i9o6.] Production of Sulphate of Ammonia. 359 



wasted or lost, to be used for feeding purposes. For instance, 

 in the case of a farm on which 1,500 cwt. of maize is consumed 

 annually, it is estimated that 1,500 cwt. of maize at 6s. per cwt. 

 would cost ^450. To produce 1,500 cwt. of dried potatoes 

 about 6,000 cwt, of raw potatoes would be required ; taking 

 the cost of drying at 4d. per cwt. the outlay would be ^100. 

 In addition, about 100 cwt. of cotton seed meal would be re- 

 quired to bring the feeding value of the dried potatoes up to 

 that of the maize ; this at 8s. per cwt. would cost ^40 ; 

 leaving a difference of ^310 as a return for potatoes, or about 

 IS. per cwt. It must be remembered that 20s. a ton is regarded 

 as an average value for the inferior potatoes used for industrial 

 purposes, so that the proposed method is thought to offer a 

 means of utilizing the whole surplus product for feeding on the 

 farm. 



The most important source from which compounds of 

 ammonia are obtained commercially is coal. When this is 

 treated for the production of coal-gas or 

 for the manufacture of coke used in iron 

 smelting, an " ammoniacal liquor " results 

 which forms the raw material for the 

 manufacture of ammonium salts. The distillation of the 

 bituminous shales used in the Scotch paraffin industry also 

 yields a certain amount, and the ammonia produced in iron 

 works where coal is used instead of coke is also collected. 



According to a return included in the Report of the Chief 

 Inspector of Alkali, &c.. Works for 1905, the amount of sulphate 

 of ammonia produced in the United Kingdom during the three 

 past years has been as follows : — 



Production of 

 Sulphate of 

 Ammonia. 





1905, 



1904. 



1903. 





Tons. 



Tons. 



Tons. 



Gas works 



155,957 



150,208 



149,489 



Iron works 



20,376 



19,568 



19,119 



Shale works 



46,344 



42,486 



37,353 



Coke oven works 



30,732 



20,848 



17,438 



Producer gas and carbonising works 







(bone and coal) ... 



15,705 



12,880 



10,265 





269,114 



245,990 



233,664 



There has been a considerable increase in the total production 



