134 CONSTRUCTION AND MANAGEMENT OF SMALL GASWORKS. 



manner as in the ordinary saturator. As in the ordinary 

 manufacture of sulphate, care must be taken to maintain 

 an excess of acid, but a much lower proportion. The excess 

 must not be greater than a strength represented by 3 

 Twaddel. To secure this result, small quantities of acid 

 are added at frequent intervals through a tapped U-tube 

 and funnel. This looks like an elaborate business, but in 



after possirig, cone/e 

 and simp/e far extractor 



Sulphate Plant at Wareham Gasworks. . 



practice is as easily managed, with the aid of litmus paper 

 and an hydrometer, as the working of the ordinary 

 saturator. Any ammonia in the gas is readily absorbed 

 by the weak acid, and sulphate gradually accumulates in 

 the liquid. The presence of the salt is no objection so 



