THE 



UTILITY OF SULPHATE OF AMMONIA 



IN 



AGRICULTURE. 



More than half a century ago, in dealing with the subject 

 of the " Food of Plants," Fownes wrote as follows : "I beg 

 once more to call attention to the salts of ammonia. Should 

 these really be found to produce the beneficial effects antici- 

 pated, we shall possess at home, within the limits of our own 

 island, resources for the improvement of agriculture com- 

 pared with which guano, and nitrate of soda, and all such 

 things, are quite insignificant resources which only require 

 to be judiciously used to produce the most extraordinary 

 results."* 



This prediction was made when the value of nitrogenous 

 manures was very little understood, and when artificial top- 

 dressings in particular were undergoing their first trials, and 

 were regarded with great suspicion by the majority of agricul- 

 turists. Subsequent discovery and research have proved the 

 general correctness of the forecast, though the judicious use 

 of salts of ammonia is not met with as often as might be. 

 It is the object of this essay to point out the manner of 

 action of sulphate of ammonia ; and, relying only on results 

 of actual experiments, to show how it may best be used on 

 the various crops of the farm with a view to profit. 



MANUFACTURE OF SULPHATE OF AMMONIA. 



Sulphate of ammonia, in common with other compounds 

 of ammonia, is obtained chiefly as a bye-product in the 

 manufacture of coal gas. When coal is heated in the retorts 

 to drive off the gas, most of the nitrogen it contains com- 

 bines with hydrogen, also found in the coal, to form ammonia 

 a gas consisting of fourteen parts by weight of nitrogen, 

 and three parts of hydrogen. To remove this ammonia 

 from the coal gas, in which it would be a harmful ingre- 

 dient, the mixture is usually brought into contact with 

 water in a special apparatus called a " scrubber," when the 

 ammonia is dissolved, while the rest of the gas passes on. 



* " Journal of the Royal Agricultural Society of England," Vol. IV. 



