RURAL ENGINEERING. 387 



Some tests on strength of overwet concrete {Engin. Neivs, 11 (1914), ^o. 11, 

 pp. 587, 588, fig. 1). — Data and curves of tests show the effect of variation in 

 water content in concrete and the deleterious effect of using too much water. 



Use of hydrated lime in concrete pavements, R. S. Edwards (West. Engin., 

 .', (1014), No. 3, pp. 209-215; Nat. Lime Manfrs. Assoc. Bui. 1 (1914), PP- 12).— 

 The author points out that small percentages of hydrated lime when added to 

 concrete mixtures in road work will render the concrete highly plastic and 

 homogeneous, thus producing density and uniformity in the finished conci'ete, 

 will keep a certain amount of excess moisture in the concrete while setting, 

 will render the concrete mass more nearly watertight, thereby preventing 

 alternate wetting and drying of the finished concrete, and will reduce the 

 labor of spreading and finishing. 



Exterior plastering specifications (Cement and Engin. News, 26 (1914), 

 No. 3, pp. 10-13, figs. 5). — These specifications include materials, preparation of 

 mortar, structure, mortar coats, finish, and overcoating. 



Modern practice in heating and ventilation, XIV, A. G. King (Dom. Engin., 

 66 (1014), No. 11, pp. 228-331, figs. iO).— Special fittings and devices for hot 

 water circulation in domestic heating are described and suggestions given for 

 their installation. 



Handbook on sanitation, G. M. Peice (New York, 1918, S. ed., reivritten, 

 pp. 353, figs. 25; rev. in Set. Amer., 110 (1914), No. 10, p. 212). — The first part 

 of this book covers soil and sites, air, ventilation, heating, water supply, sewage 

 disposal, and plumbing. The second part is devoted to sanitary practice and 

 deals with the problems of housing, of trades and occupations, and of disin- 

 fection. The third part relates to sanitary inspection as a profession and 

 includes calculations and tables. 



The new public health, II. W. Hill (Minneapolis, Minn., 1913, pp. VI +128; 

 rev. in Engin. Neics, 11 (1014), No. 12, p. 646). — Public health as here con- 

 sidered relates almost wholly to communicable or infectious diseases. It is the 

 aim to control these at the source, which is the infected person, by measures 

 which will prevent infective material from escaping to other people. Among 

 other topics, the author discusses under the general heading of "community 

 defense," the public-health engineer, laboratory, and statistician. 



Hygiene of rural, suburban, and summer homes (Bd. Health Maine Circ. 

 100. pp. 44, fiffs. 23). — This paper i)oints out the essentials in the structure, 

 arrangements, and surrounding of homes to insure their healthfulness, par- 

 ticularly referring to the requirements of farm and suburban houses and 

 summer homes in the State of Maine. The discussion includes such topics as 

 location for the home, relative position of the house and other buildings, rela- 

 tive arrangement of rooms, warming of houses, food supply, water supply, dis- 

 posal of wastes, water carriage systems, and the typhoid fly. 



A rapid method of determining the probability of decomposition occur- 

 ring in a sewage effluent, E. S. Stokes (Rpt. Austral. Assoc. Adv. Sci., 13 

 (1011), pp. 619-688). — The author describes tests, gives data of results, and 

 concludes " that a very fair idea may be obtained as to the probability of de- 

 composition occurring in a sewage effluent by calculating the ratio between the 

 oxygen absorbed and the oxygen in nitrites and nitrates." This ratio he states 

 can be worked out by the following formula: Decomposition factor=N (as 

 N:03) X1.71+N (as NsOs) X2.S6^oxygen absorbed in 4 hours. For a satisfac- 

 tory effluent it is thought that this factor should exceed 0.7. 



Lighting of medium sized and small towns and rural communities, H. 

 Strache and F. Eisler (Bclcuclitnng mittlerer und kleiner Stddte un4 Ort- 

 schaften. Technische Praxis, Vienna and Leipsic, 1913, pp. 234, fiffs. 23; rev. in 

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