On the Property of emitting "N" Rays, which is conferred on Certain Bodies by Compression, and on the Spontaneous and Indefinite Emission of "N" Rays by Hardened Steel, unannealed Glass, and other Bodies in a State of Strained Molecular Equilibrium (December 7, 1903).
Professor A. Charpentier kindly undertook to keep me informed with regard to the progress of certain researches of a physiological nature which he is conducting in connection with "N" rays, unpublished researches which (note 11) promise highly interesting results. These experiments led me to the idea of examining whether certain bodies did not acquire, by compression, the property of emitting "N" rays. For this purpose I compressed, by means of a carpenter's press, bits of wood, glass, rubber, etc., and I immediately observed that these bodies had in fact become, during the compression, sources of "N" rays; brought near a mass of phosphorescent calcium sulphide, they increased its luminosity; and they can also be
