A thin film of beryllium evaporated in an electron diffraction camera, at liquid-helium temperatures, was examined as to its structure and for superconductivity - the former by reflexion diffraction, the latter by the `electron shadow' method. It was found (i) that the film was superconducting below about 7 °K (ii) that the structure was `amorphous'. The same film after annealing at room temperature gave the normal hexagonal diffraction pattern; in this state it was not superconducting at the lowest temperature used (4·2 °K).