Distribution of the energy in the extreme ultraviolet of the solar spectrum

Supplementing the data given in a previous publication (NBS R esearch Paper RP877), the present paper gives further calculations and graphs showing the distribution of energy in the extreme ultraviolet of the solar spectrum, for various air masses traversed by the rays, at a sea-level station (Washington); also the spectral-energy distribution of solar radiation outside the earth's atmosphere, showing that there is no similarity with the radiation of a black body at 6,000° li, which is sometimes used in calculating the ultraviolet solar spectral energy.The second part of the paper describes progress made in assembling apparatus for measuring the spectral q uality and total intensity of ultraviolet solar radiation by means of a photoelectric cell and filter radiometer transported aloft in sounding balloons.