Secondary Electrons of High Velocity From Metals Bombarded with Cathode Rays

The magnetic spectra of high-speed secondary electrons emitted by Au, Ag, and Al, when bombarded with cathode rays of from 16 to 40 kv., have been photographed and densitometered. Beginning at the high-velocity end, the density is zero down to energy $e{V}_0$ equal to that of a primary ray, then rises rapidly to a maximum at about $0.94e{V}_0$ for Au or Ag, or $0.85e{V}_0$ for Al, and then declines. The density is everywhere continuous. Its first derivative may be discontinuous at $e{V}_0$ but nowhere else.