not regarded as of 

 great importance. 



The Application of Crude Potash Salts. — In the 

 use of these forms of potash, it is recommended that 

 their application should precede by a considerable time 



