I 



1820] RURAL ENGINEERING. 787 



intestinal stage derived from lamb 27. The heavy degree of infection of throe 

 out of four of these lambs and the medium infection of the other indicates 

 that they were probably reinfected from their own feces. All the above con- 

 ditions of infection, in all of the experiments described, conform best to the 

 theory of an infective intestinal stage. While not directly proved, there ai)pears 

 to be no reasonable doubt about accepting this hypothesis as an adequate ex- 

 planation of a part of the life cycle of S. tcnella. 



"Control measures are suggested based on the theory that infection results 

 from eating food contaminated with infective feces. 



Hog cholera, R. It. Birch {Cornell Reading Course for the Farm, No. 150 

 (1919), pp. 117-136, figs. 6). — The essential facts concerning hog cholera and 

 measures for its control are presented in nontechnical terms. 



Infectious anemia of the horse, LChrs (Ztschr. Veterinarlc, 31 {1019), 

 Nos. 10-11, pp. S69-JfJ,0; 12, pp. Jf50-.'f6',, figs. 5).— The author finds the virus of 

 this affection to be filterable, difficult to destroy by disinfectants, and resistant 

 to drying. It is destroyed at a temperature of 60° C. (140° F.). 



A campaign against dangerous poultry parasites, W. C. Thompson {Neto 

 Jersey Stas., Hints to Poultrymen, 8 {1920), No. 11, pp. 4). — This pamphlet calls 

 attention to the importance of certain parasitic insects and helminths as ene- 

 mies of poultry, and means for their control. Round worms, tape worms, gape 

 worms, lice, and mites are briefly considered. 



RURAL ENGINEERING. 



Agricultural engineering {Missouri Sta. Bui. 172 {1920), pp.13. Iff). — Inves- 

 tigations conducted by E. W. Lehmann, on the draft of a 6-shovel cultivator in 

 a variable sand and clay loam soil growing soy beans, showed that up grade on 

 clay loam soil the draft was about 470 lbs., about 400 lbs. up grade on sandy 

 loam soil, and 375 lbs. down grade on sandy loam. 



An investigation of sanitary conditions on 50 farms by B. W. Lehmann and 

 C. C. Taylor showed that of 4S samples of water taken from cisterns, springs, 

 and shallow wells, practically all were contaminated. 



Report of the hydrometric survey of British Columbia for climatic years 

 1916-17 and 1917-18, R. G. Swan {Canada Dept. Int., M'ater Power 

 Branch, Water Resources Paper No. 23 {1919), pp. 328, pi. 1, fig. i).— This 

 report presents the results of measurements of flow made on streams in the 

 Pacific coast, Fraser River, Thompson River, and Columbia River Basins, and 

 in miscellaneous smaller drainage basins during the climatic years 1916-17 

 and 1917-18. 



Spillways for reservoirs and canals, A. T. Mitchelson {U. S. Dept. Agr. 

 Bui. 831 {1920), pp. JfO, pis. 15, figs. IJ/). — This is a summary of information on 

 the subject, in which the author briefly points out the advantages of the 

 siphon spillway when it is desired to facilitate the escape of high flood crests, 

 and at the same time to conserve crest length and cost of construction and main- 

 tenance, by eliminating the use of mechanical or other energy necessary to op- 

 erate partially or completely automatic spillways of other types. It is stated 

 that the siphon is the only absolutely foolproof method of maintaining adequate 

 spillway capacity without the addition of moving parts. Data on design are 

 included. 



Tests of the over-all efficiency on working models of siphon spillways are 



described. It was found that the theoretical and actual loss of head in the 



various parts of the structure was not consistent for the various tests nor for 



the different models, but was of sufficient accuracy to warrant the use of stand- 



16032°— 20 7 



