IN papers on secondary Rontgen radiation and polarised Rontgen radiation I have shown that all the phenomena of secondary radiation (as indicated by an electroscope placed several centimetres from the radiator) may, from substances of low atomic weight, be accounted for by considering the corpuscles or electrons constituting the atoms, to be accelerated in the direction of electric displacement in each primary Rontgen pulse as it passes through such substances, and that the interaction between the corpuscles affects only to a small extent the character of the secondary radiation proceeding from the substance. In light atoms there is almost complete independence of motion of the corpuscles within the limits of disturbance produced by all primary beams experimented upon.