The transmission of ultra-violet light through tracing cloth, by C. H. Young. Nature, London, 123, 1929, No. 3089, p. 47, fig. 1.

A brief communication announces that ordinary commercial tracing cloth transmits ultra-violet light to a surprising extent. The transmission is not affected to a marked degree by the thickness of the cloth and number of meshes to the centimeter. In angstrom units the limit of transmission was 2,535 for three samples of the cloth and 2,482 for two others, while the limit of various papers tested lay between 4,339 and 3,125.