MODERN HIGH FARMING. 59 



after the purification of gas. These liquors are mixed with fresh 

 slacked lime and forced to the top of small towers, into which are 

 fitted a series of trays. The liquid flowing over the edges of these 

 trays in a succession of small cataracts, is met and traversed by a 

 column of steam, which during its ascension, deprives it of all its 

 ammonia. 



The steam thus charged is conducted to a coil of perforated 

 pipes in a tank of sulphuric acid, to which, as it passes through, the 

 ammonia is yielded up. 



When the acid is fully saturated, it is led into another tank and 

 allowed to settle, and finally is subjected to a process of hot concen- 

 tration to effect the crystallization of the sulphate of ammonia. 

 This salt has the form of white or greyish transparent crystals, is 

 sharp and bitter to the taste, is soluble in twice its weight of cold 

 water, and contains an average of twenty-one per cent, of nitrogen. 



We have before alluded to it as an invaluable source of nitrogen, 

 and this, although sufficient, is not the only virtue for which it recom- 

 mends itself. 



Our own experiments induce us to believe that when introduced 

 into the soil, the sulphuric acid set free by its natural transformation, 

 largely assists the decomposition of all surrounding organic remains, 

 and transforms any phosphoric acid that may be present into acid 

 or soluble phosphate. 



NITRATE OF SODA is a natural mineral, principally found in 

 Chili and Peru, and shipped from Iquique. It occurs in large beds, 

 several feet thick, intimately mixed up with sulphate, chloride, 

 iodide of sodium and many other bodies, and when in this state is 

 known in commerce as caliche, or crude nitre, of which the follow- 

 ing is a typical analysis : 



Nitrate of Sodium 63.92 



Sulphate " 4.01 



Sulphate of Lime Traces. 



Sulphate of Magnesia Traces. 



Chloride of Sodium 28.32 



Iodide " 76 



Insoluble Matter. . . 2.99 



100.00 



