RURAL ENGINEERING. 585 



tigations are being continued with special reference to (1) the production of 

 active immunity in birds; and (2) the production of passive immunity in 

 rabbits." 



A bibliography is appended. 



Primary principles in the prevention and treatment of disease in poultry, 

 G. B. Morse (U. S. Dept. Agr. Yearbook J911, pp. 177-192).— The object of this 

 paper is to impress poultry raisers with the importance of cleanliness in main- 

 taining the health of poultry. The 7 primary principles outlined in the paper 

 previously noted (E. S. R., 24, p. 188) are emphasized. 



RURAL ENGINEERIITG. 



Irrig'ation investigations, G. E. P. Smith and F. C. Kelton (Arizona Sta. 

 Rpt. 1911, pp. 566-572, fig. 1). — Hydrographic investigations in the Sulphur 

 Springs, Rillito, and Santa Cruz valleys, carried on in cooperation with the 

 U. S. Geological Survey, are reported giving river discharge data, and data 

 relative to pumping plants and ground waters in the districts. A discussion 

 of the. application of the doctrine of priority in the use of underground waters 

 is appended, the following conclusions being drawn : 



" Priority in an underflow appropriation, then, ought not to be positive as it is 

 in the case of surface streams, but should be subject to limitations as follows: 

 (1) Any injury or interference must be proven clearly. (2) The injury nmst 

 be considerable. Trivial injury, or slight injury at infrequent or short periods 

 should not be cause for action. (3) A ditch owner must be reasonably willing 

 to cooperate with his neighbors in the general development of the underflow. 

 (4) A ditch owner must maintain his collecting head or flume in good condition 

 as an efficient agent for taking and carrying water." 



Measurement and distribution of irrigation water, L. M. Winsor ( Utah 

 Sta. Circ. 6, pp. 19-38, figs. .'/). — This circular gives the requirements for the 

 construction and installation of the Cippoletti trapezoidal weir with complete 

 end and bottom contractions and sharp crests, and gives directions and tables 

 for its use in the measurement and division of irrigation water. Brief discus- 

 sions are also given of time, division of water, and of the duty of water, with 

 a few definitions and hints to aid the irrigator. 



Possibilities and need of supplemental irrigation in the humid region, 

 M. B. Williams {U. S. Dept. Agr. Yearbook 1911, pp. 309-320, pis. 2).— In 

 treating this subject the author gives a brief historical note on the practice 

 of irrigation in the United States, points out the relation of rainfall to irri- 

 gation, together with the importance of supplemental irrigation, and describes 

 the possibilities and advantages of irrigation in the North Central, North At- 

 lantic, and Southern States. In addition to the methods of irrigation adapted to 

 the humid region and including surface irrigation, subsurface irrigation, and 

 spray irrigation are briefly noted, and the possibilities ancf need of irrigation 

 east of the Mississippi are pointed out. 



Helping out the rainfall, A. C. True (Pop. Mechanics, 17 (1912), No. J/, pp. 

 521-528, figs. 10). — This article deals with the value of irrigation as a supple- 

 ment to rainfall in regions suffering from droughts between wet seasons, and 

 discusses irrigation works and their benefits to general farming and truck 

 gardening in the Eastern and Southern States. 



The present outlook for irrigation farming, C. S. Scofield (U. 8. Dept. 

 Agr. Yearbook 1911, pp. 371-382). — Although irrigation farming has become 

 only recently an appreciable factor in American agriculture, the area has nearly 

 doubled in the last decade, there being 14,000,000 acres of irrigated land in the 

 United States at the time of the last census. The author finds that (1) the 

 price of irrigated land in the West is generally increasing, so that much of 



