E. Fischer The Weizmann Institute of Science Rehovoth, Israel
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Hirshberg-In
In the .fast-moving world of today people, including scientists, tend to live in the future or, a t best, in the present, and there is little room for sentiments regarding the past. It is therefore all the more appreciated by my friends a t home and myself that Dr. Wyman and the organizers of this Symposium took the initiative to devote this session to Yehuda Hirshberg's memory, and also asked me to tell you a little about the man and his work. Hirshberg's life was moulded to a large extent by his Jewish heritage and his Zionist background, both of which had a profound influence on his personality and career. After finishing high school in-~oland,Hirshberg went to Palestine in 1923 as a pioneer and joined a collective settlement. This was in line with the Zionist ideals of that period, which put the accent on the trans. formation of the Jewish intellectuals into agricultural workers. However, after a year he fell ill with malaria, like so many of his comrades, and went to Jerusalem to recuperate. He started working as a manual laborer, but at the same time could not withstand the attraction of the Hebrew University and enrolled in it. The science division there was at that time still in its embryonic stage, but full of enthusiasm, with teachers and students forming a sort of family. After five years of combined labor and studies he This paper introduced the session set aside t o commemorate the late Professor Y. Hirshherg's contributions to the field of reversible photochemical processes at the April, 1962, International Symposium on Revenible Photochemical Processes in Durham, North Carolina, which was sponsored by The U. 8. Army Research OfIice. Other original papers presented at this Syniposiiun will appear in the Jownal of Physical Chemistry.
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journal o f Chemicd Education
Memoriam
graduated, and soon won a scholarship to the University of Brussels. I n the archives of our late President Weizmann we found the copy of a letter which he wrote to a friend in 1930. I t read as follows: I understand that at t h ~ Universily of Brussels there is a Palestinian boy, a Mr. Yehude. Hirshberg, who is supposed to he a brilliant chemist. I have heen told that in TJniversity circlcs he is known by the name of the "miracle of .Terusalem." He hardone s, considerable amount of good work at the University of Jerusalem; and I enclose ropies of the course of studies he has taken. He is in straitened circumstances and would require a subsidy of shout £4 per month, if he is to proceed with his scientific work.
Apparently Hirshberg got this financial help, because a year later he completed his post-graduate studies, won his doctorate with great distinction and attained an assistantship in the laboratory of Victor Heri, one of the founders of modern photochemistry and spectroscopy, and later worked with Errera, who was also an outstanding physical chemist. However, Hirshberg longed to return to Israel; and when asked by Weizmann to join the staff of the Sieff Institute in Rehovoth, which was just founded a t that time, he gladly agreed and in 1933 returned to Israel. Thus began his life-long association with Weizmann and the Sieff Institute, which later developed into the present Weizmann Institute. The 1930's and then the war years were a difficult period for the few Israeli scientists then existing. They had to struggle continuously with adverse external conditions, including of course the fact that they were a Small isolated group, remotefrom the centersof research in Europe and America. Many of my own teachers belonged to this generation, which in a way was the "desert generation," who sacrificed their own
Dr. Hirshberg belonged t o the ever-derreasing group of scientists who consider their day well spent a t the bench, away from the many distractions ~ h i c hlife presents today. His pride in being srtive in the laboratory war an inspiration to his hard-working group and surely to all of us. I well remember his phenomenal skill aq an experimenter, 2nd often admired his quick and nimble hands, and above all his al~ilityto perceive results. In an age where instrunrent&x~,nutomatic recording and all such gsdgeta have become the be-all and end-all of experimental work, his obsewittiond skill was a pleasure and an example to behold. Itwas his skill and his patience a t the bench that led to his observations of the complexphoto-behavior of organic compounds on which he and his group have been working. It is rare today that s man can show s record of research sround n central theme; Yehuda Hirshberg worked on the interaction of radiation with organic nmleeules over 26 years of scientific activity, and throughout those years he constantly succeeded to maintain a fresh approach to his central problem. We shall never know now haw far his own work would have progressed; but no better t,ribute ran be paid t o Yrhuda Hirshberg's research than this: since the publication of his major papers interest in the phenomenon of phobochromy has e m h d e d worldwide.
scientific careers in order to build the foundations of Israeli science today. Not all of them lived t o have the satisfaetaion of seeing and harvesting the fruit of these hard years. Their effort has therefore to be appreciated all the more. However, Hirshherg lived to have this well-deserved satisfaction. Let me just outline his research until 1950. His first photochemical work dates back to 1933, when he studied, with Victor Henri, the photochemical decomposition of glycine. Later, already a t the Sieff Institute, he investigated the photochemistry, in water solutions, of alcohols and aldehydes, and then the photochemical deamination of amino acids. This was followed by resparch on the photochemical interaction between primary and secondary alcohols and ketones, and then photochemical decomposition of solid hydrogen compounds a t low temperatures. All this and related work is what is nowadays called "classical solution photochemistry." Concurrently he naturally got involved in absorption spectroscopy and in this field gradually moved through the various experinlental stages, starting with the slow and laborious spectrophotographic methods of the early years, then passing the "Beckman DU" stage, and ending with the Cary Recording Spectrophotometer. At the same time he investigated fluorescence spectra and tried, like others, to find some correlation between t,he spectra and the structure of large organic moleculrs, as well as their carcinogenic activity. A sojourn in Ottawa a t Norman Jones' laboratory resulted in papers on the UV spectra of carhoxylated naphthalenes. His first publications on photo-isomerization, involving arylated hutadiene, appeared in 1950. At this period he became interested, through Ernst Bergmann, in thermochromic dianthrones, and late in 1950 made his discovely of the phenomenon named by him "photochromism," namely the reversihle transformation of these colorless compounds into colored forms by the action of ultraviolet light. Since then the term "photochromism" has become quite popular among xvorkers in this field and, although it is not too well-defined, I am glad that Hirshberg is also commemorated in this way. This first discovery was soon followed by a similar one with spiropyrans, and then by the reverse reaction with visible light. These exciting topics of research gave Hirshberg an ample opportuuity to use his knowledge and capabilities to the fullest extent. His zeal and enthusiasm were boundless, and I should mention in particular his stuhborn belief that these systems might eventually be used as information storage and handling devices, as well as image-forming media. This was in fipite of the declared skepticism and criticism of many of his colleagues, who did not appreciate sufficiently the man and his work. The results of those fruitful years are well-known. To describe Hirshherg during this period, let me quote a colleague who, unfortunat,ely, said these words only as an obituary :
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Despite his success, Ilirshberg never ceased to he a "man of the people," being on friendly terms xvith everybody, irrespective of grade or standing. His personality was marked by boundless devotion to his work, willingness to help, and eagernpss to make a friend of whomever he met, a goal which he achieved almost always thanks to his rich .Jewish humor and his good-heartedness. His last years were marred by great suffering because of his many maladies. Xevertheless, he put up a stuhborn fight against his disease and refused t o give in. Ile was active in the laboratory and full of plans to his last day, and succumbed to a heart attack while still wearing his white laboratory coat. It is sad indeed that he thus did not live t o see the widespread applications of photochromism, which are apparently ahead of us today.
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Volume 40, Number 3, March 7 963
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