234: W. Hallock — Very on Atmospheric Radiation. 



which is very nearly a maximum for this temperature, further 

 increase of the radiant depth being unattended by a correspond- 

 ing addition of radiant energy, showing that equilibrium between 

 radiation and emission has been almost reached at this depth ; 

 the radiation from a layer of steam five feet deep at one-sixth of 

 atmospheric pressure is two and one-half times that from a like 

 body of dry air at temperatures near the boiling point of water, 

 and eight-tenths of the radiant emission from the black solid 

 body ; while for smaller depths the radiant power of water vapor 

 is relatively greater." (P. 129.) 



The accompanying diagrams, figs. 3 and 4, are reproduced 

 from the summary. Fig. 3 is a provisional energy-curve of the 

 radiation of moist air for the temperature +50° C. The positions 

 of the bands (from observations by Paschen, Rubens and Asch- 

 kinass) relate to the emission from aqueous vapor and carbon 

 dioxide with the exception of those of extreme wave length 

 provisionally assigned to nitrogen, oxygen, etc., from observa- 

 tions by Hutchins of the absorption of air radiation by quartz. 

 Fig. 4, the curve of transmission of radiation by the terrestrial 

 atmosphere, relates to a vertical transmission through a clear air 

 of moderate humidity, and shows the general fact of selective 

 absorption scattering of short waves with the progressive strength- 

 ening of band absorption in the infra-red, due to the gases indi- 

 cated (mainly water vapor), to finally a region of almost total 

 absorption provisionally attributed to the permanent gases of the 

 atmosphere. 



In conclusion, it may not be amiss to call attention to the 

 important bearing which recent investigations on electrification 

 of gases, and their electrical behavior under the influence of 

 violet, ultra-violet, Becquerel and X-rays, is sure to have upon 

 the problems involved in meteorology. 



Columbia University, Physical Laboratory. 



