Gas permeation through a joint of a vacuum chamber sealed with a filmshaped organic adhesive " M - f i l m " Hiroaki Okamoto, BS, is a senior research scientist at the Toshiba Central Research Laboratory, where his work has included both materials science and electronics. He has been employed there since 1939. The following papers by him have been published in English: Adsorption of water vapour on glass and other materials in vacuum. High temperature reactions of silica-glass with metals in vacuum. Gas analysis with a molecular sieve. His main interests at present lie in thin-film technology. Yoshio Murakami, BS, is a graduate in physics of the Tokyo Institute of Technology. Since 1960 he has been employed at Central Research Laboratory, Tokyo Shibaura Electric Co, Ltd. At present he is working on the application of gas adsorption and gas permeation phenomena in relation to vacuum technology.