220 Mr. Waldle's investigations connected [No. 3, 



9th December, 1865, Ebb, Surface, 1.02 



Deep, 78 .0175 



25th February, 1866 Ebb, Surface, 92 



Deep, 45 



2nd May, Ebb at Bankshall, southern part of 



Calcutta, , .0325 



Flood at Hatkolah, northern part of Calcutta,... 2.70 



30th May, Ebb, 90 .0238 



Flood, 2.60 .0275 



14th June, Ebb, 90 .0250 



Flood, .. 2.20 .0225 



6th June at Chandernagore, 20 miles above 



Calcutta, Ebb, Surface, ... .60 .0163 



Deep, 67 .0213 



From an inspection of this table, it will be observed that the 

 permanganate test exhibits the largest quantity of organic matter in 

 the river water during the rainy season, and the smallest quantity 

 during the cold season, the hot season giving results intermediate.* 

 The same ratio is not so distinctly perceptible in the weight of the 

 organic matter. If the water at all these seasons were at the same 

 state of dilution as regards saline matter, there would be the largest 

 proportion of organic matter during the rainy season and the smallest 

 during the hot season. The hot season is usually associated with ideas 

 of corruption and concentration of impurities, the rainy season with 

 purification by the abundance of pure water from the clouds. In 

 point of fact it is directly the reverse. The same thing has been 

 observed in England, as will be manifest from the following quotation 

 from Dr. Frankland's report on the London waters. He says, " This 



* It was with considerable hesitation that I left the indications given by 

 the permanganate test in the table, on account of objections raised to my 

 determinations of the organic matter which led to a supplementary paper read 

 at the succeeding meeting of the Society. But after due consideration, they 

 were allowed to remain as sufficient for the purpose required. The objections 

 will be noticed as occasion calls for it, in notes or in the Supplement. 



It is to be observed also that, as reported in the Proceedings of the Society 

 for October, page 1866, 1 had stated 1.4 grains per gallon as the largest amount 

 of organic matter obtained. Two of the results in the table, those of 2nd and 

 30th May somewhat exceed this, viz. 2.7 and 2.6 grains corresponding respective- 

 ly to 1.89 and 1.82 grain per gallon. The correctness of these was doubted from 

 supposed inaccuracy in the process, but this not being certain they have been 

 introduced into the table. 30th Nov. 1866. 





