base films vapour-quenched onto glass substrates. A similar technique has already been used for producing Al-type overlays of S, Ge, Sn, Se and Te. On annealing cyclically at increasing temperatures, a critical temperature is reached at which the overlay breaks because of the transformation of the Al-type modification to the usual crystal structure. Both the density and the superconducting transition temperature of the overlay depend on the base-film material and increase, for each element, with decreasing base-film lattice constant. The density is larger than the ordinary, but smaller than would be expected for a perfect pseudomorph or an ideal close-packed atom arrangement. The superconducting transition temperature is higher the thinner the overlay and the lower the annealing temperature. A comparison with previous results shows that the superconducting transition temperature of the Al-type overlays is higher than both that of films with normal crystal1 structure quench-condensed directly on glass substrates and that of samples subjected to high pressures. (Italy) CRcaIe, Vacuum, 27 (l), 1977,3-6. 3 1. SPUTTERING 3340. The roughness parameters of glass films. (GB) 21