Abstract
The intensity of the net outward flow of energy by radiation from the earth to the atmosphere was measured and compared with the theoretical result. The thermopile, which was used, was calibrated with the infra-red standard radiation from the surface of water of various temperatures from 0°C to 5°C. Several infra-red filters were used in order to cut off the intervening effect caused by the scattered short wave-length radiation from the sky and to investigate the spectroscopic distribution of the atmospheric radiation. These filters are composed of nitro-cellulose films of 2 or 3μ thickness on which powders of MgO, ZnO, NH4Cl and quartz are deposited. These powders scatter the short wave-length radiation and pass the infra-red ray. Besides some of them show characteristic absorptions in the wave-length region of 7 to 9μ.
