Frederick Cottrell


Frederick Cottrell invented the "electrostatic precipitator," which removes pollutants from smoke. Cottrell was born on January 10, 1877, in Oakland, California, the son of Henry and Cynthia Cottrell. His ingenuity and interest in the applied sciences were demonstrated early on. At the age of thirteen, he ran his own printing business with a handpress in the basement of his home, publishing, among other works, a four-page technical magazine, Boy's Workshop. He also earned money from odd jobs as an electrician and landscape photographer.

After graduating from Oakland High School, Cottrell attended the University of California at Berkeley. He graduated at the age of nineteen in 1896 with a B.S. in chemistry. He taught high school chemistry for four years and then traveled to Germany, where he earned a doctorate in physical chemistry at the University of Leipzig in 1902. He returned to a teaching appointment at Berkeley, but resigned in 1906 to do independent research on industrial pollution.

A local form of air pollution, the acidic mists from the chimney of a nearby sulfuric acid factory, had triggered Cottrell's interest in this field. Recognizing that fine droplets and solid particles in smoke are held in suspension by the repulsion of electrical charges on their surfaces, Cottrell decided to build a device that could neutralize these charges. The result was a set of probes with a charge of opposite sign that neutralized the charges on the suspended material and caused it to precipitate. The first patent for the electrostatic precipitator was issued on August 11, 1908.

The precipitator was soon at work, removing the acid mist from the stack gases of the sulfuric acid plant. A modification of the original design then removed arsenic dust, as well as lead particles, from the emissions of a lead smelter. A further modification precipitated the dust from the emissions of a cement plant.

Cottrell had struggled to finance the experiments that led to the development of the electrostatic precipitator. Although the profits from the eventual manufacture of his precipitator could have made him a wealthy man, he decided that a portion of these monies should go to the support of scientific research. In 1912 he founded the Research Corporation, which is still the recipient of fees from the original patents and distributes them as research grants.

In 1911 Cottrell was appointed chief physical chemist at the U.S. Bureau of Mines, where he rose to the position of director in 1919. He joined the National Research Council (NRC) in 1921, and in 1922 became director of the Department of Agriculture's Fixed Nitrogen Laboratory. He retired in 1930 and devoted the remainder of his life to the Research Corporation. Cottrell died on November 16, 1948, while attending a scientific meeting in Berkeley, California.

Cottrell precipitators continue to benefit the environment by removing particulates from the gases routinely emitted by factory chimneys. Companies that install them find that the devices soon pay for themselves in terms of the value of the materials that are recovered from the precipitated solids.

The Research Corporation continues to benefit the advancement of science through its grants. The organization tends to favor young scientists in need of funds to support their first major projects. As Cottrell himself remarked, "Bet on the youngsters. They are long shots, but many will pay off" (Barker, p.17). Among the recipients of Research Corporation grants were Ernest Lawrence, who developed the cyclotron, for which he received a Nobel Prize in physics, and contributed to the development of atomic energy, and Robert Goddard, pioneer rocket scientist.

SEE ALSO Lawrence, Ernest .

Lyman R. Caswell


Barker, Joseph Warren (1952). Research Corporation (1912–1952): Dedicated to Progress in Education and Science. New York: Newcomen Society in North America.

Cameron, Frank T. (1952). Frederick Gardner Cottrell, Samaritan of Science. New York: Doubleday.

Daniels, Farrington (1949). "Frederick Gardner Cottrell: 1877–1948." Science 110 (11): 497–498.

Manchester, Harland (1948). "He Lives a Thousand Lives." Reader's Digest 52 (April): 113–116.

Internet Resources

Research Corporation. "Frederick Gardner Cottrell." Available from .

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