1880.] 



Water supplies of Ccthutta. 



115 



In classifying these waters I have not separately considered the two 

 numbers I obtained by analysis for the total ammonia and chlorine, but 

 have decided on the character of each water from the amounts of both tliese 

 substances, and this table would therefore show the exact character which 

 I have attached to the waters which I have analysed. 



I scarcely think that it is necessary to criticise in detail the numbers 

 ■which I have obtained in these analyses. In some instances the results of 

 analyses showed that the tank and well waters are considerably more im- 

 pure than the very concentrated Calcutta sewage, which was collected at 

 the Pumping Station on December 18th, 1876, I have indeed never read in 

 any work or research of such horribly filthy waters as these are, and they 

 are waters which are now, or have been formerly used for domestic purposes 

 by many of the poorer inhabitants of Calcutta. 



Taking the numbers given in the foregoing tables, it may be said as a 

 general result of the whole of these analyses, that an average Calcutta tank 

 or well water contains 16"2 parts of total ammonia and 320 6 parts of 

 chlorine per million of water. This it will be remembered from one of the 

 previous tables, is if anything rather more impure tlian ordinary English 

 sewage as obtained and analysed by Prof. Wanklyn. In the table referred to 

 Prof. Wanklyn found in a sample of sewage 17'10 parts of Total Ammonia 

 and l^il'd) parts of Chlorine. We may also say that the average Calcutta 

 tank or well water contains more than 400 times as much organic nitrogenous 

 matter as is usually present in the hydrant water. 



I have, however, no wish to enlarge to any extent on this decidedly 

 nauseous topic, but perhaps the most striking condemnation of the well 

 and tank waters of Calcutta, and which will appeal to every inhabitant, 

 whether scientific or otherwise, is to say, that a good average quality of 

 Calcutta tank or shallow well water may be made, by mixing six parts of 

 our present hydrant water with from one to two parts of the most 

 concentrated Calcutta sewage. This artificial tank or well water will be of 

 about the average composition ; it will also be so far as can be judged, 

 equally healthy for potable and domestic purposes, and as for its taste, 

 odour, etc., it will probably be rather superior to the general run of Calcutta 

 tank and well waters. 



So far as I can ascertain this was tlie kind of water which was com- 

 monly used for drinking and domestic purposes in Calcutta in former days, 

 and wliich may to a certain extent be still used by the poorer inhabitants of 

 the northern quarter of the town. 



The present ivater supplij, i. e., the Hijdrant loater. 

 I need scarcely mention that our present hydrant water consists of the 

 Hooghly water pumped from the river at Pultah ; it is there collected in 



