BLODGETT, KATHARINE BURR - Jan. 10, 1898 - Research physicist and chemi st Address: b. c/o Resear ch Laborator y, Company River Rd., Schenectady, N. Y., h. 18 N Church St., Schenectady, N. Y.

NOTE: This biography supersedes the article which appeared in " Current Biography"in 1940.

A research s cientist in surface , Katharine Burr Blodgett has received widespread recognition for the practical application of her work on t hin films, for the invention of a devi ce for measuring t he thickness of films within one micro-inch, and for the development of nonreflecting "invisible" glass .. Her lifelong s cientific associate, Dr. Irving Langmuir, winner in chemistry, has described Dr. Blodgett as "a gifted experimenter" with a "rare combination of theor etical and practical ability" . She has been associated with the General Electric Laboratories in Schenectady since 1918, except for two years of study und er Sir at the Cavendish Laboratories of Cambridge University, whe r e shawas the first woman st2dent to recei ve a Ph.D. degree in . Bor n in Schenectady, , on January 10, 1898, Katharine Burr Blodgett i s the daughter of George Bedington and Katharine Buchanan (Burr) Blodgett, who al so had an older child, a son . The father, a patent attorney for the General Electric Company, moved f rom Boston soon after the company became estab­ lished in Schenectady. Katharine was bor n a few weeks after her father's death; Mrs. Blodgett l ater took her son and daughter to New York City, where t hey l ived for thr ee years. Following a sojour n i n France, they r eturned to the United States for a few years, after which the children traveled to Ge rmany . Katharine Blodgett 1 s educati on wa s begun at the age of eight, when for one year she attended a public school in Saranac Lake, New York. For t he remainder of her elementary and her secondary schooling she was enrolled in a private institution in New Yo rk City. Her grades in a competitive examinati on won her a matriculation scholarship to Bryn Mawr for 1913-14, where the teaching of James Barnes inspired her t o study physics. Because of her f ather 's work., Katharine Blodgett had a sentimental feeling for Schenectady~ Thu~during t he Christmas vacation of her senior year the eighteen-year-old college girl visited the General Ele.ctri c plant in that city. Her guide through t he l aboratories was Irving Langmuir, who advised her to take further scientific training. Accordingly, af ter graduation in 1917, she enrolled for post-graduate studies at the University of Chicago. Completing her thesis on problems in the chemistry of gas masks in 1918., she obtained the MoS c . degr ee. -2-

