Wolf Defries ( -1931)
1889 of J. Defries and Sons
1931 Obituary [1]
WOLF DEFRIES, M.B.E., was associated for most of his life with his father's firm, Messrs. Defries and Sons, London, best known in connexion with display illumination lighting. His experience covered a wide range of activities, which included the manufacture of glass-ware lamps for railway companies, "Safety" paraffin oil lamps, pneumatic safety lamps, various signal and telegraph instruments, and work in connexion with the Pasteur filter.
Mr. Defries was interested in bacteriological work, and the firm produced some ingenious indicators for the sterilization of bedding, etc., in hospitals. With thick mattresses which were usually treated in the sterilizing chamber in a tightly-coiled condition, it was difficult to know if the necessary sterilizing temperature had been reached in the centre of the mass. A series of lead-tin-bismuth alloys was prepared and drawn into wire about 1 mm. in diameter. By inserting short coils of these wires in glass tubes in the bundles, it was possible to ascertain the distribution and degree of temperature by the melting of the wires.
Mr. Defries served a five years' apprenticeship with Mr. V. I. Feeny of London, and by devoting his evenings to study he obtained the B.A. degree of the University of London. He was a skilled writer and linguist and was awarded the M.B.E. in connexion with editorial publications for the Ministry of Munitions during the War. He also contributed extensively to the technical engineering press.
Mr. Defries died on 24th December 1931, in his seventy-second year.
He had been a Member of the Institution since 1889.