History of Electrical Engineering – May 2008

By Bob Morrison

05 May, 2008

Scanning the Past: A History of Electrical Engineering from the Past
Submitted by Bob Morrison, Editor

William D. Coolidge and Ductile Tungsten
Eighty-five years ago this month, William D. Coolidge presented a significant paper concerning the discovery of a new method of producing ductile tungsten at a meeting of the American Institute of Electrical Engineers (AIEE). The breakthrough which he reported had been achieved by a research team led by Coolidge at the General Electric Research Laboratory in Schenectady, NY , and it was to have a major impact on production of electric lights, electronic tubes, and numerous other applications.

Coolidge was born in 1873 on a farm near Hudson, MA. He graduated in electrical engineering from the Massachusetts Institute of Technology (MIT) in 1896 and spent a year as a laboratory assistant at MIT. He then accepted a graduate fellowship for study in Germany where he earned the Ph.D. in physics from the University of Leipzig in 1899. He then returned to MIT where he worked as a laboratory assistant to Prof. Arthur A. Noyes and did some teaching until 1905, when he joined the General Electric Research Laboratory. He soon began what proved to be a very difficult quest for a way to produce ductile tungsten suitable for filaments in incandescent lamps. He became assistant director of the Research Laboratory in 1908, and two years later, reported the successful outcome of the ductile tungsten project.

In his May 1910 AIEE paper, Coolidge outlined the difficulties in producing ductile tungsten and how they had been overcome by a combination of reducing impurities and carefully controlled mechanical working. He stated that “the product which we now have is a perfectly pliable ductile wire, which has the strength of steel.” He mentioned that approximately 20 research chemists and a “large body of assistants” had contributed to the effort. Samples of ductile tungsten wire in various sizes were available for inspection by those who heard his paper. Commercial lamps using ductile tungsten came on the market in 1911 and soon became a major source of income to the General Electric Company. Coolidge was awarded a patent on the process in 1913 although it was held to be invalid by the courts some years later on the grounds that it did not constitute an invention in the sense required by patent law. He published a second AIEE paper on applications of metallic tungsten in 1912 and received the Rumford Medal of the American Academy of Arts and Sciences in 1914.

Coolidge also became known for his contributions to the development of improved X-ray tubes. The “Coolidge tube” introduced in 1913 enabled better control of X-ray intensity than previously possible. During the first World War, he helped develop portable X-ray apparatus for use by the military and also worked on a project for the sound detection of enemy submarines. He also made important contributions to the field of vacuum-tube electronics where ductile tungsten proved an important innovation, especially in high-power tubes.

Coolidge received the Edison Medal of the AlEE in 1928 in recognition of his many contributions to electrotechnology and also was awarded the Faraday Medal by the British Institution of Electrical Engineers in 1939. In 1932 he succeeded Willis Whitney as Director of the General Electric Research Laboratory and devoted most of his energy to being a research administrator for the rest of his career. He became a GE vice president in 1940. He retired in 1944 but continued to work as a consultant to GE and in 1946 was rehired for a few months to establish a laboratory in Richland, WA, for atomic research and development. A biography of Coolidge entitled Yankee Scientist by John A. Miller was published in 1963. Coolidge died in 1975 at the age of 101.

James E. Brittain
School of History , Technology and Society
Georgia Institute of Technology