JOURNAL OF CHEMICAL EDUCATION
ARNOLD EUCKEN RALPH E. OESPER University of Cincinnati, Cincinnati, Ohio
A m o m THOMAS EUCKEN, one of the leading physical of Ludwig Knorr (1859-1921), the organic chemist chemists of our time, was born a t Jena, on July 3, 1884. The instruction in mathematics was also excellent His father, Rudolf C. Eucken (184&1926), was pro- In 1905 he enrolled a t the University of Berlin, where fessor of philosophy and recipient of the 1908 Nobel he worked in the Institut directed by Nernst. The prize for literature. One of the maternal great grand- doctorate thesis bore the title "The stationary state fathers was the physicist Thomas Seebeck (1770- between polarized hydrogen electrodes." The oral 1831), renowned as the discoverer of thermoelectricity. examination (1906) was rated "summa cum laude"; No particular branch of science attracted the boy it was taken while the candidate was fulfilling his year during his years a t the humanistic Gymnasium in Jena. of military training. In 1908 Dr. Eucken returned to He had a love for the outdoors, and his normal youthful Berlin as assistant under Nernst; he worked in the urge for collecting turned to butterflies, rare orchidaceae, fields of electrochemistry and heat theory. The etc. Later, he became interested in the local bird life, habilitation as Privatdozent in 1911 was under the while exotic birds were raised on a fairly large scale at sponsorship of Nernst and Emil Fischer; the dissertahome. As a grown man, this love of nature led him to tion was entitled "The temperature dependence of the become an enthusiastic mountain climber. heat conductivity of solid nonmetals." In 1913 he was After graduation (1902) he entered the University of appointed section chief of the physical chemical laboraKiel. His decision to become a physical chemist tory of the University of Berlin. eventually was due in large measure to Heinrich Biltz, During World War I Dr. Eucken served both in the whose inorganic laboratory course, in contrast to those field and the laboratory; his talents were utilized on given in most other universities, was based almost various scientific problems. Though he m-as called to entirely on the newer achievements of physical chem- head the department a t the Technische Hochschule istry, particularly the Arrhenius theory of ionic dissocia- in Breslau as early as 1915, he could not enter on these tion. The lecture and laboratory work in physics was duties and responsibilities until January, 1919, i. e., conducted by Ph. Lenard. Transferring to Jena, after the demobilization. He came to his present high Eucken was permanently impressed by the personality position, Director of the Institut fiir Physikalische
OCTOBER, 1950
Chemie a t the University of Gottingen, in 1930, where his immediate predecessor was Gustav Tamman (186119381, who in turn had succeeded Walter Nernst (1864-1941). Electrochemical topics engaged Professor Eucken's special attention in 1907 and 1908. Beginning in 1909 he dealt especially with heat theory, and carried out particularly a series of measurements of specific heats a t low temperatures. The method which is still used for such determinations was worked out by Eucken a t the suggestion of Nernst (1909). A study (1912) of the specific heat of gaseous hydrogen a t low temperatures attracted considerable attention; for the first time the decrease of the specific heat of this gas t o the value holding for mono-atomic gases was followed quantitatively. I n another study (with F. Schwers) the so-called Ts-law for change of specific heat of solids a t low temperatures, that had been derived theoretically by Debye, was experimentally verified for the &st time. After World War I Professor Eucken's most important researches dealt with an intensive experimental study of the question as to vhether and to what extent the Nernst heat theorem may be regarded as holding rigidly under all conditions. The finding that this is not true in all cases led to a series of further studies designed to explore the heat motion in solids; the study stressed materials whose molecules are capable of rotation in the solid state. Another set of researches was devoted to the thermal conductivity of solids (metals and nonmetals). Even in his habilitation essay published in 1911, he had reported the discovery of the 1/T-law, which is characteristic of nonmetallic crystals. Precision measurements to determine the specific heat of gases were carried on from about 1928. The most important result was the detection of the differencein the specific heat of ortho- and para-hydrogen, as demanded by the quantum theory. The objective of still other studies was primarily to determine whether the Planck-Einstein formulas for calculating the specific heat of gases are correct, a point which a t that time could by no means be taken as established. Studies of heavy water constituted another field of researches. These investigations in the Gottingen laboratory were made with the collaboration especially of Clusius and Bartholom6. More recently, Professor Eucken has turned to reaction kinetics. The question of energy exchange between gas molecules seemed to be of importance for some of these problems, and studies of the dispersion of sound in the ultrasonic region were undertaken t o clear up some of the points. These led to remarkable results in so far as it was found that the exchange of the vibrational energy is facilitated by a certain chemical affinity of the colliding participants. Interfacial phenomena, especially gas adsorption, has claimed his active interest since 1914. From 1940 on, contact catalysis was an important field of research in his laboratory. Several recent (since 1946) studies have dealt with the
configuration of associated liquids (water in particular) and related problems, such as the ion hydration in aqueous solutions. An adequate view of his extensive research interests can best he obtained by consulting the Collective Indexes of Chemical Abstracts. Professor Eucken has long been concerned with the important question as to the most fruitful method of bringing about a closer collaboration between the representatives of pure (theoretical) science and those of the applied (practical) branches. To this end some of the researches in his laboratory were planned primarily with practical objectives, and their successful outcome was made possible solely through the aids of modern science. His efforts t o knit more closely the ties betaweenscience and technology, i. e., theory and practice, met with approbation, especially within the Vereins deutscher Ingenieure, which for a time made him the chairman of a professional committee, whose special task was t o further a better theoretical exploration of the production processes used in German industry. The fruits of Professor Eucken's reseaches are set down in numerous papers, principally in the Zeitschrijt far physikalische Chemie. His literary output has been extensive, both as an independent author and also as collaborator and editor in collective volumes and sets. Much of his writing has been motivated by the desire to rornhnt the pn)~rrssirespet.idiuutio~loi stu11.v rhat is ~ro
