MARSHALL O. LEIGHTON 



No. 4 is a turbid, highly colored water, with a moldy odor, a bad 

 free- albuminoid ratio (A), an appearance of nitrites, and high nitrates 

 (F) and chlorine. It is a thoroughly "suspicious "-looking water. 



No. 5 has practically the same characteristics as No. i. 



The object of introducing these tables is not so much to show 

 the misleading character of the data as to call attention to their 

 variations. Here are five analyses of a normal water, taken at the 

 same point from a small stream draining an uninhabited wilderness. 

 Yet only two of them possess a resemblance of uniformity, and the 

 free-albuminoid ratios va.ry from those of a dilute sewage to those 

 of a potable water. The variations in chlorine, too, are interesting, 

 and they lead one to speculate upon the actual normal chlorine 

 value for this region. The samples were taken from the head waters 

 of Green River in Casey County, Kentucky. 



SERIES " E." 

 PARTS PER MILLION. 



Series "E" presents several points of interest. Both waters 

 are of moderate color and turbidity, and have no odor. According 

 to the standards of interpretation, No. i is a recently polluted water. 

 It contains a large amount of nitrogen as albuminoid ammonia, 

 (A) and the free albuminoid ratio is i to 2. Free ammonia is very 

 high (D). Nitrites and nitrates (E and F) are both high. On the 

 whole, the water may be said to be both recently and remotely pol- 

 luted. No. 2, although somewhat similar, is superior in some respects. 

 The free-albuminoid ratio is i to 2.3. Free ammonia is the same, 

 while nitrites, nitrates, and chlorine are lower, though the last is 

 not significantly different. The fact that in No. 2 the albuminoid 

 ammonia is higher than No. i is responsible for the better ratio 

 in the former. 



One might readily infer that both samples were taken from the 



