On the reflection of electrons from crystal lattices

Davisson and Germer(1) have recently published their very interesting results on reflection of electrons from a single crystal of nickel. These results have been interpreted by analogy with the reflection of X-rays from crystals. This analogy, however, is not complete. The purpose of this short note is to point out the differences between the two phenomena. For the mathematical treatment use is made of the recent development of quantum mechanics (wave mechanics).