Transactions section: Preprint of corresponding pages from the current annual AIEE transactions volume

The development of the betatron, which accelerates electrons by magnetic induction making possible the production of higher energy X rays than is practical by the direct application of the accelerating potential, has extended the range of X rays indefinitely, the only limit being the size of the machine. Tests with the betatron have shown that the best energy for medical and radiographic use is 20 mev (million electron volts). The development of this machine from a physics laboratory instrument to an industrial machine is described, as well as the radiographic properties of the X rays produced.