I 



1920] RURAL ENGINEERING. 189 



account of tho (loinand for plans and siKvifications and its hi'^di desree of 

 efHcicncy when used Tor small Hocks of layinj: l)irds. 



A Iiovor for the brooder stove, O. K. Siioup {Washi)}ffti)n Sia., llV.sV. irrj.s7(. 

 Stti. J/o. JiuL, S (1920), No. 1, pp. 10-1. 't, fifj. 1).—A hover to be used in connec- 

 tion with a brooder stove for broodins; chickens is described and illustrated. 

 II is stated that a hover 96 in. in diameter is required to properly acconnnodate 

 l.OOO cliickens when five weeks old. A table is given showing the approximate 

 size of hover required for various sized flocks of chickens from a day old up 

 to four or five weeks old, based on an estimate of 40 chickens per square foot 

 when first hatched and 20 chickens per square foot when four to live weeks old. 



Screen wire cloth durability tests, J. W. Scott (M'yomiiKj »S7r/. Rpt. 1919, 

 p. 151). — A progress report of screen wire cloth tests, conducted in cooperation 

 with the P>ureau of Entomolog.v of the U. S. Department of Agriculture, states 

 that after two years all panels of wire are still intact, and that all grades of 

 wire tested give good sei'vice in the Wyoming climate. To prevent serious 

 weathering, screen wire sliould be painted when first put xip and as often as 

 once a year afterward. 



Studies on the treatment and disposal of industrial wastes. — III, The 

 ])iirification of tannery wastes, H. B. Hommon (Pub. Health ticrv. V. 8., Pub. 

 Jlealth Bui. 100 (1919), pp. 133, pis. 3). — Experiments on the purification* and 

 disposal of tannery wastes as conducted by the U. S. Public Health Service 

 are described in considerable detail, and conclusions and re^mnicndations 

 presented. 



The process of treatment recommended includes utilization of the dried sludge 

 as a fertilizer. " Direct utilization of the liquid sludge to fertilize nearby land 

 by means of tank w^agons may be found more economical than the use of drying 

 beds xinder certain conditions." 



Studies of methods for the treatment and disposal of sewage. — The 

 treatment of sewag;e from single houses and small communities, L. C. 

 Frank and C. P. Riiynus (Pub. Uealth Serv. U. N., Pub. Health Bui. 101 (1919), 

 pp. in, pis. 13, figs. 12). — Several years' experiments conducted by the U. S. 

 Public Health Service on residential and small community sewage purilication 

 and disposal are reported, covering the use of settling, septic, biolytic, and Im- 

 hoff tanks, and oxidation methods, such as broad and subsurface irrigation, 

 intermittent sand filtration, treatment on contact beds, use of trickling filters, 

 and the activated sludge method. 



It was found that among the tank treatments for the removal of suspended 

 solids plain settling tank treatment is not well adapted for iise in snuill plants 

 because of the necessity of frequent cleaning. Septic-tank treatment is adapted 

 to use in small-plant conditions only in cases where the foul odors from the 

 effluent will not have access to the outside air, or where the plant is sufficiently 

 renioved from habitations so that such access is unimportant. A short test 

 also indicated that the biolytic tank is adapted for use in small plants under 

 the conditions outlined for the septic tanks. The IndiolT tank is adapted to 

 the conditions of very small and moderate-sized plants. Essential elements of 

 design are a mean detention period of not less than 4.5 hours and sludge and 

 scum chamber capacities of not less than 3.5 and 2.5 cu. ft. per capita, re- 

 spectively. 



Among the various oxidation methods, broad irrigation is not adapted to 

 small-plant conditions. Under certain conditions, subsurface irrigation is well 

 adapted to household and small community use. " Th(» conditions under which 

 this system may be relied upon, however, jire not readily di-tinable, nor can 

 the actual local conditions be determined by superlicial study. The system 



