William D. Coolidge (nonfiction)

William David Coolidge.

William David Coolidge (23 October 1873 – 3 February 1975) was an American physicist and engineer, who made major contributions to X-ray machines. He was the director of the General Electric Research Laboratory and a vice-president of the corporation. He was also famous for the development of "ductile tungsten", which is important for the incandescent light bulb.