Rocket observations of the Lyman &agr; and Lyman &bgr; day airglow are analyzed using a nonisothermal spherical model of the radiation field. This new model provides, for the first time, a method of determining atomic hydrogen densities in the mesosphere and thermosphere. Interpretation of Lyman &agr; data taken between 80 and 260 km is consistent with current mesospheric and thermospheric models, with H density equal to 1.9¿107 cm-3 at 100 km. Analysis of 1025A data suggests that the emission is dominated by Lyman &bgr; with perhaps as much as a 30% contribution from OI 1027.