THE DISPOSAL AND UTILIZATION OF KKS1DUALS. 133 



soda is added to decompose the fixed ammonia, but it is 

 rarely practicable to give the liquor sufficient boiling to 

 get the full advantage. A boiling of several hours is 

 required to effect the complete decomposition of the fixed 

 ammonia. Lime gives trouble from deposits in the boiler 

 and settling tanks, and soda is costly, and I question whether 

 it is much advantage on the small scale. I have found as 

 good results without it as with it, and I think that in many 

 small works where it is used the result of a test of the 

 spent liquor would show that the decomposition of the 

 fixed ammonia is far from complete. In large towns, 

 there is some difficulty in disposing of the spent liquor, 

 but this trouble rarely arises in the country. 



The art of making sulphate is not easily learnt from 

 books. A beginner at it is strongly urged to spend a day 

 or two at the nearest sulphate works, and to carefully watch 

 the operation from first to last. 



This portion of the subject would not be complete 

 without some reference to a paper read by Mr. P. G. G. 

 Moon, of Bournemouth, at a meeting of the Southern 

 District Association of Gas Engineers (see THE GAS 

 WORLD, i2th November 1910, p. 585). This describes a 

 simple method for the direct production of sulphate, as in 

 use at Wareham, and also a process for dealing with the 

 whole of the ammonia produced, as in use at Dunstable 

 and elsewhere. I am informed by the makers (the 

 Chemical Engineering Company and Wilton's Patent 

 Furnace Company) that the approximate cost of the Ware- 

 ham plant is ^"50 and of the Dunstable complete set ^100. 

 The difference between this and the ordinary process is that 

 the gas, freed from tar, but containing ammonia, is passed 

 through weak acid contained in a lead-lined washer, and 

 here a solution of sulphate is gradually formed, in the same 



