150 Treatment of Sewage with Basic Per- Salts of Iron. 



safeguard against sudden variations in the working of the 

 process caused either by inattention of those in charge, or 

 by actual change in the nature of the sewage. 



The time available for the experiments was not, 

 unfortunately, sufficient to fully determine whether the 

 increase of amount of precipitating material, or the 

 addition of a filtering or straining medium, would be the 

 most economical with a due regard to efficiency. 



A short period of experiment, however, would evidently 

 settle this point, and a future opportunity, either at Salford 

 or elsewhere, will no doubt present itself, in which case I 

 should be pleased to place the results before the Society. 



