The Professional Life of Emma Perry Carr Bojan Hamlin Jennings Wheaton College, Norton, MA 02766 Emma Perm Carr heloneed to an international erouu of chemists who helped clarify the relationships betGeen-the structure of organic compounds and their ultraviolet absorption spectra &ring the-first half of the 20th century. AIthough she alone is not credited with any single major hreakthrough in chemistry, her professional life provides a vivid portrait of a scientist who vigorously and genially made significant contributions to the field through research and teaching. Early Years Emma Carr heean teachine a t Mount Holvoke Colleee even before she received her uidergraduate degree, and with the exception of time awav to finish her education she remained there for the rest bf her professional life. She first came to the college as a sophomore in 1899, her freshman year having been spent at Ohio State University, less than 100 miles from her home in Coshocton. At the end of her junior year, she interrupted her studies and worked for the next three years as an assistant in the Mount Holyoke Department of Chemistry. She then returned temporarily to the middle west and enrolled a t the University of Chicago, where, as one who often managed the unusual, she was a candidate for an undergraduate BS degree while a t the same time supporting herself by working as a graduate assistant. After receiving her BS degree in 1905, she became an instructor in chemistry a t Mount Holyoke. In 1907 she was granted a leave of ahsence for graduate study a t the University of Chicago and in 1910 received her doctorate under the diiection o f h l i u s S~eiglitz.She then returned to Mount Holyoke, and within three years, at the age of 33, was made Full Professor and Head of the Deuartment of Chemistw. - .a post she held until her retirement in 1946. Although her graduate work had not included training in spectroscopy, Emma Carr nevertheless chose it as a subject for research a t the college. Not only did she recognize its value as a tool for obtaining information about the molecular structure of organic molecules, hut, in addition, she thought spectroscopic investigations would present an excellent opportunity for students and facultv to work tozether-a progressive idea a t a time when undergraduate research wasitill rare. In 1913 she persuaded the college to buy a small Fery spectrograph, and she began learning how to use it. The instrument was crude, and information that can be obtained in a few minutes todav then took davs of skilled technical work and tedious analysis. The frequencies of absorption could he determined hv comoarison with a standard photograph of the known emissionspectra of several elements, hut there was no wav of makine precise measurements of the intensities of absorption. he Mount Holyoke group used the"Hartley MethodWofapproximatine inrensities by relating absorptivity to the thickness of solution needed to effect total absorption a t a given frequency. In 1918 the first publication from Mount Holyoke, "The Ahsortion Spectra of Some Derivatives of Cyclopropane", appeared in the Journal of the American Chemical Society ( I ) . In the winter of 1919, Emma Carr was making arrangements for a leave of ahsence fromteaching. She had originally intended to go t o Scotland to study spectral theory and to learn new technioues from A. W. Stewart a t the Universitv of Glasyow. He wrote to her in March, however, saying that the war had wrought considerable confusion in the academic
communitv of the British Isles. causine uncertaintv about his next appointment. He suggested that she plan to go to Queens University in Belfast instead, since he had applied for a position there himself. His cordiality must have made Belfast seem very attractive (2): With regard to the place, I was on the Staff there for five years and have a good many friends in the city to whom I could give you introductions which might make you feel that you were not entirely among strangers;and I am sure that you would fing [sic] the people in the Chemical Department expremely [sic]nice to deal with. The Chemical Department there has been runvery much on the lines of a social cluh-I am not referring to their work, of course!-and I think they would make you feel at home at once. I merely mention these points because I always have helieved that people do better work if they are comfortable;and I am afraid that I was tosomeexpent [sic]responsible for the spirit of that laboratory. Carr followed his suggestion, and in Belfast she learned the most advanced ultraviolet techniques of the early postWorld War I period. Assoclatlon with Vlctor Henrl In 1924 Emma Carr received from the editors of the "International Critical Tables" (ICT) an invitation that had significant conseauences for her future work. After askine h& "to accept appointment as Cooperating Expert in char& of the preparation of data pertaining to 'Absorption Spectra'", the letter from the ICT Board of Directors further explained that two European professors, Victor Henri of the University of Zurich and Jean A. E. M. Becquerel of College de France in Paris, would also he Cooperating Experts on spectra (3). Carr accepted the invitation immediately and made the decision to ask Henri if she could come to Zurich to work in his laboratory while carrying our her ICT otdigations. After home difficulties in making contact due to Henri's distaste for answering letters, arrangements wrrs finally made, and, with on affertiunate send-off from her students. she left for Zurich in February, 1925. It must have taken courage to go from a small New England woman's college to a large, male-dominated university overseas. In Zurich, Erwin Schroedinger was formulating his wave equation almost next door, indiiative of the intellectual energy that surrounded her. Outgoing even in a foreign countrv. Carr formed strone orofessional and oersonal ties with \iictor Henri and his iakily. He was interesting and stimulatine. and his laboratorv was eouinned . .. with the most advanced ;ltraviolet absorption instruments of the day. "The eauioment in luxuries is splendid." she wrote to the Mount ~ o & o h Alumnae e ~ u l l e t i n"hut , in everyday necessities nil-when I asked for a funnel they said.. 'Oh,. we make those when we need them' " (4). Although Emma Carr would have likedto have spent most of her time learning new spectroscopic techniquesand theuretical approaches, it was important for her to meet her ICT assignment. Doing so meantiearching through and evaluating publications from all over the world, while at the same time trying to coordinate her efforts with those of Henri and Becquerel, both of whom were casual about details and deadlines. Despite these demands. however. Carr did not forget her res~onsibilitytowards her students hack home, and she found time to write up the results of research she Volume 63 Number 11 November 1986
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had done with Marie Dobbrow on the ultraviolet spectra of some derivatives of anisalhydantoin (5). Before returning to the United States, Emma Carr was chosen by the National Academy of Sciences and the National Research Council as a United States delegate to the International Union of Pure and Applied Chemistry (IUPAC), another indication that her reputation was hecoming firmly estahlished. Electromers
In 1926 Carr was approached by Morris S. Kharasch, not yet famous for his work with Frank Mayo that identified peroxides as the cause of deviations from Markovnikov's rule. Much less to his credit, Kharasch in the late '20's was a strong advocate of what he called "electromers".' Unfortunately, what started out as a tentative theory soon turned into a misguided conviction. Kharasch proposed that electronic isomerism would occur in vicinally disubstituted ethylenes in which the -R groups on the unsaturated carbons are of hut slightly different electronegativity. In particular, he was working with 2-pentenes. He pictured two electromeric forms, or electromers, differina only in the position of one of the pairs of electrons that co"sti
