ON THE TREATMENT AND UTILIZATION OF SEWAGE. 



187 



in -whicli case the milk of lime -would not be added, and the clarified sewage 

 would still contain a quantity of phosphoric acid. 



The advantage of this use of it, if it were found to answer from an econo- 

 mical point of view, would be the deodorization of the deposit in the tanks 

 and of the sewage itself, which is certainly at present a great desideratum, 

 especially as regards the tanks. 



Section Y.—The Dry Earth System. 



The Committee did not consider that it was its duty to undertake the 

 examination of every plan that might be proposed for the treatment or i\ti- 

 lization of exeretal matters, but only those which were already well before 

 the public, and known, or supposed, to be affording something like satisfactory 

 results. It had sent out forms of questions with a view of procuring in- 

 formation respecting the results obtained in the use of Moule's earth- 

 closets, and there was every desire on the part of the Committee not to 

 neglect the examination of any system which promised results satisfactory to 

 the community. 



Of eight forms of questions sent out relating to Moule's system, only one 

 had been filled up and returned, and that one was from Lancaster. It ap- 

 peared that about 2| lbs. of soil were used per head per day. The manure 

 obtained is afterwards mixed with other town refuse, and the mixture is sold 

 at 5s. a ton. The analysis of the manure published by the Rivers Pollution 

 Commission showed, however, that it did not contain more nitrogen than 

 good garden-mould. It was stated to have been applied at the rate of about 

 6 tons per acre to grass land ; but the produce of hay was by no means large. 

 It should be added, however, that even at Lancaster, the only place where an 

 attempt has been made to carry out the system on a large scale, some of the 

 conditions prescribed by Mr. Moule, and essential to its success as a means of 

 avoiding nuisance and injury to health, are entirely neglected. • Thus there 

 is an average of twenty-four persons using each closet ; and instead of any 

 arrangement for the deposit of earth on the fsecal matters after every use of 

 the closet, a quantity of soil is thrown once a day over the matters collected ; 

 and the result is, that the product is removed in a very offensive condition. 



On behalf of the Committee, Dr. Gilbert has himself made some trials "with 

 Moule's earth system: 14 cwt. of air-dried and sifted clayey soil were set 

 apart for the experiment. Prom one third to one half of the whole was used 

 before it was necessary to empty the pit. When removed the mass appeared 

 uniformly moist throughout, and (excepting in the case of the most recent 

 portions near the surface) neither fascal matter nor paper was observable in it ; 

 nor was the process of emptying accompanied by any offensive smeU. After 

 exposure and occasional turning over on the floor of a shed, the once-used 

 soil was resitted, and again passed through the closet. 



Below are given the percentages of moisture and of nitrogen in the soil 

 under the various circumstances of the trial : — 



Calculated upon the air-dried condition, the increase in the percentage of 



