1916] METEOROLOGY. 15 



rainfall of May and June in North Dakota, 1.7 times the rainfall of these 

 months in South Dakota, about the same as the inches of rainfall during Jan- 

 uary, February, March, and April in California, four times the inches of rain- 

 fall during these months in Washington, and less than twice the inches of 

 rainfall of March, April, and May in Kansas and Nebraska, 



In regions of ordinarily abundant (as compared with regions of deficient) 

 rainfall, like Minnesota, Ohio, Indiana, Illinois, and Missouri, there was found 

 to be no direct relation between wheat yield and average rainfall. " The re- 

 sults in all cases indicate, however, that the best crops can be expected when 

 the rainfall is below the normal amount during the critical months of the 

 growing season." It was found that " in average years, the yield of corn 

 throughout the corn belt was approximately eight times the July rainfall. In 

 the best years, however, the yield was only seven times the rainfall for this 

 month, and in the poorest years it was ten times as great." 



Correlations are made of the approximate money value of different amounts 

 of rainfall to each crop in the area of deficient rainfall. 



Protection from, damage by frost, W. G. Reed (Geogr. Rev., 1 {1916), No. 

 2, pp. 110-122, figs. 8). — Conditions of frost occurrence, frost damage, methods 

 of protection, and frost forecasting are briefly discussed. The conclusion is 

 reached that the low temperatures resulting in frost injury " can be prevented 

 by heating the lower air to supply the loss of heat to the cold earth and by 

 checking radiation from the earth ; mixing the air is not now practicable. 

 The methods most successful commercially depend upon the combination of 

 heat and smoke. The best practice is fairly clean-burning small fires, one to 

 each one or two trees." 



Relation of the soil to meterological factors, E. G. Loske (Trudy Selsk. 

 Khoz. Met., Nos. 8 (1911), pp. XII-\-104; 9 (1912), pp. XIV+105-3S4; 11 

 (1915), pp. XVII+335-S00). — The literature of investigations bearing on the 

 subject is exhaustively reviewed and digested. 



Aridity and humidity maps of the United States, M. Jefferson (Oeogr. 

 Rev., 1 (1916), No. 3, pp. 203-208, figs. 2). — Two maps are described in which 

 an attempt has been made to represent simply and clearly the essential facts 

 of rainfall " that condition life in the United States." 



Agricultural meteorology in Canada, R. W. Mills (Agr. Gaz. Canada, 8 

 (1916), No. 2, pp. 171f-179). — This article briefly explains the purpose and plan 

 of the work of the department of agricultural meteorology of the Meteorological 

 Service of Canada, which was organized in 1914 to study the relation <tf meteoro- 

 logical conditions to crop growths by methods similar to those employed in 

 Russia. 



It is stated that 14 stations well distributed over Canada were in operation 

 in 1915 for the purpose of studying the relation of meteorological factors to 

 the growth of spring wheat. The plan followed called for the collection of 

 information regarding " (1) general field conditions and the farming methods 

 employed, (2) dates of the important stages in the life of the wheat, from sow- 

 ing to reaping, and the general condition of the plants at the time of the stages, 

 (3) average height of plants on the plat every seven days, (4) the damaging 

 effect of adverse weather phenomena on plants and soil, at any time through- 

 out the season, losses due to meteorological and to other factors, and (5) final 

 yield and quality." By means of a grapliical method the crop notes are com- 

 pai-ed with charts showing the daily temperature, precipitation, and bright 

 sunshine at each station throughout the growing season. 



[Report of the] committee for the investigation of atmospheric pollution 

 (Lancet [LmidoM, No 9 (1916), I, Sup., pp. I-XL, figs. 18).— This is the first 

 report of the committee and covers the investigations from April, 1914, to 



