WERNER KUHN On His 60th Birthday

Anybody who knows Professor Werner Kuhn or looks a t the picture on top of this page will strongly reject the hypothesis that he is 60 years old. Yet, i t is an undeniable fact that Werner Kuhn was born in Maur (Kanton Zurich) on February 6, 1899, as a son of the parish G. Kuhn, graduated from high school in 1917, and obtained his Master’s Degree in Physical Chemistry and Electrochemistry a t the ETH in Zurich in 1921. Then he moved to the University of Zurich and got his Ph.D. in 1923, under the guidance of Victor Henri, with a study on the photodecomposition of ammonia. Through this eminent representative of classical photochemistry Kuhn was introduced into the action of light on chemical molecules, a topic which he pursued with remarkable success.

As the outstanding graduate of the year a t the University in Zurich, Kuhn was awarded a Rockefeller Fellowship and, like many other promising young scientists of those days, decided to continue his studies in the mecca of theoretical physics-with Niels Bohr in Copenhagen. He quickly ab- sorbed the spirit of Bohr’s quantum theory with its postulates and selec- tion rules and was particularly attracted by the principle of correspond- ence. With extraordinary speed he succeeded to turn learning into orig- inal research by formulation with Thomas of the “Summensatz,” which soon became a pillar of the dispersion theory of light. A rapid and thorough pickup of new ideas in a field of scientific endeavor, plus the creative im- agination to add almost immediately his own contributions, was exemplified in this work and remains Kuhn’s strongest weapon up to the present time. Dispersion of light, optical activity of molecules and crystals, kinetic theory of rubber elasticity, thermodynamics and hydrodynamics of polymer solutions, methods for the separation of isotopes, struct,ure of the interior of the earth, and theory of kidney functions-all these widely different topics aroused his interest and each of them was left by Kuhn in a sub-

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stantially promoted state by the contribution of pointed and critical ex- periments and the development of theories which were unsurpassed for their clarity and applicability.

At this point it is particularly fitting to remember that Kuhn was one of the earliest pioneers in the physical chemistry of polymers through his theory of cellulose degradation, rubber elasticity, and solution viscosity. He did not only lay the fundamentals, but he kept on expanding and refining his ideas and equations and so remains in the forefront of progress up to the present time. There is no doubt that he will continue to lead the field in the future.

Skillful both in the performance of delicate experiments and in the mathematical formulation of difficult theories, he was able to tackle successfully problems of great complexity in any state of their develop- ment.

But beyond the many articles and books in which Kuhn has formulated the results of his scientifih work, he has greatly influenced the present generation of polymer physicists and chemists by his personality. Kuhn, who speaks four or five languages fluently, is an outstanding figure a t all international meetings, was one of the Section Presidents in IUPAC, and has served as chairman or discussion leader a t innumerable occasions with success and distinction. Kuhn is an inspiring teacher; his courses are models for clarity and simplicity; his scientific presentations are truly classical in their conciseness and have been famous for years a t Symposia and Conferences all over the world.

It could not be but that a man of such talents and energy would surround himself with an ever growing circle of friends and pupils and, as the years passed along, would grow into one of the representative figures of our Science. There he stands now, sixty yea.rs young, as a pace maker of progress, as a good-natured, benevolent teacher, and as a warm friend with an excellent sense of humor and with the never failing readiness to give help wherever it is needed. At this occasion it is a great pleasure for the writer of these lines to summarize the feelings of all polymer chemists and to wish our friend many more years of merry and sparkling activity to his own satisfaction, to the joy of his wife and children, and to the benefit of all of us.

H . Mark