618 EXPERIMENT STATION RECOHD. tVol. 4;^ 



diiced, and a process of generating alcohol from calcium carbid. Tlie last 

 name<l consists of decomposing the carbid with water, forming acetylene. Thin 

 is introduced into a heated diluted acid in the presence of a mercury compound, 

 forming acetaldehyde. This in turn, by a process of hydrogenation with 

 metallic nickel, is converted into alcohol. 



The economic values to Germany of the different processes are also discussed. 



METEOROLOGY. 



The blue sky and the optical properties of air, Lord Rayi.eigh {Nature 

 [Lo7idon], 105 (1920), No. 26'i5, pp. o8Jt-5S8).—Thn author concludes from 

 visual examination with a Nicol's prism and by means of photography that the 

 polarization of the daylight sky was almost complete, due to scattering of the 

 light by small particles in the air. Observation with a Savart polariscope did 

 not show a like polarization of the night sky, indicating a different origin of 

 the night light. Ozone appeared to have no relation to the blue color of the 

 sky. Experiments are reported which led to the conclusion that there is high 

 up in the atmosphere an absorbent layer of ozone that " acts as a screen to pro- 

 tect us from the ultra-violet rays of the sun, which without such a protection 

 would probably be fatal to our eyesight." 



The aeroplane and hail, G.-M. Stanoi^vitch {Compt. Rend. Acad. Sd. 

 [Paris], no {1920), No. 26, pp. 1590-1592; ubs. in Rev. Sci. [Paris], 5S {1920), 

 No. 13, p. 4^4)- — l^be author proposes the use of aeroplanes to upset atmospheric 

 conditions favorable to hail, on the theory that the motion of the propellers is 

 sufficient to destroy the characteristic calm which precedes the fall of hail. 



California precipitation, A. H. Palmek Jour. Electricity, 44 {1920), No. 12, 

 pp. G07-610; 45 {1920), No. 1, pp. 25-21, figs. 5).— This article, by the local rep- 

 resentative of the U. S. Weather Bureau, summarizes and discusses the avail- 

 able data of precipitation in California, but deals particularly with the snow- 

 fall in the mountains and its relation to the flow of streams, with special 

 reference to estimating its value for hydroelectric power and irrigation. The 

 available data for snowfall and run-off are summarized in tables and diagrams. 



A marked deficiency of run-off during the present season, 1919-20, as the 

 cumulative effect of four consecutive seasons of deficient precipitation was 

 noted, indicating that central California faced a serious shortage of water 

 during the summer of 1920. Timely warnings were therefore given to the 

 agricultural interests to plant only such crops as require a minimum of irri- 

 gation water, and the utmost conservation of water was urged until the next 

 rainy season. As a result the acreage of rice especially was reduced. 



The climate [of South Dakota], S. S. Visukk {is. Dak. Geol. and Nat. Hist. 

 Survey Bui. 8 {1918), pp. 50-67, figs. 7). — This article summarizes briefly the 

 more important available data regarding the general characteristics of the 

 climate of the State and the factors determining it, winds, temperature, length 

 of day, humidity, evaporation, cloudiness, precipitation, variability of the 

 weather, and supposed changes of climate. 



" The climate is invigorating. Clear skies and stimulating breezes prevail. 

 Though great ranges of temperature occur, the dryness of the atmosphere helps 

 to keep the sensible temperatures more nearly uniform. The summer season 

 is usually long and warm enough for raising corn. The normal annual pre- 

 cipitation is suQicient for the crops grown. The seasonal distribution of pre- 

 cipitation is very favorable, since slightly more than three-quarters normally 

 fall during the six months, April-October 1. The autumns and winters have 

 relatively little precipitation, to which fact is due the naturally-cured hay fur- 



