Blodgett, Katharine Burr (1898–1979)

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Blodgett, Katharine Burr (1898–1979)

American physicist who became the first woman research scientist hired by General Electric laboratories and the first woman to earn a Ph.D. in physics from Cambridge University, best known for her invention of non-reflecting glass. Pronunciation: BLAH-jet. Born Katharine Burr Blodgett on January 10, 1898, in Schenectady, New York; died on October 12, 1979, in Schenectady; daughter of George Bedington (a patent attorney) and Katharine Buchanan (Burr) Blodgett; graduated Bryn Mawr, A.B., 1917, University of Chicago, M.S., 1918, Cambridge University, Ph.D., 1926; never married; no children.

Hired by General Electric Research Laboratories, Schenectady, New York (1918); developed color gauge to measure extremely thin films (1933); invented nonreflecting glass (1938); devised smokescreen for Allied military use in World War II; received American Association of University Women's Annual Achievement Award (1945); won the Francis P. Garvan Medal for women in chemistry presented by the American Chemical Society, (1951); starred in the seventh edition of American Men of Science; won the Photographic Society of America Progress Medal; retired from General Electric (1963).

Selected publications:

"Irving Langmuir," Journal of Chemical Education (Vol. 10, 1933, pp. 396–399); "Films Built By Depositing Successive Monomolecular Layers on a Solid Surface," Journal of the American Chemical Society (Vol. 57, June 1935, pp. 1007–1022); with Langmuir, "Built-Up Films of Barium Stearate and Their Optical Properties," Physical Review (Vol. 51, June 1, 1937, pp. 964–982).

In 1933, Katharine Burr Blodgett was carrying out research at the General Electric laboratories when she made the discovery that was to mark the highlight of her career. Her mentor, Irving Langmuir, had directed her to seek a practical application for his findings that oily substances will spread naturally on the surface of water to form a single molecular layer. By December of that year, Blodgett had experimented unsuccessfully with a number of ideas before she decided to add a sprinkling of talc to the film of oil she was observing on a watery surface, in order to see the resulting motion. She then dipped a metal plate into the solution and watched the talc-covered film coat the plate. As she lifted the plate out of the water, she expected the film to stay in the solution, but the film adhered to the plate; submerging the plate again, she was surprised to see a second film layer added to the first. These layers, only one ten-millionth of an inch thick, were the beginning of what would be known as Blodgett's "built-up films" research and would ultimately find widespread application, benefitting not only high-tech users of optical devices like astronomers and photographers, but every driver of an automobile.

Katharine Burr Blodgett was born on January 10, 1898. Her father George Bedington Blodgett was a patent attorney for General Electric, who had moved his family from Boston to Schenectady, New York, in the 1890s, to be director of the patent department at General Electric's newly opened research facilities there. George Blodgett died several weeks before his daughter was born in the family's Front Street home, leaving his widow Katharine Buchanan Blodgett with a young son and an infant daughter. Believing Schenectady to be too small a town for much opportunity, Mrs. Blodgett moved the family several times, first to New York City, where they lived for three years, and then to France and Germany where she hoped the children would learn languages more easily while they were young. A strong believer in education, she eventually returned to the United States to insure that they also retained their native English vocabulary.

Young Katharine's education was unique for a child of her social class. She did not attend school until she was eight years old, when she was enrolled for one year at the public school in Saranac Lake, New York. Following that, she

attended the Rayson School, run by three English sisters in New York City. The emphasis there on the proper use of English-speaking patterns helped to form Blodgett's lifelong habit of carefully thinking before she spoke or wrote. The qualities of exactness, clarity, and conciseness in communication were to be crucial to her future work.

Blodgett was encouraged at the Rayson School to pursue a career in science. Her excellent grades in competitive examinations earned her a scholarship to Bryn Mawr, a school she admired for its high academic standards. Entering the college in 1913, Blodgett welcomed the challenge provided by mathematician Dr. Charlotte Scott and physicist Dr. James Barnes. Barnes, in particular guided Blodgett toward her career as a physicist. By her senior year, she had decided that science offered the best economic opportunities for women but found the prospect of a traditional teaching career unchallenging. She preferred the idea of going into research and hoped that rumors of employment shortages caused by World War I, then under way, might open up opportunities for women in laboratories. That Christmas, she made a sentimental journey to Schenectady, seeking information about the father she had never known, and visited the General Electric Research Laboratories.

