40 Kansas Academy of Science. 



reason. However, at the time these analyses were made no Cre- 

 nothrix could be found in the Lawrence supply, but at certain 

 times of the year this supply is usually troubled with the growth. 



From what has been said one might be led to think that all 

 waters containing iron in considerable quantities contain man- 

 ganese also, but the waters having no manganese in the table 

 above were introduced to illustrate this point. 



All of the twenty-nine supplies examined contained more than 

 two parts per million of Fe203 + Al203. The best illustration of 

 waters with iron and no manganese are the Lucas waters. 



Table III. 



Parts per million 

 Fe^Os + Al.Os. 



No. 6 14.4 



No. 7 4 4 



No. 8 5.2 



No. 9 5 8 



No. 10 Not determined. 



The waters showing the greatest amount of manganese are the 

 ones whose sources are the water-bearing sands and gravel of the 

 Kaw river valley. 



It has been observed in the city water supplies along the Kaw 

 river that the rusty iron precipitate does not show up until the 

 supply has been in use for some time. 



At the present time the village of Bonner Springs is consider- 

 ing the abandonment of the present source on account of the 

 large amount of iron and manganese present, as the cost of main- 

 taining a filter plant or any other method of purification would be 

 too great. 



The plants longest in operation along the Kaw show the most 

 manganese. The Lawrence and Topeka works were put in opera- 

 tion about the same time. Wamego was next, with Bonner Springs 

 and St. Marys last, in the order given. The time is not far distant 

 when the larger towns will be compelled to put in operation some 

 form of purification other than settling the water, for at times 

 when the organic matter is high in the water scarcely any of the 

 iron is removed by the slight aeration and settling now given it. 

 The private wells in Topeka and Lawrence are so badly polluted 

 that a good supply will be demanded for domestic uses before 

 many years. 



N. B. — In the last volume of the Transactions of the American 

 Society of Civil Engineers (September 19, 1909), there is a com- 

 plete discussion of iron and manganese removal, as practiced in 

 this country and abroad, by Mr. Robert Spurr Weston. 



December 21, 1909. Water Survey Laboratory, University of Kansas. 



