96 Fertilizers 



the excess of both the chlorids of sodium and magnesium, 

 which are injurious to the tender rootlets. Where its use 

 is intended to benefit the immediate crop, it should be 

 applied a considerable time before the crop is planted, in 

 order that it may be well distributed, and that a portion 

 of the chlorids, which are extremely soluble, may be washed 

 into the lower layers, or into the drains. 



Hardsalt. 



This is another crude potash salt which is imported for 

 fertilizer purposes. Its composition is very much like 

 kainit except that it contains more water in combination. 

 It is a mixture of chlorid of potassium, sulfate of mag- 

 nesium and chlorid of sodium. The commercial product 

 sold in the United States is guaranteed to contain 16 per 

 cent of actual potash. Its use as a fertilizer is the same as 

 that of kainit. 



Carnallit. 



Carnallit is of practical importance as a fertilizer only 

 in localities not far distant from the mines and is men- 

 tioned because it is the chief source of muriate of potash 

 and other concentrated potash salts. It is really a double 

 compound of muriate of potash and magnesium chlorid 

 and has associated with it large quantities of common 

 rock salt and kieserit, which is sulfate of magnesia, and 

 other minerals. It contains about 9 per cent of actual 

 potash and has the property of absorbing large quantities 

 of water. 



Muriate of potash. 



Of the more concentrated potash salts, muriate of potash 

 manufactured from carnallit is by far the most common 



