... shutter. This big disc with the slots in the edge is set up before the lens and run at such a speed that half a million slots per second pass before the lens. The film, which is sixteen millimeter X-ray film, travels behind the lens at a speed of nearly five miles per second. It has to be gradually worked up to this speed, and after the whole thing is set up, it takes it nearly four hours ... — Astounding Stories of Super-Science February 1930 • Various
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