1866.] with the supply of water to Calcutta. 207 
Taste I, 
For 100,000 grs. For 70,000 grs. 
or Imp. gall. 
1865 
August 31st, 1865, including very fine clay,* Ebb, 12.13 8.41 
December 6th, Ebb, 24.00 16.80 
1866 
February 25th, Ebb, 30.00 21.00 
May 2nd, spring tide, Ebb, 386.20 25.34 
Flood, 88.50 61.95 
24th, Neap tide, Ebb, 21.25 14.88 
June 14th, spring tide, Ebb, 30.70 21.49 
Flood, 151.90 106.33 
July 6th, including very fine clay,* Ebb, 12.59 8.81 
August 8th, clay and some silica deducted, Ebb, 8.13 5.69 
These numbers confirm the results exhibited by Dr. Macnamara’s 
report, making allowance for difference of seasons. They shew clearly 
the increase of solid contents more especially during the dry season. 
And here I may remark that samples were chiefly taken during 
ebb tide, as my primary object was the examination of the river water 
proper, and it was only during the hot season that particular attention 
was paid to the state of tide, after my attention had been directed in 
part to what is the special object of this paper. And. indeed, except 
during the hot season, the composition of the water is little affected by 
the tides. 
And further, as the object was to make a full analysis of the water 
at several different seasons, I did not adopt the readiest or simplest 
methods of merely comparing the water at different periods for sanitary 
purposes, which would have been done, had that been my primary 
object. The methods adopted will be noticed in due course. 
The preceding table exhibits a very great variation in the amount 
of solid constituents during the hot season, owing to the influence of 
the tides, a subject which will be separately considered. 
* These waters had settled well—that of August 1865 for 19 days, that of 
July 1866 for about 35 days, yet by comparison with that of August 1866 
it will be observed that about one third of their solid contents was fine clay. 
26 
