66 A Solution of the Sewage Problem. [January, 



so as to afford room for the construction of a subway in such 

 a manner as to place the sheet of water — as clear as plate- 

 glass — between the visitor and the diffused light of the sky. 

 In this position the transparency of the water is subjected to 

 a most severe test, leaving no doubt as to the previous 

 subsidence of all solid particles. The effluent water is run 

 off to the Thames in a shallow brick-built conduit, about 

 4 feet wide by 270 feet in length, and arranged during its 

 course to form several miniature cascades. 



During an official trial, lately completed, extending over 

 eighty days, there were used 80 tons of dry ABC materials, 

 whilst the " native guano " obtained amounted, in the dry 

 state, to 131 tons, showing an increase of more than 63 per 

 cent. The amount of sewage treated during this time was 

 11,672,000 gallons. Therefore 1 ton of dry native guano 

 was obtained from 89,100 gallons of the Crossness sewage. 



The Crossness works are calculated to have cost the Com- 

 pany considerably more than it would be necessary to expend 

 upon any works dealing with much larger quantities of 

 sewage ; but it is estimated that /5000 would amply re- 

 munerate the contractors for works which should deal with 

 the sewage of 20,000 inhabitants, and that £1000 additional 

 capital would provide for the working expenses. This, 

 however, is not a matter with which we have to deal in 

 detail. 



The state of the effluent water may be viewed from two 

 points — that of an analytical chemist, and that of a prac- 

 tical man of the world. The former can, without difficulty, 

 make out a case which would lead persons ignorant of the 

 weakness of purely chemical reasoning to condemn any water 

 in the world ; and a sensation is readily created by manipu- 

 lating figures in such a way as to convert grains of the normal 

 constituents of a good drinking water into tons of impurities, 

 and by classifying perfectly innocuous substances under the 

 fearful title of " previous sewage contamination." 



Common sense leads one to judge of a water by other 

 standards than those of theoretical chemistry. The effluent 

 water from sewage purified by the ABC process, falling 

 into the Thames at Crossness, into the Aire at Leeds, into 

 the Croal at Bolton, and into the Seine at Paris, may not at 

 all times come up to the fanciful requirements of a scientific 

 chemist, — although the inhabitants of many towns and vil- 

 lages habitually use and thrive upon a worse water — but no 

 intelligent man of the world will doubt its suitability for 

 admixture with ordinary river water. It is perfectly limpid 

 and colourless ; it has no smell, and so little taste that were 



