AGRICULTURAL ENGINEERING. 395 



the primitive forms used by the primitive agriculturists. For example, 

 after trying all the complications of valves and pistons, of tight joints 

 and complicated motions, designers of machinery are in some instances 

 turning back to the old simple Persian wheel, which lifts water in 

 buckets with the minimum of friction and of load to be raised." 



Irrigation near Phoenix, Arizona, A. P. Davis ( Water Supply 

 and Irrigation Papers, U. S. Geological Survey, No. 2, p>>. 98, pis, 31, Jigs. 

 15). — In view of the importance of the storage of flood waters on a 

 large scale in connection with the development of the arid sections of 

 the United States, this bulletin undertakes to describe the situation as 

 regards this subject in the Salt and Gila River valleys, in which the 

 conditions are fairly typical. The topographic and climatic conditions 

 of these valleys and the irrigation works already constructed are 

 described, some of the systems now being introduced are outlined, and 

 the legal complications which have arisen are mentioned. 



The author "points out the great natural advantages of this country, 

 and shows, as far as data can be procured, the facts relating to water 

 supply, evaporation, silting of reservoirs, and other factors which 

 make or mar projects of water conservation." 



Sewage irrigation, G. W. Rafter [Water Supply and Irrigation 

 Papers, U. S. Geological Survey, No. 3, j>j>. 100, pis. 1. figs. 28). — It is 

 stated that the object of this paper is "to point out to American farm- 

 ers and to municipal authorities the fact that under certain conditions 

 sewage may be utilized with profit and to indicate in general terms how 

 this may be done." The principal topics discussed are: Importance of 

 sewage irrigation; general principles and definitions; quantity of sew 

 age from different cities; stream pollution; agricultural value of sew- 

 age; methods of disposal, including chemical precipitation, intermittent 

 filtration, and irrigation; sewage farming in England; sewage utiliza- 

 tion in Germany and France; and sewage purification in the United 

 States. 



The author believes that purification and utilization of sewage may 

 be successfully combined. To utilize sewage to the best advantage in 

 agriculture, provision should be made for intermittent filtration to 

 dispose of the sewage when not needed on crops. 



The actual fertilizing value of average sewage is stated to be from 1 

 to 2 cts. or perhaps 3 cts. per ton. Taking into account its value for 

 irrigation wheu rainfall is deficient, the total value may be taken as 

 2 to 4 cts. when the sewage is applied to the best advantage. Sewage 

 farming is of especial importance in the arid and semiarid parts of the 

 United States. 



Although the system has proved very successful abroad, it has not 

 generally been specially successful in the United States. This has 

 been due largely to improper management. The most notable exam- 

 ples of sewage utilization in the United States are probably Pullman, 

 Illinois; Los Angeles, California; South Framingham, Massachusetts; 

 Meriden and Bristol, Conuecticut, and Plainfield, New Jersey. 



