SULPHATE OF AMMONIA. 147 



1896. 1897. 1898. 1899. 



Tons. Tons. Tons. Tons. 



From gas works ...127,498 132,724 129,590 133,000 



ironworks ... 16,511 17,779 17,935 18,700 



,, shale works ... 37,822 37,153 37,264 37,300 

 ,, "producer," coke, 



and carbonising works 9,078 10,624 11,568 13,000 



Total ... ... 190,909 198,280 196,357 202,000* 



Of the 202,000 tons produced in 1899, 140,370 tons were 

 exported. In 1900 the total production was estimated at 

 213,000 tons, in 1901 at 220,000 tons. 



The average price of sulphate of ammonia during 1899 is 

 given as 11 5s. 9|d. per ton, as against 9 9s. 7^d. in 1898 

 and 7 18s. 4|d. in 1897.1 Its present price (March, 1902) 

 is about 11 11s. Od. 



Numerous experiments on the relative advantages of nitrate 

 of soda and sulphate of ammonia as sources of nitrogen have 

 been made. The general results may be summarised thus : 



1. Nitrate of soda is quicker in its action, being already 

 capable of yielding its nitrogen to the crop. Sulphate 

 of ammonia must first undergo nitrification in the soil 

 before it can be utilised to any extent by the plant. 

 For this process to occur it is necessary that some basic 

 material (generally calcium carbonate) be present in 

 order to (1) combine w r ith the sulphuric acid of the 

 sulphate (the calcium sulphate formed is carried off in 

 the drainage water) and (2) to assist in nitrification by 

 forming calcium nitrate. For these reasons sulphate 

 of ammonia can only successfully be applied to soil 

 containing a sufficiency of calcium carbonate, and its 

 repeated application entails a considerable loss of lime 

 (equal to 100 of calcium carbonate for every 132 of 

 sulphate of ammonia applied, or if the lime required for 

 nitrification be included, twice this amount) in the 

 drainage water 



(NH 4 ) 2 S0 4 + CaC0 8 = CaS0 4 + (NH 4 ) 2 C0 3 and 

 (NH 4 ) 2 C0 3 + 40, + CaCOs = Ca(NO 3 ) 2 + 2CO 2 + 4H 2 O . 



* For later statistics see J. S.C.I. 1902, 146. t Jour. Soc. Chem. Ind. 1900, 87. 



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