71 BOARD OP AGRICULTURE. [Jan., 



salt was, it was yet the least valuable of the treasures which were 

 hidden below. 



On this layer of salt there rested enormous beds of saline com- 

 pounds known to contain a great deal of magnesia and some pot- 

 ash. To get at the salt below, these magnesia and potash salts 

 had to be dug out and dumped on waste land at the mouth of the 

 mine. 



In 1860, the chemist Rose called Bittention to the waste, and the 

 government encouraged fertilizing experiments with a view of 

 utilizing this material, and also offered premiums to manufacturers 

 who should devise methods of producing high-grade potash salts 

 from them. In both directions there was complete success. 



The economical manufacture of potash salts was accomplished ; 

 and the farmers, who were discouraged at first on account of the 

 uncertain composition of the material supplied for experiment and. 

 the evil effects in many cases of the large quantities of chloride of 

 magnesia which the crude stuff contained, found in the manufac- 

 tured articles of standard composition an invaluable addition to 

 their supply of fertilizers, and an addition most thoroughly appre- 

 ciated in a land where the potato and sugar-beet crops fill such an 

 important place.* 



I have no time to speak of the various compounds in which the 

 potash occurs there, nor of the somewhat complicated processes of 

 preparation. 



None of the potash which reaches the market, or only a very 

 insignificant amount, is in the form in which it was mined. The 

 salts from the mine are purified by solution, decantation from less 

 soluble materials, and re-crystallization; the object being to make 

 them a3 concentrated as possible, and to remove as completely as 

 may be chloride of magnesium, which, even in small quantities, 

 may seriously damage a crop. 



In considering guano we have seen how, by the agency of birds, 

 vast stores of fertilizing material have been recovered from the 

 sea and stored in a safe, dry place for our use. The Stassfurt 

 mines bring to light a whole inland sea evaporated to dryness, 

 leaving its saline matters deposited in regular succession, stratum 



•From 1863 to 1865 the price of chloride of potaeBium declined more than 50 per cent., 

 and many of the factories were niined. But more economical method? were at once in- 

 troduced, and tlioiii,'h the price has declined since, the business is a very remunerative 

 one. It i-" believed that the price could be slill further reduced, and yet leave a very good 

 margin for manufacturers. 



