68 Proceedings of the Asiatic Society. [April, 



obtained was 2.7 grains per 100,000 grains, or rather less than 2 

 grains per gallon. 



" Another table exhibits the amount of organic matter in the water 

 of the Salt Water Lake and Circular canal. On the 18th February the 

 water of the marsh contained only 6.5 grains per 100,000 grains or 

 4.55 grains per gallon. A calculation made on data supplied by Mr. 

 Leonard (reduced to one half on account of uncertainty) or 5000 

 ft. per second of water flowing in the river at the minimum, shew 

 that though Mr. Clark's supply of 6,000,000 gallons of water per day 

 flowed into the river in as concentrated a state of impurity as the 

 filthiest ditches of Calcutta during the hot season, it would add of 

 organic matter to the river water only to the extent of 5 or 6 

 hundredths of a grain per gallon. The allowance is extravagant, yet 

 the addition is but small. 



" Trials for Ammonia, exhibited in tables, shew that the water during 

 the cold season is at its purest, and other observations on the organic 

 matter are confirmatory of those previously made. 



" Further observations on the tank waters confirm the conclusions 

 formerly drawn. Additional samples have been examined in the 

 northern part of the town, with reference to a tank proposed to be 

 excavated there by the Municipality. All the tank waters examined, 

 except those of the Maidan tanks and Dalhousie Square Tank, 

 contained much more saline matter and were much harder both before 

 and after boiling than the river water at its worst (except as regards 

 salt during flood tide in May and June,) and contained much more 

 organic matter, — two, three, or four times as much. The water of the 

 street aqueduct (from the river) was greatly superior in every respect. 

 Water obtained from temporary wells dug for the purpose was care- 

 fully analysed and found to be simply sewage water, deprived of the 

 greater part of its bad smell by passing through the earth ; indicating 

 that the soil is more or less penetrated by sewage water all over the 

 town. 



" Further consideration had been given to the nature of the organic 

 matter, -confirmatory of former observations. The organic matter in 

 the river water during the rainy season was analagous to that of tank 

 water, and contained a larger proportion of vegetable matter than that 

 of the dry season. But it by no means followed that it was less 



