METEOROLOGY AND ALLIED SUBJECIS. 



2G3 



For equal thicknesses of the atmosphere penetrated by the rays the 

 radiation on liigh ii^untains is more intense than on the i)lains, con- 

 trary to what Forbes had deduced by his own observations ; hence, it 

 follows that the lower stratum of air acts with greater absorbing power 

 than the upper stratum, as is also explained by the greater mass of 

 aqueous vapors, as well as by the greater accumulation of dust in the 

 lower portions of the atmosphere. (Z. 0. O. 3L, XIV, p. 312.) 



Eeiset, as the mean of a number of observations during the years 

 1872-'79, comes to the conclusion that the air of the free atmosphere 

 contains on the average 0.02942 of one per cent, of volume of carbonic 

 acid gas. The extreme variations of his measures do not exceed 0.03. 

 {Z. 0. 6. M., XIV, p. 452.) 



Hasselbarth and Fittbogen, from observations in 1874 and 1875, con- 

 clude the following to be the volume of carbonic acid gas in the air : 



January 3. 26 



February 3. 22 



March . .' 3. 41 



April 3. 43 



May 3. 30 



June 3.31 



July 3. 31 



August 3. 40 



September 3.41 



October 3. 34 



November 3. 43 



December 3. 25 



The largest variations in the quantity of carbonic acid are apparently 

 due to the variations of the wind. An increase in the wind is followed 

 by a diminution of the carbonic acid. Eain usually causes a depression, 

 but after thunder storm an increase in the quantity is usually noticed. 

 {Z. 0. G. M., XIV, p. 452.) 



Schultze has observed the same property in Eostack, and the follow- 

 ing table shows the means of his observations : 



January 2. 90 



February 2. 90 



March 2. 99 



April 2.97 



May 2. 94 



June 2. 92 



July 2. 90 



August 2. 88 



September 2.90 



October 2. 95 



November 2. SO 



December 2. 84 



Year 



2.91 



{Z. 0. O. il/., XIV, p. 453.) 

 J. L. Schonn states that, having obtained a very i)erfect i)rism from 

 Hilger, in London, he examined water and other substances with refer- 

 ence to their transmission of heat. The proportion in which the ultra- 

 violet solar rays are absorbed by the va[)or of water in the atmosphere 

 cannot be preliminarily stated, because the ratio of the intensity of the 

 sun's light of that special kind to the light of the electric spark is un- 

 known, but it is still plain that the absorption of the ultra-violet is 

 (caused by the aqueous vapor. The behavior of ice is entirely ditlerent 

 from that of fluid water; with the thickest blocks of ice (six or eight 