Despite t he prevaili.ng bias against wome_n scient ists, in 1918., Miss Blodget t, aided by her scholastic standing, a wartime shortage of personnel, and her father's old f riends , became the f irst woman r esearch scientist in the General El ectric l aboratories. Working i n the bor derline area between physics and chemi stry, she assisted Dr . Langmuir for t he f ollowing six years on such studies as the quantitative measurement of flow of el ectri c current under pre- . scribed condi tions. During this period she and Langmu i r jointly published several research papers i n t echni cal jour nal s. Langmuir appreciating her p otentiali ties, advised her to increase her knowledge by studying at Cambridge Un iversity. In 1924 she was admitted t o the British institution, where she studi ed under Sir Ernest Rutherfor d., Nob el Prize- wi nner , at the Cavendi sh Laborator ies. Two years later she received the first Ph eD. degree i n phys i cs ever awarded to a woman by Cambridge. Then, back in Schenectady, Dr . Blodgett pursued her wo r k with Dr. Langmuir for about five additional years on the improvement of t ungsten filaments in electric lamps and on other problems, the t wo researchers continuing to publish joint papers. I n 1933 Langmuir asked her to work on phenomena rel ated to his discovery that oily substances on t he surfa ce of water form a single molecular layer. It was in t he cour se of many years of research along these l i nes that Dr., Blodgett made her main contri bution t o science--methods of constructing films of infinitesimal thinness. The invention of the "color gauge , " whi ch permits f i lm measure­ ment within one micr o-inch., began vd th Dr. Blodgett I s discovery i n December 1933 that monomolecular layers of stearic , each abou t one ten-millionth of an i nch in thickness, could be su ccessively deposited on to a plate lowered into the solution. This enabl ed her to construct films in a series of progressive thicknesses, of which each reflects a characterist ic color in whi te light. Her method of depositing sheets of barium stearate on pl ates enables a standardi­ zation color gauge to be con stru cted., "Anyone who wishes to measure t he thickness of a film which is only a. few millionths of an inch thick.," she said, " can compare the color of his film with the series of colors i n t he gauge . The step on the gauge t hat matches his film in color will give him a measure of its t hickness. " Thi s device eliminates expensive optical instruments in the measurement of transparent or semitransparent films by metallurgists, physicists, , and other technicians . Dr . Blodgett also showed interest in the application of t hi s method to the measurement of t he t hickness of biological tissue s . The General Electric Company announced in December 1938 t hat Katharine Blodgett had succeeded i n developi ng a nonreflecting "invisible'' glass. Ordinary glass is visible because of the light ray s which a.re reflected from its surface ., and when a f ilm i s placed upon t he glass, t here is a reflection f rom the film as we ll as f r om the glasss Dr .. Blodgett discovered that a coating of forty-four layers of one-molecule- thick transparent liquid soap, of -3- about four-millionths of an inch or one-fourth the average wave length of white light, made sheets of glass invisible. Since the reflection from the soap film neutralizes the reflection from the glass itself, the crests and troughs of the two set of light waves cancel each other, thereby eliminating reflected light. At the same time, the soap varnish is a good conductor of light, permitting 99 per cent of the light striking it to pass through. The one aspect of Dr. Blodgett's work on nonreflecting glass requiring further research was the development of harder coatings which c~uld not be wiped off9 Some of the applications of the invention are seen in automobile windshields, shop windows, showcases, cameras, spectacles, telescopes, picture frames, and submarine periscopese Within two days after the woman scientist's discovery was made kno'W!l, two other scientists announced that they had also devised an "invisible" glass by depositing the condensed vapor of metallic fluorides on glass. One of Dr. Blodgett 1 s assignments i n World War II was the problem of riduing airplane wings of ices She also helped device a new kind of smoke screen which, according to "Science Illustrated", saved thousands of lives in the North African, Italian, and later invasions. She did research in 1947 for the Army Signal Corps on the use of thin films for the development of an instrument to measure humidity which could be carried into the upper atmosphere by weather balloons; the available devices did not react with sufficient rapidity during the balloon's fast ascent, nor were they adequately sensitive at high altitudes. Her current work, as reported by "Chemical & News" on April 9, 1951, involves the construction of a high-resistance electrical material obtained by heating lead glass in , a process producing a low-conducti­ vity thin surface film whi ch is stable at high electric potentials. During the course of her years at GE, the woman scientist was instrumental in bringing to Langmuir's staff Vincent J. Schaefer, who invented t he technique of producing artificial rain by having airplanes drop pellets into cloudse Another of her colleagues has been Robert Smith-Johannsen, who worked on coatings to prevent icing on airplane propellerse Scientific journals have published Dre Blodgett's papers, which deal with discharges in gases, surface chemistry, and the development of nonreflecting glass. She has received honorary doctorates from Elmira College ( 1939), Western College ( 1942), Brown University (1942), and Russell Sage College (1944)~ The American Association of University Women on March 29, 194~ presented her with the Annual Achievement Award of $2,500 for her research on thin films. In April 1951 she received the Francis P. Garvan Medal, honoring women in cherristry, from the American Chemical Society for her work in surface chemistry. On the occasion of this meeting she addressed the society on the subject "Interference Colors Reflected by Thin Films." Two other her.ors came to her in 1951. She was the only scientist, reported"Look", honored by Boston's First Assembly . ' '

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of American Women of Achievement (in May); and in that summery Schenectady celebrated Katharine Blodgett Day. A fellow of the American Physical Society,she is also a member of the Optical Society of America. 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 the new glass and steel building in Schenectady. Active in Schenectady civic affairs, she has served as treasurer of the Travelers Aid Society, is a member of the Zonta Club, and is a past president of a GE employees' club. Her church affiliation is Presbyterian. Katharine Blodgett lives in a house in downtown Schenectady. Gardening is her favorite vacation recreation, though the "Times" has reported that she "is thrown into a shrieking panic in meeting face to face a common garter snake." Her other hobbies are amateur astronomy and collecting antiques. She is. five feet tall and has been described as "a modest, plump, pleasant-faced woman with an uptilted nose and merry eyes."

References Chem & Eng N 29:1408 Ap 9 1 51 Christian Sci Mon O 24'44 por Ind Wpman 19:29 Ja '40 por p3 Look Ag 28 1 51 por NY Post Je 4 '41 por NY Times S 24'39; Mr 15 '51 por Sci Ilus 2:9-11 D '47 Time 33:33 Ja 9'39 por American Women, 1939-40 International Who's Who, 1950 Who's Who in America, 1950-51 Yost, E. American Women of Science (1943)