1866.] Proceedings of the Asiatic Society. 219 



sides, comparing the sewage of Calcutta with the volume of water in 

 the river, its proportion must be insignificant. An examination of 

 some tank and river waters immediately after collection, and at about 

 two weeks interval or longer, indicated the same thing, a loss of from 

 about 10 to 25 per cent., which would not increase the author's esti- 

 mates more than about half a grain per gallon. 



Mr. W. further observed that perhaps a quotation of other results 

 than his own might have more weight, and again referred to Dr. 

 Frankland's analysis of the London waters for the largest amount of 

 organic matter, — about 2 J grains per gallon, — found in the worst case ; 

 and to the general observations of the Metropolitan Medical Officers 

 of Health agreeing with Dr. Frankland's. He further referred to Messrs. 

 Lawes and Gilbert's analysis of the sewage of Rugby &c, (in the paper 

 formerly quoted,) who found in the river Wandle, after it had received 

 the sewage of Croydon, little more than 2 grains per gallon of organic 

 matter, and in the liquid part of the sewage of Rugby only from about 

 7 to 8 J grains of organic matter per gallon. So that if the river water 

 in May and June contain about 8 grains organic matter per gallon, and 

 this excess derived from the Calcutta sewage, it must be as bad during 

 these months, in regard to organic matter, as the liquid part of the sewage 

 of Rugby, a supposition in the author's opinion altogether incredible. 

 He further observed that there was no way of reconciling the dis- 

 crepancy, (if there was no considerable error in the analyses,) but by 

 supposing, during the hot season, the presence in the water of a con- 

 siderable quantity of organic matter, possessing no bad smell, but capa- 

 ble of undergoing rapid decomposition. He could not deny the possibi- 

 lity of this, but had seen no reason to believe it, while he had reasons 

 for thinking it highly improbable. The point could only be decided 

 positively by further examination at the proper season. He intended 

 to prosecute the investigation, and hoped at another opportunity to lay 

 the results before the Society. 



Dr. Smith regretted that Mr. Waldie had not favoured the Society, 

 at the close of his communication, with an epitome of the exact con- 

 clusions he had arrived at. The paper had been read on two different 

 occasions — or rather two distinct essays had been read, with the 

 interval of a montli between them. Dr. S k hoped therefore Mr. Waldie 



