New York Agricultural Experiment Station. 73 



purified and concentrated for market. The muriate of potash most 

 common in the market contains 80 to 85 per cent, of this product, 

 which is equivalent to 50 to 53 per cent, of actual potash. A still 

 more concentrated form, containing 95 to 98 per cent, of pure 

 muriate, is sometimes found in the market. 



Nitrate of Potash, commonly called saltpeter or nitre, is a most 

 valuable fertilizing material for potash and nitrogen also. The 

 demand for its use in the manufacture of gunpowder makes it too 

 expensive to use commonly as a fertilizer. It is found in the 

 market as " crude " nitrate of potash, containing about 44 per cent, 

 of actual potash, and also as " double refined " nitrate of potash, 

 containing about 46.5 per cent, of actual potash. 



Sulphate of Potash is a product of the German mines. Strictly 

 pure sulphate of potash contains about 54 per cent, of actual potash, 

 but the product found in the market is of variable composition and 

 purity. The highest grade form of commercial sulphate of potash is 

 90 to 95 per cent, pure and contains from 48 to 51 per cent, of actual 

 potash. Low-gra'de sulphates of potash contain as little as 30 per 

 cent, of actual potash, together with more or less sulphate of magnesia 

 and common salt. 



Sulphate of Potash and Magnesia is known also as double 

 manure salts or simply as double potash salts. This material comes 

 from the German mines, and contains 48 to 52 per cent, of sulphate 

 of potash, equivalent to 26 to 28 per cent, of actual potash. It also 

 contains 32 to 36 per cent, of sulphate of magnesia. 



Tobacco Stems contain from 6 to T per cent, of potash and 

 about 2 per cent, of nitrogen. They are ground fine and often used 

 in making commercial fertilizers. 



Wood-Ashes contain more or less potash, which is present chiefly 

 in the form of carbonate. The amount of potash in commercial 

 wood-ashes varies from below 4 to over 7 per cent., the average 

 being under 5 per cent. Wood-ashes also contain between 1 and 2 

 per cent, of phosphoric acid. The amount of potash in wood-ashes 

 depends upon a variety of conditions, such as the kind and age of 

 wood, the method of burning, and especially the way in which the 

 ashes are stored. Where ashes have been exposed to the weather 

 or leached, they contain much less potash, often only 1 or 2 per 

 cent. Ashes from lirne-kilns and brick-kilns are generally so mixed 

 with refuse matter as to possess little value for use as fertiHzers. 



