CHAS. E. FOWLER. 289 



years but nevertheless have escaped ; and during the 

 past fifteen years no water has been pumped to the city 

 that has not passed through the filter-beds. 



The efficiency of these beds, when in good order, is 

 shown chemically in the following analyses made by 

 Professor Drown, in June, 1893. These results being the 

 averages of nine analyses of river water at the intake 

 and of six analyses of the water taken at the same date 

 from the clear water basin of the filter-beds : 



Parts in 100,000. 



Intake. Clear Water Basin. 



Albuminoid Ammonia, 0.144 0.0089 



Free " 0.0031 0.0001 



Nitrogen as Nitrites, 0.0007 0.00003 



" " Nitrates, 0.0108 0.0151 



Oxygen consumed, 0.5197 0.3677 



Chlorine, 0.1100 0.1110 



We observe that nitrification or the reduction of am- 

 monias and nitrites accompanied by an increase of nitrates 

 has taken place to a very material extent, indicating that 

 a large portion of the organic matter present has passed 

 into a mineral condition. What has caused the change 

 I do not know. From another analysis we find the 



following : 



Inlet Basin. Clear Water Basin. 



Albuminoid Ammonia, .0158 .0096 



Free " .0000 .0000 



Nitrites, .0001 .0000 



Nitrates, .0100 .0150 



Bacteria per cubic centimeter, 1576 34 



In this we note the same redaction of ammonia and 

 nitrites and a greater increase of nitrates. We note also 

 a reduction of 97.7 per cent, of bacteria. 



Whether nitrification has caused the destruction of the 

 bacteria or the destruction of the bacteria has produced 

 the increase of nitrates or if they are independent of 

 each other I do not know. 



We have not as yet adopted the practice of having 



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