1867,] 



ivith the supply of water to Calcutta. 



127 



Canals, I am informed by the town surveyor, Mr. Howe, receive by far 

 the largest proportion of the sewerage of Calcutta, the course of 

 drainage, except for a narrow space along the river, being towards 

 the east, or from the river towards the lake ; so to these sources of 

 supply I went for specimens of impure water, The Canal water flows 

 eastward or westward according to the relative height of tide in the 

 Hooghly or Bidyadurrea with which it communicates. The follow- 

 ing table gives the results of the examinations. 



Table VI. 

 For 100,000 fl. grs. filtered water. 



Salt Water Lake and Circular canal. 



Total solid 



Organic 





matter. 



matter. 





grains. 



grains. 



Water flowing from the Circular Canal at 





* 



Chitpore bridge into the river on 14th Feb- 







ruary, 1867, Neap tide, ebbing commenced. 



471.70 



15.30 



Water from Baliaghatta canal at Dhappa Toll 







House, 18th February, 1867, 



489.50 



6.00 



Water from the Marsh taken at same time, . . . 



525.00 



6.50 



From Circular canal at junction with the 







Entally canal, water flowing from the river 







24th November, 1866. Filtered, 



40.40 



*1.75 



,, ,, Ditto, 





2.48 



Cleared by per-chloride of iron and filtered, ... 



42.60 



2.51 



Ditto, 





2.58 



From Circular canal at bridge on Dum-Dum 







road, full tide, 20th February, 1867, 



32.95 



1.78 



From the mouth of the canal at same time, . . . 



34.90 



1.53 



The most remarkable thing exhibited by the table is the small 

 quantity of organic matter in these waters. The excess in the case of 

 the 14th February water, was, there can be little doubt, owing to the 

 water having traversed the whole length of the circular canal, passing 

 over its putrid mud and carrying with it the sewerage from the 

 numerous drains which enter it. The small quantity of organic 

 matter in the filthy looking water of the marsh, full of gelatinous 



* Probably some unobserved error in this case. 



