I'':i01 METEOROLOGY. 117 



fi-itin 40 to no por cpiit niorp stiiisliinp th:in oociirs alonff the central and east 

 Ciuir coast. The njaxiniuui suiiiiiicr amount for the coiuitry as a whoh' is 

 experience<l in the Great Valley (if Califcirnia and over the western portion of 

 the plateau region. The interior of California has ahnost continuous cloudless 

 skies during the summer months. . . . 



" In autumn, especially during October and November, much cloudy weather 

 is ex[ierit"nccd in the region of the Great Lakes, the upper Ohio Valley, and the 

 far Northwest, where in .some places the average daily amount in November is 

 less than 2 hours, but at the same time the daily averages in portions of the 

 Southwest are in excess of hours. In the fall, there is a uniform and rather 

 marked increase in the amount of sunshine from the northeastern to the 

 southwestern portions of the country. In interior districts the averages for 

 this seas(»n are mostly 7 or S hours daily. . . . 



"In general, the amount of sunshine is less during the e.iily Miorniiig hours, 

 with a secondary miuinnun in the late aflenioon. Tiio grcnti'Sl :iiiiouiit occur-; 

 near midday." 



On oliservations of solar and sky radiations and tln'ir importance to 

 climatology and biology and also to geophysics and astronomy, < '. Doiino 

 ( r. S. Mn. Wcatlirr Rev., J,8 (J!)20), No. 1, pp. i<S-2//).— This is a trausl.ition 

 of a paper sunnnarizing the present knowledge on the subject. 



It is shown that the solar cimstant is one of the most important in nature, 

 since upon it depends all organic life, and that no other climatic element 

 viiries so greatly from place to place or from season to season in calorific, 

 luminous, chemical, and bactericidal properties. "The solar radiation is by 

 no means always similarly composed; the low sun is much richer in loug- 

 wave<l radiations (nm<h rediler) than the high sun, as everyone knows from 

 experience. Also with the same elevation of the sun there exists a pronounce<l 

 yearly march. The spring sunlight is — at lea.st on the Alpine heights — nuich 

 richer in beat rays, that of autumn much richer in the ultra-violet ones. The 

 difference between sunlight and shadow light increases in marked degree with 

 elevation of the sun and still more so with the color of the light, .since the 

 sky, as appearance teaches, is nnicli richer in short-wave (blue) light than the 

 sun with its long-wave rays (infra-red, red, and yellow). With middle sun 

 elevations and cloudless sky, the rtnl light of the sun falling on the horizontal 

 surface is fcmnd to be 14 times stronger than that from the sky, while its 

 brightness is only 11 times stronger, its chemical rays only 4.4 times, its pure 

 ultra-vi<»let (bactericidal) rays even less strong than those of the sky (oidy 

 about half so powerful)." ^ 



Tlie sun as a source of power (U. »9. Mo. Weather Rev., J/S (Jf>20), Xo. /, 

 p. /7). — Various theories and proposals relating to the utilizaticm of the sun's 

 energy are briefly discussed, and it is stated that " in view of the declining 

 natural resources of the world, the increasing studies in solar activity, and 

 the application of electrical methods and devices, it is not idle to hope for an 

 eflicient and practical method of converting the sun's heat into usable com- 

 mercial power." 



How rainfall data may be used for determining road conditions, T. G. 

 Shipman (U. S. Mo. Weather Rev., 48 iW20), No. 1, p. S3; abs. in Bui. Amer. 

 Met. Soc, 1 (1920), No. 3, p. 35). — This article notes briefly the results of an 

 attempt to determine the effects of rainfall on highways so that telegraphic 

 reports of rainfall can be utilized in making up the daily highway weather 

 service bulletin of the U. S. Weather l',ureau. It is based upon replies to a 

 questionnaire regarding the condition of dirt roads in Arkansas, mainly luider 

 sprhig, late autumn, and early winter conditions. The general conclusion is 



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