1G8 DR. E. ANGUS SMITH ON 



tiful precipitant, and the water, when drawn from it, appears 

 perfectly pure. 



Mr. Higgs did not propose to deal with all the sewage 

 water of London, but only the portion about breakfast time. 

 The amount was too large to manage. That certainly will 

 be a diflBculty with London, with Manchester the difficulty is 

 much less, and a trifle, supposing the water closet drainage to 

 be separately treated. He proposed, also, to have rails over 

 the reservoir, so that persons might walk over it, throw down 

 the lime from waggons and stir it about. This makes the 

 matter still more difficult and expensive. Six tons of matter 

 were to be dried daily. 



The plan is well worth considering, and the lime is by no 

 means to be at once condemned, when used with proper pre- 

 cautions, although one chemist, Paulet, calls it a vicious 

 method which loses the ammonia and the salts of potash and 

 soda. The precipitate in the case he refers to consisted of 



Chalk 44.96 



Magnesia 1.32 



Phosphoric acid 40.18 



Organic matter 13.64 



Or loss by fire 100^ 



This I call rather a brilliant result; we are not given to 

 understand how much ammonia was in this organic matter, 

 but even were there none the amount of phosphoric acid is 

 worth preserving. The French practice so much boasted of 

 actually even now throws away the ammonia and alkaline 

 salts in the liquid which runs into the sewers, retaining only 

 that portion which drains from the dense mass which is trans- 

 ported to Bondy. The use of charcoal as a filter for sewage 

 water is not to be recommended, as little of value is removed. 

 The use of ordinary soil and clay as a precipitant would be 

 better, as they remove a great amount of valuable matter, but 

 this I think scarcely sufficient, although in some circustances 



