SEWAGE AND SEWAGE RIVERS. 165 



ficulty attending all the liquid manure plans, it is that of 

 getting suitable land and sufficiently extensive near towns. 

 I confess I am unable to argue this well, but I am inclined 

 to think that the manure is so abundant that it will readily 

 supply persons to a great distance. If the water closet 

 sewers are kept distinct, it is probable that precipitation and 

 preparation would be essential, as the manure would not be 

 in a fit state to put on land without loss and nuisance ; but 

 if the sewer water remain as it is, the distance of carriage 

 and the amount to be put on land seem to be great difficul- 

 ties, quite insuperable in the way of applying all the refuse 

 matter of a large city. If, again, all of it is not applied, 

 there is no advantage in having any portion applied, as far 

 as the purity of the stream is concerned; at least it is not 

 for us to waste our time thinking on merely a small diminu- 

 tion of the evil. 



It has been proposed, also, to take the sewage into a reser- 

 voir, and allow it to precipitate. This is the method adopted 

 with the contents of cesspools at Paris, but there the matter 

 is undiluted, and even of that the densest portion only is 

 taken, leaving the liquid to be run off into the sewers. The 

 poudrette formed is not of great value, and sells for much less 

 than our artificial manures, about a pound a ton. The de- 

 posit in sewer water ponds was found, in an- instance men- 

 tioned by Smith of Deanston, to be worth very little. It 

 was sold for one shilling a ton, but the analysis and especially 

 the amount of phosphates is wanting to determine its real 

 worth. 



Leaving that aside, the matter valuable for manure is not 

 in suspension merely, and cannot therefore be obtained by 

 subsidence only. For these reasons it has been proposed to 

 filter the sewage water, and this method certainly produces 

 very fair water in appearance, and leaves a great amount of 

 valuable manure in the filter. But the oxidizing power of 

 the soil and of porous bodies is the cause of much waste of 



