Drinking- Water and some of its Impurities. 121 



almost invariably proceeds from the fermentation of urea 

 into ammonia carbonate, and is a sign that the water in 

 question consists of diluted urine. In these cases the water 

 will also be found to contain large quantities of chlorine. 



Ammonium salts are found in natural waters in exceed- 

 ingly small quantities. They do no particular harm in 

 themselves, but they frequently come directly from sewage. 



The annexed table shows the results of the analysis of 

 the water supplied to Schenectady, Troy and Albany. The 

 nitrites were reduced to nitrates and both appear under 

 that heading. Ammonium salts are represented by 

 organic nitrogen. The analyses were carried on under 

 the supervision of Prof. Perkins. The numbers represent 

 parts per 100,000 by weight. 



Trans, icc ] 



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