Guided through the plant by Irving Langmuir, a distinguished physicist and the laboratories' assistant director, the studious 18-year-old received advice about her scientific training and encouragement that there might be a research position available for her there. Langmuir suggested that she broaden her scientific background

after Bryn Mawr by seeking a master's degree in physics at the University of Chicago.

In 1917, Blodgett moved to Chicago, where she completed her postgraduate academic program within a year. Her thesis focused on chemical activity and problems in gas masks, a timely subject since Allied troops in Europe, confined to a war being fought in the trenches, were suffering from bombardments with gas by the Germans. Since most women of that era were discouraged from studying science at any level, Blodgett's master's degree in physics was a rarity. She was granted a singular opportunity for high-caliber training and fair treatment in the classroom at an institution where male and female students in science were treated as equals.

In the spring of 1918, at age 20, Blodgett became the first woman research scientist hired in the General Electric laboratories. Despite a prevailing bias against female scientists in industry, her scholastic strengths and the wartime shortage of male researchers helped gain her the position, as well as the word put in by her father's former colleagues with the company's administrators. But her career was to be the exception that proved the rule and did not open many doors for other women scientists. Industry at that time generally held the position that the costs incurred in training for high-level positions did not merit the risk of investing in women, who might marry and quit work to raise families. For women in science, it took the backing of a prominent man like Langmuir to pursue research, and most American women who demonstrated a scientific bent found their careers confined to teaching in high schools and women's colleges.

When Blodgett arrived at General Electric, Langmuir was already acknowledged as a premier research scientist. A proponent of pure science, he had received his doctorate from the famous German university at Göttingen and had joined General Electric in 1909. Numerous patents had been filed in his name, including the gas-filled incandescent lamp. Langmuir made Blodgett his assistant; she worked with him on projects that were to culminate in his being awarded the Nobel Prize in chemistry in 1932.

Delving into chemistry and physics, Blodgett spent six years on laboratory problems that included measuring electric currents flowing under restricted conditions, and she collaborated with Langmuir on several papers for technical journals. Blodgett stressed effective communication as the foundation for professional training in science. Her technical writing skills and logical presentation of information earned praise from GE's laboratory director, Dr. William D. Coolidge, for enabling non-scientists to comprehend the material.

Langmuir valued Blodgett's work deeply, calling her a "gifted experimenter" with a "rare combination of theoretical and practical ability." But to qualify for an advanced position, she would have to have a Ph.D. Under his influence, she was able to bypass the stringent admission standards and long waiting list at England's Cambridge University. Arriving in 1924, she studied in the fabled Cavendish Laboratory with some of the world's best physicists, including concentrated study with Nobel Prize winner, Sir Ernest Rutherford. In 1926, Katharine Burr Blodgett became the first woman to earn a Ph.D. in physics from Cambridge.

You keep barking up so many wrong trees in research. … I think there is an element of luck if you happen to bark up the right one.

—Katharine Burr Blodgett

Returning to Schenectady and the GE laboratories, Blodgett became a member of Langmuir's core research group and collaborated with him on surface chemistry. Quickly absorbed in her work, she renewed experiments begun before she had departed for Cambridge. Langmuir at first directed Blodgett to focus on problems improving tungsten filaments in electric lamps, and, according to colleague Lawrence A. Hawkins, "She early showed not only exceptional aptitude for experiment and delicate manipulation but also a high degree of originality and sound judgment, so in later years her researches have been largely independent."

One area of Blodgett's research was atomic structure in relation to thin films. When Langmuir asked her to explore the phenomena related to his discovery of how oily substances spread on water surface, she expanded his research technique, depositing oil films, especially fatty and stearic acids, on a solid surface. The research duo at first found no practical purpose for these layers, however, and in 1933 Langmuir set her the task of seeking some application. Blodgett recalled, "You keep barking up so many wrong trees in research. It seems sometimes as if you're going to spend your whole life barking up wrong trees. And I think there is an element of luck if you happen to bark up the right one. This time I eventually happened to bark up one that held what I was looking for."

