94 



A. Pedler — On the 'past and present 



[No. 2, 



In passing I may here remark, that a comparison of these numhers ' 

 with those of the previous table, shows that the present water supply of 

 Calcutta is really of excellent quality, and that very fevf of the good 

 waters selected from those given in the works alluded to, are as pui'e as 

 our hydrant water. That the purity of the hydrant water as determined 

 by this process of analysis is not merely exceptional, is clear from the 

 close agreement of the results of each year with the average of the four 

 years. It will also be noticed that the hydrant water will fall in class 

 one of Prof. Wanklyn's classification, as being a water of extraordinary 

 organic purity. 



On the other hand as examples of waters which are considered in 

 England to be exceptionally bad, and which are at once condemned as 

 sources of water for domestic purposes, and as examples of the results 

 obtained from sewage, I may quote the following from Prof. Wanklyn's 

 worli on water analysis. 





Total ammonia 



Chlorine parts 



Description of Water. 



parts per 



per million 





million of water. 



of water. 



Unfiltered Thames water at Hampton Court, 



0'32 



11-4 



Thames water at London Bridge, 

 "Well at Leek Workhouse (Staffordshu-e), 



2-11 



17-1 



0-36 



71 



Well in Windsor, 



1-28 



80-0 



Well in Eton, ... 



0-84 



800 



Pump in Drapers Hall, London, ... 



6-31 





„ ,, Bishopsgate St., London, 



7-75 





„ ,, Goodge St., London, 





177-0 



„ „ Oxford Market, 





474-3 



Sample of Sewage, 



17-10 



141-4 



In addition to these examples I have analysed the Calcutta sewage 

 by the same process. Thus on December 18th, 1877, samples of sewage were 

 collected at each hour from G a. m. to 6 p. m. at the Pumping Station, and 

 the amounts of total ammonia obtained from three of the samples showed 

 84-0, 87*0 and 145-6 parts per million of water. The average amount of 

 chlorine was 170"4 parts in the same volume. This shows a much more 

 concentrated sewage than that analysed by Prof. Wanklyn, but it is fair 

 to state that the three samples of Calcutta sewage were of extreme con- 

 centration, and of a most repulsive and disgusting character. 



If we take the first two tables above given as representing good drink- 

 ing waters, and the last as representing sewage, either dilute or concentrated 

 as the case may be, we are now in a position to understand the meaning 

 of the numbers obtained by the analyses of two hundred samples of 

 Calcutta tank and well waters, which are given in the tables below. 



