51 



streams it is necessary to consider that the waters vary from 

 day to day and that no specific rules can be laid down for the 

 treatment. The results given are the averages. The analyses 

 which are marked (a) are average analyses covering a period 

 of one year, and were made by Mr. W. D. Collins, Assistant 

 Hydrographer of the United States Geological Survey, and Mr. 

 C. K, Calvert, Field Assistant of the United States Geological 

 Survey, under the cooperative agreement with the State Water 

 Survey, State Geological Survey, and the University of Illinois 

 Engineering Experiment Station in a study of the streams of 

 Illinois. 



The cost of treatment has been calculated on the basis of 

 lime at $6.00 per ton and soda at $1.00 per hundred. The cost 

 at any place can be readily calculated by noting the relation 

 between this estimated cost and the actual cost on the spot. 



The above illustrates one of the lines of work planned for 

 the survey. We wish to make analyses of all the supplies, and 

 we wish also some day to have the privilege of collecting our 

 own samples. 



As an illustration of the possibility of success in water 

 softening, I will mention an incident. My own cistern was 

 dry, so I arranged to treat 1,000 gallons of water. When I 

 was about to begin my wife expressed the wish that I ex- 

 periment on some one else. The experiment was carried out, 

 however. A few days later I was informed that the water I 

 had treated was better. A few days later my attention was 

 called to some curtains. "Don't they look nice? They were 

 washed in the water you treated." I had thus one convert to 

 water softening. 



