1866.] with the supply of water to Calcutta. 227 



carefully examining wherein they lie, in order to see if they can "be 

 avoided. Yet notwithstanding these inaccuracies, it seems to me 

 that the general results are pretty evident, that the amount of 

 ammonia is greatest in the rainy season, diminishes during the cold 

 one, and again increases during the hot, which increase, however, is 

 probably not in the river water proper. One examination of water 

 from Chandernagore, which was very slightly if at all contaminated 

 with tidal water, yielded only .0118 grain ammonia in 100,000 flood 

 grains. This conclusion is not a certain one ; to make it so, it would 

 be necessary to have examinations of the Chandernagore water at all 

 seasons ; but other considerations, to be afterwards noticed, render it 

 probable.* 



I am disposed to attach a good deal of importance to the estimation 

 of the ammonia, not only because it helps to indicate how far the 

 nitrogenous matter has gone in the stage of decomposition, but because 

 that stage is not improbably one of importance. It has been long 

 known that many, I may say most, of the organic proximate principles 

 found in vegetables are alkaloids possessing active properties and 

 producing the most marked physiological effects, and that there are 

 many similar principles produced in the decomposition of nitrogenised 

 substances by destructive distillation or otherwise, which possess marked 

 physical properties, and probably, if they were examined, also decided 

 physiological actions. But by modern chemical research, it would 

 appear that these alkaloids are all formed on the type of ammonia, 

 or are ammonias having one or more atoms of its hydrogen replaced 

 by some other organic combination or radical. Hence it seems not at 

 all unlikely that such compound ammonias as they are called may be 

 produced at the same time and along with the ultimate or ordinary 

 ammonia. And even though no such compounds should exist, the 

 amount of ammonia would give some probable indication of the stage 

 of decomposition, and existence of compounds is a state of transition 

 towards ammonia. 



* The examinations for ammonia were all made about the same time in the 

 month of August, consequently the waters were of different ages. The samples 

 had been preserved mixed with a little Hydrochloric acid and mostly in a 

 concentrated state. Of course objections may be made to their value on this 

 account and possibly may be valid. This will again be referred to in the sequel. 

 3uth November, 1866. 



