From the August 16, 1930, issue

MILLION VOLT GLOBE

The shiny metal globe which the front cover pictures was spun on a lathe from two flat sheets of copper one-eighth inch thick. It will be used with another by the Westinghouse Electric and Manufacturing Company to measure man-made lighting of 2,000,000 volts and greater.

When high potentials are measured by sphere spark gaps, the distance between the spheres must not be greater than their diameters if the measurements are to be accurate, it has been found.