On the influence of the nature of the cathode on the length of the crookes dark space

Abstract

In the work previously communicated by the author upon the subject of the cathode dark space only one metal, aluminium, was employed in the construction of the cathodes used. It therefore seemed desirable that cathodes of various metals, etc., should be experimented with in order to find out to what extent the relative values of length of dark space, pressure, current density, and voltage were affected by the material of the cathode. The cathode fall which is intimately connected with the ratio between current and voltage is certainly widely different for different metals so that it was thought very probable that the length of the dark space might also be affected. Preliminary experiments fully justified this expectation, and an apparatus was therefore designed for a systematic enquiry using cathodes of many different materials.