lOO KANSAS UNIVERSITY QUARTERLY. 



An interesting series of experiments was also made on a reach of 

 the river about thirty-two miles in length; that between Topeka and 

 Lawrence. This was done in April, 1893. The results were as fol- 

 lows: — 



Above Topeka 10.73 0008. 0132 



At Topeka, below bridge lo- 73 0008. 0132 



At Tecumseh, 5 miles 10.50 0018 0130 



At Lecompton, 12 miles further 1 1.29 0005 . .0138 



At Lawrence, pumping house 10.98 0028 0134 



At the winter stage of the river the examination showed the fol- 

 lowing: — 



Above Topeka 0017 0186 



At Big Bend 0010 0132 



At Lawrence, 4 miles above dam 0005 0170 



At Lawrence Water Works 0004 0250 



In this case it can be seen that there is a gradual purification of the 

 river, after it has received the sewage of the city of Topeka, and 

 that suddenly the albuminoid ammonia in one case and the free 

 ammonia in the other rise very much in (piantity. This is not an 

 accidental result, but has been confirmed by numerous analyses. The 

 large increase of albuminoid and free ammonia is accounted for by 

 a microscopic examination of the water, in which it is revealed that 

 there is a growth of diatoms in the slack water above the dam. 

 These are not found in any quantity above the point three miles up 

 the stream, where one of the samples was taken. The water is by no 

 means quiet for three miles above the dam, but the current is impeded 

 just enough, and the stream is deepened, so that these lower forms of 

 life appear. 



It is not difficult to trace the organic material of the upper tributar- 

 ies of the Ka_w, and indeed of the whole system, to its source. Inves- 

 tigation shows that there are numerous cattle pens and slaughter 

 houses on the banks, and that in the small towns much of the organic 

 refuse of the dwellings finally finds its way into the river. Hog wal- 

 lows are very numerous also, and a great deal of this accumulated 

 filth is flushed into the rivers at high water. To this may be added 

 the sewage of the cities, but this is really small in comparison to the 

 total flow of water. 



In this connection it is important to notice that in this region the 

 determination of chlorin is utterly valueless as an index of the purity 

 or the impurity of a water supply. As an illustration of the effect of 

 sewage, an examination was made of the Topeka sewage itself, and it 

 was found to contain only 16.46 parts of chlorin per 100,000, or only 



