19201 RURAL ENGINEERING. 887 



infected turkeys. The demonstration of the uniform susceptibility of the 

 normal turkey throughout its period of growth not only opens the way for 

 further investigation of the question of transmission, but also serves as a basis 

 for future work on other problems relating to the virus of blackhead." 



The value of comniercial vaccines and bacterins against fowl cholera, 

 L. Van Es and H. M. Martin (Nebrofika Sta. Research Bui. 18 {1920), pp. 

 3-11). — This is the report of a study, conducted along similar lines to the one 

 noted on page S82, of fonnnercial vaccines and bacterins against fowl cholera. 

 The preparations, purchased from six different manufacturers, included '' Hemor- 

 rhagic Septicemia Vaccine (Avian)." " Hemorrhagic Septicemia Combined 

 Bacterin (Avian)," "Avian Hemorrhagic Septicemia Bacterin," "Avisepticus 

 Bacterin," "Hemorrhagic Septicema Vaccine (for fowls)," and "Fowl Cholera 

 Bacterin." Several fowls were treated with each of these preparations and 

 subsequently tested for immunity by means of inoculations with fowl cholera 

 organisms secured from field outbreaks and cultivated in the laboratory. 



Of 100 chickens, the immunity of which was tested after from one to three 

 injections of the bacterin or vaccine, one only survived the immunity test. It 

 Is concluded that no reliance can be placed on these commercial vaccines and 

 bacterins against fowl cholera. 



Rabbit and cat diseases, C. G. Saunders (Chicago: Amer. Vet. Pub. Co., 

 1920. pp. 121). — The first part of this work deals with the diseases of rabbits 

 (pp. 1-G4). The second part deals with diseases of the cat (pp. 65-121). 



RURAL ENGINEERING. 



Topographic maps and sketch mapping, J. K. Finch {Nexv York: John 

 Wiley d Sons. Inc., 1920, pp. XI +175, pis. 4, figs. 7S).— This is a manual of in- 

 struction on topographic and sketch mapping. Part 1 deals with map reading, 

 part 2 with sketch mapping, and part 3 with landscape sketching. An appendix 

 contains a descriptive list of the principal topographic maps of the world, by 

 F. K. Morris, suggestions for a course in map reading and sketch mapping, and 

 a bibliography. 



Dredging engineering, F. L. Simon {New York and London: McGraw-Hill 

 Book Co., Inc., 1920, pp. X+182, pi. 1, figs. 56). — It is the purpose of this book 

 first to describe the principal types of dredges in such a manner as to impart a 

 fundamental working knowledge of their construction and operation, and then 

 to consider in concise fonn the u.sual problems confronting the engineer in the 

 conception and accomplishment of dredging projects. The following chapters 

 are included : Definition and classification, grapple dredges, dippei- dredges, 

 ladder dredges, scows, hydraulic dredges of the river type, hydraulic dredges 

 of the seagoing hopper type, objects and phases of the subject, preliminary engi- 

 neering, preliminary construction, operating, and removal of subaqueous rock. 



A study of the Venturi flume as a measuring device in open channels, 

 P. S. Wilson and C. A. Wright {Engin. Xetvs-Rec., 85 {1920), No. 10, pp. J,52- 

 457, figs. 6). — Experiments with two different designs of rectangular Venturi 

 flumes, conducted at Cornell University, are reported. Each Hume had a throat 

 width of 8 in., eciual to one-third the width of the channel, and each converged 

 in a distance of 3 throat widths and diverged in a distance of 10 throat widths. 

 One had a throat length equal to 3 throat widths and the other a throat length 

 equal to 1 throat width. 



It was found that the coefficient of the Venturi flume for any particular con- 

 dition of flow within rather wide limits is a fixed determinable quantity close 

 to unity. With the flumes experimented upon, however, the value of the coeffi- 

 cient varied over a range of possibly 10 per cent with varied conditions of flow, 

 piost of this variation being apparently due to surface phenomena, waves, etc.. 



