286 EXPERIMENT STATION BECOED. [Vol.35 



cotton, sorghum, and tur (pigeon peas), the irrigated plats showed superiority 

 in yield over nonirrigated plats in a dry year, but the Irrigation did not " finan- 

 cially show any benefit from the economic standpoint." 



Venturi meter developed for accurate measurement of irrigation water, 

 A. A. Wood (Engin. Rec, 13 (1916), No. 13, pp. J,ll-413, figs. 3).— A recording 

 device, applying the Venturi meter principle, is described which is designed to 

 establish rates on an equitable basis for water users. It is thought that by 

 its use the flat-rate system of charges may be eliminated. 



Swamp-land drainage with special reference to Minnesota, B, Palmeb 

 {Univ. Minn., Studies Soc. Sci., No. 5 (1915), pp. 138). — This report contains 

 a brief statement relative to the drainage work in foreign countries, the extent 

 of land needing drainage in the United States, drainage laws and development 

 of drainage legislation in Jlinnesota, drainage procedure, and the extent of 

 swamp-land reclamation in Minnesota. As an appendix is given the drainage 

 statutes of various States and references to drainage cases in the ftlinnesota 

 Supreme Court. A statistical table showing the land in need of drainage, the 

 area drained, and the cost and average net profit per acre as result of drainage, 

 together with a brief bibliography, is included. 



Land bedding as a method of drainage in the Gulf coast region of Texas, 

 E. W. Geuss (Agr. and Mech. Col. Tex. Ext. Serv. Bui. B-11 (1915), pp. 6).— 

 This method is briefly described. 



Tile drainage by day labor and by the rod (Engin. News, 75 (1916), No. 10, 

 pp. 450-Jf52. figs. 5). — This article describes a land drainage system on the 

 Mississippi River built for three landowners jointly, the work being done by day 

 labor under the direction of the engineer. 



Experiments with the automatic water finder in the trap region of western 

 India, H. H. Mann (Dejtt. Agr. Bombay Bui. 72 (1915), pp. 17, pis. 3).— The 

 results of the experience of others along this line are noted and tests are 

 reported of a so-called automatic water finder. 



This finder consists of a wooden case divided into two chambers, the lower 

 containing coils of wire wound on a bobbin, and the upper, at the center, a 

 pivot on which rests a light magnetic needle, which, by its movements, is sup- 

 posed to detect underground streams. With the instrument are provided a 

 tripod stand and a table on which the instrument is to be placed while taking 

 an observation. On the table there is a white line which is always to be 

 directed toward the magnetic north while using the instrument. " It is ohvious 

 that what the instrument detects is not the stream of water, but some electric 

 condition which accompanies that stream." 



The results of a large number of tests at different places indicated that 

 " where a stream of water is known to exist the indications of the instrumeiit 

 are by no means constant and the deflection of the needle may vary in direction 

 as well as in amount." 



... It would seem, however, sufficiently proved that under the conditions 

 which prevail in the trap areas of western India, where underground water 

 occurs in well-defined streams flowing in rock fissures, sometimes under little 

 or no pi'essure and sometimes under considerable pressure, the automatic water 

 tinder can be used with advantage in locating streams of water which can be 

 tapped either by well digging or by boring." 



The conditions affecting the accuracy of the instrument and the precautious 

 to be observed in its use are explained. 



Investigation of the pollution and sanitary conditions of the Potomac 

 watershed, H. S. Cujiming et al. (Pub. Health Serv. U. S., Uyg. Lab. Bui. lOi 

 (1916), pp. 231, pis. 50). — This report is the result of an investigation of the 

 pollution of the I'otomac River and its tributaries begun June 2, 1913, and 