In 1933, success arrived finally through her work to uncover the properties of oil film layers, leading eventually to the discovery that the films could be laid down in great numbers. As the acid transferred from the solution to the solid, she also found that films varying in both thickness and color could be created. The plate holding such films reflected rainbow colors like an oily spot in a mud puddle. In pursuit of a practical use for this discovery, Blodgett created a standardized color gauge that could measure the depth of such films to within one micro-inch. According to Blodgett, "Anyone who wishes to measure the thickness of a film which is only a few millionths of an inch thick can compare the color of his film with the series of colors in the gauge." The instrument was simple and accurate, and more affordable than the expensive optical instruments previously used for such measurements.

With Langmuir, Blodgett first publicized her method of depositing successive monomolecular layers of stearic acid on glass in the February 1935 Journal of the American Chemical Society. In June of that year, another article by Blodgett in the same journal, "Films Built By Depositing Successive Monomolecular Layers on a Solid Surface," acknowledged her mentor's influence on her research techniques, as she noted her collaboration with Langmuir, followed by independent research while he was away in the Orient. "The writer is indebted to Dr. Langmuir for urging her to develop further the method described in the previous paper," she wrote, "and for contributing many important suggestions which have been included in this paper." A final paper in the series, "Built-Up Films of Barium Stearate and Their Optical Properties," was completed with Langmuir upon his return and published in the June 1, 1937, Physical Review.

In December 1938, General Electric announced that Blodgett was the inventor of nonreflecting glass, a development that grew out of her efforts to refine her technique of depositing films on solids. When her minutely thin oil films were layered onto a pane of glass, she found that the panes did not reflect light, a discovery that was to usher in an era of specially created optical devices, including windshields, telescopes, periscopes, and camera lenses. In her research, Blodgett had applied a coating of 44 layers of one-molecule-thick transparent liquid soap to glass to reduce surface reflections, producing a total thickness of only four millionths of an inch, or one-fourth the length of an average white light wave. The glass meanwhile appeared invisible, because the soap film reflection neutralized the reflection, and the two sets of light waves canceled each other out. The soap allowed 99% of the light to pass through the glass, and no light was reflected.

Two days after GE's announcement, two physicists at the Massachusetts Institute of Technology, C. Hawley Cartwright and Arthur F. Turner, stated that they had made non-reflecting glass by evaporating calcium fluoride in a vacuum and applying it to glass. Both Blodgett's product and theirs were marred by the delicacy of the films, which were easily rubbed off the underlying glass. It was left to other scientists to develop means for making the coatings more durable, and manufacturers of lenses and optical equipment have advanced well beyond her original fundamental research. In the beginning, however, it was due to the overwhelming support and publicity given to her achievement by GE that the discovery found so many immediate applications.

The outbreak of World War II shifted Blodgett's focus at General Electric to military needs. Part of her research was to devise an improved generator to produce smokescreens for obscuring ground movements of troops from enemy forces, work which has been credited in Science Illustrated with saving thousands of lives during the Allied invasions of France and Italy. She also was assigned the problem of creating better methods for de-icing the wings of airplanes.

After the war, in 1947, her research for the Army Signal Corps reunited her with the study of thin films for the purpose of designing an instrument to measure humidity in the upper atmosphere. Blodgett's model, carried aloft in weather balloons, proved to be insufficiently sensitive at high altitudes. She was then vital in recruiting Vincent J. Schaefer, who had participated in early weather modification experiments, to join Langmuir's staff. Schaefer, with the assistance of Blodgett and others, invented the technique to create artificial rain by dropping dry ice pellets into clouds from airplanes. According to the April 9, 1951, issue of Chemical and Engineering News, Blodgett also aided in the construction of a high-resistance electrical material, formed by heating lead glass in hydrogen to produce thin, low-conductivity surface films that remain stable at high voltages.

The research on thin films gained Blodgett international recognition. She was named a fellow of the American Physical Society and a member of the Optical Society of America, and received honorary doctorates from many colleges, including Brown University and Russell Sage. On March 29, 1945, she was one of the first recipients of the Annual Achievement Award of American Association of University Women, one of the highest honors available to a female scholar. In April 1951, she was honored by the American Chemical Society with the Francis P. Garvan Medal for women in chemistry for her work in surface chemistry. The only scientist honored by Boston's First Assembly of American Women of Achievement, she also presented two James Mapes Dodge Lectures at the Franklin Institute, was starred in the seventh edition of American Men of Science, won the Photographic Society of America Progress Medal, and was honored in her hometown of Schenectady for her many accomplishments with the celebration of Katharine Blodgett Day.

