MANUAL FOR SUGAR GROWERS. 67 



Eussia, Sweden, etc., large quantities of wood are 

 burned for tlie sake of the ash ; the potash is ex- 

 tracted from the crude ash by sokition in water, and 

 recovered by evaporation to dryness, the potash 

 being thus obtained as carbonate. Of late years ex- 

 tensive mineral beds of salts containing large quan- 

 tities of potash have been discovered in Germany, 

 and it is from this source that the potash used 

 for manurial purposes is chiefly obtained. One of 

 the most important of these minerals is kainit, a sub- 

 stance containing sulphates of potash and magnesia 

 together with common salt and other substances. 

 A good sample of kainit should contain twenty to 

 thirty per cent, of sulphate of potash ; from this 

 substance sulj)hate of potash in a comparatively 

 pure state can be extracted, and where, as in the case 

 of the West Indies, the manures have to be trans- 

 ported long distances, it is found more economical to 

 purchase the purified and concentrated form of sul- 

 phate, although the first cost is higher. Thus, with 

 freight at £2 per ton, if kainit containing twenty- 

 four per cent, of sulphate of potash were purchased, 

 the cost of the sulphate of potash would be increased 

 by <£8 per ton, while with purified sulphate of ninety- 

 six per cent, the increase in cost is only a little over 

 X2 per ton. This forms a very good illustration of 

 what has been said before, namely, that in the West 

 Indies it is economical to purchase manures in as con- 

 centrated a form as possible, and thus the use is de- 

 nied to the planters of many forms of manure which 

 in some countries are economical and useful. 



Another mineral containing potash, and which is 



