394 1937 C.J. DAVISSON tron diffraction and verified de Broglie's formula at the same time as we in New York. And to mention, as closely related to the subject of this discourse, the difficult and beautifully executed experiments by which Stern and Ester mann in 1929 showed that atomichy drogen also is diffracted in accordance with the de broglie-Schrodinger theory Important and timely as was the discovery of electron diffraction in inspir ing confidence in the physical reality of material waves, our confidence in this regard would hardly be less today, one imagines, were diffraction yet to be discovered, so great has been the success of the mechanics built upon the conception of such waves in clarifying the phenomena of atomic and sub atomic physics394 1937 C.J.DAVISSO N tron diffraction and verified de Broglie’s formula at the same time as we in New York. And to mention, as closely related to the subject of this discourse, the difficult and beautifully executed experiments by which Stern and Ester￾mann in 1929 showed that atomichy drogen also is diffracted in accordance with the de Broglie-Schrödinger theory. Important and timely as was the discovery of electron diffraction in inspir￾ing confidence in the physical reality of material waves, our confidence in this regard would hardly be less today, one imagines, were diffraction yet to be discovered, so great has been the success of the mechanics built upon the conception of such waves in clarifying the phenomena of atomic and sub￾atomic physics