FUTILITY OF A SANITARY WATER ANALYSIS 



condition at the time of analysis (C and D). The ammonias are 

 low, and (A) the free- albuminoid ratio is excellent. (F) It would 

 appear from the large amount of nitrates and the high chlorine 

 that the water has at some time been polluted, but has become 

 well purified. Nos. 3 and 4 are waters that have been in bad 

 "company" (F), and the free- albuminoid ratios, especially that of 

 No. 3, show recent pollution (A). No. 5 (see high nitrates and chlo- 

 rine) appears to be an excellent example of a water purified by run- 

 ning in a stream-bed through a long stretch of unoccupied country 

 below some initial seat of infection. Note the high nitrates. The truth 

 is that all these waters were taken from unpolluted streams in the 

 mountain districts of the Potomac drainage area in Virginia and 

 West Virginia. 



SERIES "D." 

 PARTS PER MILLION. 



Analysis No. i, in Series "D," indicates a practically colorless 

 and odorless water, with nitrogen in all four forms low in amount. 

 The chlorine, too, is low and practically, the only suspicious feature 

 about the statement is the free-albuminoid ratio (A). 



No. 2 is a turbid water of moderate color. The amount of nitro- 

 gen as albuminoid ammonia is high, but the free-albuminoid ratio 

 ("A," last part) is 1:7. (F) Nitrogen as nitrates is high. It is not 

 a very bad water according to the interpretation, yet there are evi- 

 dences that some swamps are tributary to the point at which it was 

 taken. 



No. 3 looks suspicious because of the free-albuminoid ratio (A), 

 the moderately high free ammonia (D) and nitrates (F), and the 

 high chlorine. 



