Development of atmospheric cosmic-ray showers. II

In a recent paper Orford and Turver criticized one of our previous papers which had concluded that a change in cosmic-ray primary mass composition was required in the energy range ${10}^{15}$ to ${10}^{17}$ eV. It is suggested here, in reply, that the inconsistencies and shortcomings claimed by Orford and Turver are largely not substantiated in the light of available information and that, in the absence of new ideas, the original conclusions are valid.