In a recent article1 it was asserted that greater transparency and, as a result, better skiagraphs, can be obtained in x-ray work by having two sources of the rays at right angles to each other, radiating simultaneously on the body to be photographed. In order to test the truth of this assertion by the electroscope method the following experiments were undertaken:
Two x-ray bulbs, one which will be called the direct bulb D and the other the transverse bulb T, were arranged as indicated in the diagram, both being carefully enclosed in lead screens. Openings in the screens were made at a, b, c and d, through which the rays could pass and produce ionization in the three electroscopes, E,1 E2 and E.3 These electroscopes were protected in such a way that they were unaffected by the radiation from the bulbs when the openings a, b, c and d were