PROGRESS OF METEOROLOGY IN 1889. 231 



judging the relative diatbermaucy. {Meteorologische Zeitschrift, 1889, 

 VI, p. 62.) 



E. Ssawelief has made a series of solar radiation observations at 

 Kiew, extending througb 1888. Tbe instrument used was a Crova 

 actinometer. Tbe yearly range of tbe intensity of solar radiation at 

 Kiew agrees witb that at Montpellier. Tbe principal maximum, 1.39 

 calories, occurred on May 8; tbe principal minimum, 1.13 calories, at 

 tbe winter solstice (on account of tbe small altitude of tbe sun). Since 

 the values of tbe radiation are very nearly tbe same at Montpellier and 

 at Kiew, though the latter is 7 degrees farther north, it follows that in 

 Russia tbe air has a materially greater diathermancy. The variations 

 of the diathermancy at Kiew are smaller than at Montpellier. 



Tbe value of the solar constant is computed from a series of forty-two 

 measures, made on January 7, and found to be 2.86 calories. In obtain- 

 ing this result, the observations at midday were excluded because they 

 showed a smaller radiation than both beforeand after noon, resultingfrom 

 adiminished diathermancy. This large solar constant, which approaches 

 very nearly to Langley's values, shows again the extraordinary purity 

 of tbe air iu Russia on tine winter days. {Comptes Eendns, cviii, p. 287.) 



Actinometric observations made in 1888 at tbe Montpellier Observa- 

 tory are reported by M. A. Crova as confirming the results established 

 by ijrevious observations, namely, that a primary maximum of intensity 

 always occurs in spring and a secondary maximum in autumn. {Na- 

 ture, XXXIX, p. 504.) 



Dr. J. M. Peruter has discussed tbe solar radiation observations made 

 by Lephay at Cape Horn with a Pouillet pyr-heliometer, and despite tbe 

 fact that such a crude instrument was used, some valuable results are 

 derived. 



A selection of tbe best observations, tabulated a'jcordiug to the 

 zenith distance of the sun, shows that the diathermancy of the atmos- 

 phere increases materially with tbe zenith distance of tbe sun. Tbe 

 cause of this is attributed to the fact that rising air currents are most 

 frequent in summer and in the middle of the day, and that aqueous 

 vapor carried to great heights by these convecti ve currents is condensed 

 in the upper air strata even on clear days when the amount of condensa- 

 tion is not sufficient to be visible. The average summer value of the 

 midday diathermancy is 0.55; tbe average winter value is 0.80. {Me- 

 teorologisehe Zeitschri/t, 1889, vi, p. 130.) 



Atmospheric absorption. — Dr. Angstnhn has communicated to the 

 Royal Academy of Sciences at Stockholm a contribution on the absorp- 

 tion of radiant heat through the various components of the atmosphere. 



Distribution of heat over the earthls surface. — Dr. Zenker has made 

 an elaborate research on the distribution of heat over the earth's surface, 

 taking account not only of tbe radiation from the sun and absorption 

 of heat by the atmosphere, but also of the effect of the distribution of 



