AGRICULTURAL ENGINEERING. 931 



the junction of Gila and Salt rivers, a district which lies mostly within the Pima 

 Indian Reservation. This investigation lias been made for the purpose of ascertain- 

 ing the amount of water available for pumping, for irrigation by the Indians, and 

 the area in which such waters may be had." 



The paper reviews previous investigations, describes the geographic and other 

 physical features of the region, and gives data regarding wells, return waters, and 

 underflow, discussing incidentally the economic condition of the Indian tribes living 

 in this region as affected by the water supply. 



The water powers of Texas, T. U. Taylor ( U. S. Geol. Survey, Water-Supply and 

 Trrig. Paper No. 105, pp. 116, pis. 17, figs. 82). — This paper contains "a resume of 

 such data regarding water powers in the State of Texas as are at present available.'' 



Water powers of Alabama, with an appendix on stream measurements in 

 Mississippi, B. M. Hall | U. S. (•'ml. Survey, Water-Supply and Trrig. Paper Xo. 107, 

 pp. 253, pis. 9, figs. 9). 



British sewage works, M. N. Baker (New York: Engin. News Pub. Co., 1904, 

 pp. 149). — Descriptions are given of 24 existing municipal sewage works inspected 

 by the author in 1904, of the following classes: (1) 11 employing contact beds for 

 final treatment; (2) 5 employing percolating filters for final treatment; (3) 5 sewage 

 farms, and (4) 3 chemical precipitation works. Appendixes give notes on a sewage 

 settling and screening plant at. Wiesbaden, settling tanks at Frankfort-on-Main and 

 the sewage farms of Paris, and definitions or brief descriptions of typical processes 

 of sewage treatment. 



It was found that chemical precipitation is rapidly giving way to plain sedimenta- 

 tion and to septic tanks. "Sewage farming has by no means come to an end, 

 although in many instances it. is being abandoned as rapidly as local circumstances 

 will permit. Not a little of the apparent failure of sewage farming has been due to 

 the faulty methods employed as preliminary to the application of sewage to the 

 land. 



" Where the land available for sewage farming is defective in quality or deficient 

 in quantity it has been necessary to resort to a preliminary process of sedimentation, 

 chemical precipitation, or some method of filtration, and this necessity has furnished 

 the opportunity for exploiting the conceits of visionaries and of the proprietors of a 

 multitude of patented processes of sewage treatment. Most of these processes have 

 proved either futile or ruinously expensive, but too often the condemnation for their 

 failure has been heaped on sewage farming instead of on the preliminary treatment." 



The treatment of septic sewage, G. W. Rafter (New York.- 1>. Van Nostrand 

 Co., 1904, pp- 137). — This is a brief summary of the more important developments 

 in the treatment of sewage, with indications as to preferable methods of treatment. 



The purification of sewage, C. Duncan (Agr. Students' Gaz., n. ser., 12 (1904), 

 No. .', pp. 41-46). — This article discusses the bacteriological purification of sewage, 

 describing three experimental systems installed for the Worcestershire County 

 Council at Malvern Wells. 



A high-grade sewage farm (Amer. Cult., 66 (1904). No. 51, p. ■'>).— The success- 

 ful and profitable use of the sewage of Pasadena, California, on a walnut orchard is 

 described. 



The functions of various types of bacteria in the purification of sewage, 

 with some methods for their quantitative determination, II. W. Clark and 

 S. Dk M. Gage I Engin. News, 53 (1905), No. S, pp. 27-31).— This is a report based 

 upon investigations made at the Lawrence Experiment Station of the Massachusetts 

 State Board of Health. The various reactions involved in the bacterial purification 

 of sewage are described, and observations on the tendency of the sand from filters 

 to induce denitrirication, and the power of bacteria in sewage effluents and sands 

 from sewage filters to produce ammonia and nitrites in nitrate solutions are reported; 

 and methods of determining the ammonifying, denitrifying, nitrogen-liberating, and 