In addition to her scholarly research and writing, Blodgett penned a biographical sketch of Langmuir which provided readers with insights into his family and home life as well as her own professional interaction with her mentor. She frequently visited the Langmuir family when they entertained in their home at Christmas and at their camp at Lake George. According to Blodgett, Langmuir's "praise is discerning and wholly without personal bias," and the "laboratory worker who wins from him just the two words, 'Very fine,' had won a compliment greatly to be prized." An admirer of the discipline he brought to the laboratory, Blodgett admitted that Langmuir was "stern toward workers whose mental processes are vague and whose theories are badly thought out" because "he has never tolerated stodginess in his own mental faculties." He had enthusiasm only for researchers whose intelligence he respected, especially Blodgett, and could act icily toward everyone else. Like Langmuir, Blodgett found little time for people or concerns not oriented toward research. Despite her ground-breaking technological innovations, she resisted the modernization of her own laboratory furnishings. According to one colleague, "In all her career as a research scientist Dr. Blodgett has used a battered old table and scarred wooden stool, with which she refused to part when her laboratory was moved into a new glass and steel building."

Soon after returning from Cambridge, Blodgett bought a brick house in downtown Schenectady at 18 North Church Street, near the house where she was born. A mere five feet tall, she was described as "a modest, plump, pleasant-faced woman with an uptilted nose and merry eyes." She enjoyed stargazing and nature, and owned land two hours from her home, near the Langmuirs at Lake George, where she could unwind from the pressures of the laboratory. Her leisure hours were spent digging into the rich earth of her garden, playing bridge with friends, shopping for antiques, attending the Presbyterian church, and participating in civic affairs as treasurer of the Travelers Aid Society. What she relished most, however, was her research work and interaction with colleagues, and she served eagerly as president of the General Electric employees' club.

After retirement from General Electric in 1963, Blodgett enjoyed carrying out horticultural experiments. Gardening continued to be her favorite form of relaxation, except at those times she admitted to being "thrown into a shrieking panic in meeting face to face a common garter snake."

Katharine Blodgett died at home on October 12, 1979, at age 81. In the 1980s, two of her papers on what has become widely known as the Langmuir-Blodgett film were still important enough to be cited an average of 100 times each. Her written work about methods in chemistry and biophysics remain useful to contemporary researchers, who quote her techniques and research philosophies. The vitality of Katharine Burr Blodgett's techniques have transcended time.


Barlow, W.A. Special Issue on Langmuir-Blodgett Films. Lausanne: Elsevier Sequoia, 1980.

"Blodgett, Katharine Burr," in Current Biography. NY: H.W. Wilson, 1952.

"Katharine Burr Blodgett," in Physics Today. Vol. 33. March 1980, p. 107.

Yost, Edna. American Women of Science. Philadelphia, PA: J.B. Lippincott, 1955.

suggested reading:

Hawkins, Lawrence A. Adventure into the Unknown: The First Fifty Years of the General Electric Research Laboratory. NY: William Morrow, 1950.

Rossiter, Margaret W. Women Scientists in America: Struggles and Strategies to 1940. Baltimore, MD: The Johns Hopkins University Press, 1982.

Wise, George. Willis R. Whitney, General Electric, and the Origins of U.S. Industrial Research. NY: Columbia University Press, 1985.

——. "A New Role for Professional Scientists in Industry: Industrial Research at General Electric, 1900–1916," in Technology and Culture. Vol. 21. 1980, pp. 408–429.


Irving Langmuir Collection, Library of Congress, Washington, D.C.

Blodgett's and Langmuir's personnel files, manuscripts, laboratory notebooks, and research notes, as well as other archival materials, are available at the General Electric Research and Development Center, Schenectady, New York.

Elizabeth D. Schafer , Ph.D., Freelance writer in History of Technology and Science, Loachapoka, Alabama