716 EXPEEIMENT STATION RECORD. 



to which the index slips were received by the Central Bureau too late for inclu- 

 sion iu the previous volumes. There are also entries dated 1912." 



"Weather and water, M. Hoffmann (Jahresher. Landw., 28 {1913), pp. 1- 

 20). — Recent investigations on these subjects are classified and reviewed as 

 u.sual. 



Influence of forest cover upon local climate (Quart. Jour. Roy. Met. Soc. 

 [Lonclon], 40 {19U), No. 110, pp. 166-168) .—ThiB is a brief review of a paper by 

 G. A. Pearson previously referred to (E. S. R., 30, p. 417). 



Influence of forest cover upon local climate, T. H. Moegan (Quart. Jour. 

 Roy. Met. 8oc. [London'], 40 (1914), No. Ill, p. 226).— This is a brief note on 

 the paper referred to above, calling attention especially to electrical differences 

 that may be set up in passing from open land to forest. 



The relation of forests in the Atlantic plain to the humidity of the Central 

 States and prairie region, R. ZoN (Proc. Soc. Amer. Foresters, 8 (1913), No. 2, 

 pp. 139-153, pis. 2) . — The author bases his conclusion that there is " a relation 

 between the forests of the coastal plain and the southern Appalachians, on the 

 one hand, and the humidity of the Central States and prairie region, on the 

 other," on three fundamental considerations presents data upon these, as 

 follows : 



"(1) In the eastern half of the United States there is a marked perodicity 

 in the wind direction. In winter the prevailing winds are from the north and 

 northwest; in summer they are from the south. When the prevailing winds 

 come from the south the entire eastern half of the United States is wet. When 

 the prevailing winds are from the northwest and west the precipitation de- 

 creases. Therefore, the precipitation of the eastern half of the United States 

 dei^ends largely upon the prevailing southerly winds which come from the Gulf 

 and penetrate far into the interior of the continent. 



"(2) The evaporation from the ocean plays a comparatively unimportant 

 part in the precipitation over the land; seven-ninths of the precipitation over 

 land is supplied by evaiwration over the land itself, and only two-ninths is fur- 

 nished by the evaporation from the ocean. Therefore, the greater the evapora- 

 tion from the land which is in the path of the prevailing southerly winds, the 

 more moisture must be carried by them into the interior of the continent. 



"(3) The forest evaporates more water than any vegetative cover and much 

 more than free water surfaces. Therefore, forests enrich with moisture the 

 winds that pass over them, and contribute to the humidity of the regions into 

 which the prevailing air currents pass." 



Restraining effect of forests on sudden melting of snow, J. E. Church, jb. 

 (Engin. Rec, 69 (1914), No. 24, p. 674). — Measurements are referred to which 

 indicated that the protection of snow against rain and sun is directly propor- 

 tionate to the density of the forest growth, and that the melting of snow is 

 most rapid in oiien ai'eas. 



A method of estimating rainfall by the growth of trees, A. E. Douglass 

 (Bui. Amer. Geogr. Soc., 46 (1914), ■^'o. 5, pp. 321-335, figs. 5).— The results of 

 studies of the rings of yellow pine trees near Flagstaff. Ariz., are correlated 

 with past meteorological conditions, especially rainfall. The curves for the 

 period of known rainfall show a close correlation with that for the tree growth. 

 A certain correlation between tree growth, as shown by the rings, and climatic 

 cycles is also indicated. 



Distribution of drought, F. Eredia (Internat. Inst. Agr. [Rome], Mo. Bill. 

 Agr. Intel, and Plant Diseases, 5 (1914), No. 3, pp. 325-329).— Following the 

 suggestion of Broounoff that a knowledge of the distribution of the rainfall of a 

 given region during 10-day periods may be used to advantage iu adapting crops 



