1866.] with the supply of water to Calcutta. 233 
Taste V. 
For 100,000 fluid grains. 
Date of col- | Solid | Organic ; Oxygen |Ammoe 
lecting. matter. | matter. | reqd. to | nia. 
1866. oxidise. 
General’s Tank, ...(6 June, | 12.05} 1.35} .0825) .235 
14 Aug. 1225 
Monohur Doss’s Tank, ...,l4 May, | 24.60} 2.00) .0913 
6 June, .1000 
14 Aug. 1400) .204 
Dalhousie Square Tank, ...,14 May, | 23.85} 1.50 
6 June, 25.80, .0750 
Cornwallis Square Tank, : 
settled and veg. matter de- 
posited, ...{14 May, | 58.00) 4.40) .1550 
not settled, 14 Aug, 5.15 
Dhurrumtollah Tank, ... Aug. 2975) .237 
Barnagore, .».(11 May, | 51.00} 4.25) .38170 
8 June, .2938 
17 Aug. 3375 
Dhurrumtollah well, Hoole ibis 0725 
Barnagore well, softs) eames. .0900 
Salt Water Lake, 
from Canal at Dhappa Toll 
House, ... {13 June, | 908.00} 20.00} .1250 
Ditch conveying sewerage of 
Calcutta, ...{L June, | 295.80} 33.10) 5.680 
* Ditto, 18 Sept. 27.33 
* Ditto, ... 13 Sept. 22.25 
On examining this table, it will be observed that even the best tank 
water contains more organic matter by weight, and requires more 
oxygen to oxydise it than does the river water during ebb tide; even 
Dalhousie Square water appears to deteriorate by being removed 
from the running stream into a stagnant reservoir. The excess of 
organic matter in the bad tanks is also very noticeable. The two 
well waters require more oxygen than the river water generally. 
* Added since the date of the paper. 
