614 EXPERIMENT STATION BECOED. 



due to the drainage of cold air to the low areas during the typical clear, calm, 

 frosty nights. . . . 



"The variation in the minimum temperatures of the high and the low por- 

 tion of a valley are reduced about 60 per cent during cloudy weather. The 

 clouds interfere with free movement of the cold air flowing to low areas. 

 During windy weather the low areas may exi>erience a slightly higher minimum 

 temperature than the bench land due to their protected positions. The wind 

 has a tendency, however, to equalize the temperature of the various areas in 

 a valley. 



" The variations in minimum temperatures experienced by the highlands 

 and lowlands of a mountain valley due to the drainage of cold air to the 

 bottoms is much the same throughout the year regardless of season. The varia- 

 tions in maximum temperatures experienced by different sections of a mountain 

 valley were only slight during the period under observation compareil with the 

 variations in minimum temperatures, and bore little or no relation to the 

 latter." 



The general conclusion is that " the success or failure of a fruit orchard in 

 the intermouutain States might depend entirely upon its location within a 

 given area of tillable land." 



Reforestation and occult condensation, P. Descombes, trans, by 11. Lvii-^N 

 and C. ^Vbbe, Jr. (Assoc. Franc. Avanc. Sci., Compt. Rend., 43 {191.'f), pp. 337- 

 341; r. .S'. J/o. ^yeathcr Rev., 43 (1915), No. 12, pp. 617. 6iS).— Observations by 

 other investigators are cited to show that in certain drainage basins the 

 quantity of water derived from condensation of water vapor ("occult condensa- 

 tion") exceeds that lost by evaporation, and it is maintained that the amount 

 so obtained is greatly decreased by the destruction of forests and other forms 

 of vegetation. 



Monthly Weather Review (U. S. Mo. Weather Rev., 43 (1915), Nos. 11, pp. 

 543-587, pis. 9, fi(js. 13; 12, pp. 5S9-650, pis. 10, figs. 7).— In addition to weather 

 forecasts, river and flood observations, and seismological reports for November 

 and December, 1915 ; lists of additions to the AVeather Bureau Library and of 

 recent papers on meteorology and seismologj- ; notes on the weather of the 

 months ; solar and sky radiation measurements at Washington, D. C, during 

 November and December, 191.j; condense<l climatological summaries; and the 

 usual climatological tables and charts, these numbers contain the following 

 articles : 



No. 11. — Increased Solar Activity and Atmospheric Optical Phenomena, by 

 J. Maurer; Aurora of June 16-17, 191.5, by D. F. Manning; Aurora of June 

 16-17, 1915, at Ashland, Ohio, by S. W. Brandt; Study of the Upper Air by 

 Means of Telescoix\s; Working Up of Wind Observations (illus.), by J. W. 

 Sandstrom ; Waterspouts Observed off Cape San Lucas (illus.). by W. J. Fisher; 

 Circulation and Temperature of the Atmosphere, by W. H. Dines; Forecasting 

 Thunderstorms, by G. Guilbert, with Comments by Durant-Greville (illus.) ; 

 A Breathing Well, by J. Free; A Temperature Inversion in the Grand River 

 Valley, Colo, (illus.), by E. S. Nichols; Relation between Meteorological Condi- 

 tions in the Netherlands and Some Circumjacent Places, by J. P. van der Stok; 

 Internal Structure of the Earth and the Moon, by H. Jeffreys ; Snow Survey on 

 Cottonwood Creek, Idaho, by A. J. Henry ; and Tornado at Pace, Fla., Novem- 

 ber 26, 1915. 



No. 12. — Solar Radiation Intensities at Santa Fe, N. Mex., during September, 

 November, and December, 191.5, by H. H. Kimball ; A Halo in the JIaking, 

 by J. R. Weeks ; Lunar Halo of June 24-25, 191.5, at Richmond. Va.. by T. R. 

 Brooks et al. ; The Penetrating Radiation Present in the Atmosphere, liy 

 A. Gockel ; Concomitant Changes in Terrestrial Magnetism and Solar Radiation, 



