CHANDLER LECTURE The Chandler Lecture for 1935 was delivered a t Columbia University, Xew York, on May 28, 1936, by William Francis Giauque, of the University of California. P r o f e s s o r Giauque’s announcement, in 1929 in collaboration with H. L. Johnst’on, of Ohio State University, that three kinds of oxygen existed instead of one, each variety or isotope having a different weight, stimulated world-wide research on all of the lighter elements, including hydrogen, nitrogen, and carbon, and led ultimately to the identification component of of a new isotope of hydrogen-deuterium, “heavy water”-by Harold C. Urey, of Columbia University. Of equal importance is Professor Giauque’s work with very low temperatures and entropy measurements, of which he is said to have made the most systematic study of anyone in the world. His method of obtaining low temperatures through the use of a magnetic engine has enabled chemists to reach temperatures one hundred times as low as could previously be attained. The Charles Frederick Chandler Foundation was established in 1910 when friends of Professor Chandler presented to the trustees of Columbia University a sum of money, and stipulated that the income was to be used to provide a lecture
by an eminent chemist and also a medal t o be presented to this lecturer in further recognition of his achievements in the chemical field. The previous lecturers and the titles of their lectures are as follows: L. H. Baekeland W. F. Hillebrand
Some Aspects of Industrial Chemistry Our Analytical Chemistry and Its Future The Littlest Things in Chemistry 1920 W. R. Whitney 1921 F. G. Hopkins Newer Aspects of the Nutrition Problem 1922 E. F. Smith Samuel Latham Mitchill-A Father in American Chemistry 1923 R. E . Swain Atmospheric Pollution by Industrial Wastes 1925 E. C. Kendall Influence of the Thyroid Gland on Oxidation in Animal Organism 1926 S. W.Parr The Constitution of Coal-Having Special Reference to the Problems of Carbonization 1927 Moses Gomberg Radicals in Chemistry, Past and Present 1928 J. A. Wilson Chemistry and Leather 1929 Irving Langmuir Electrochemical Interactions of Tungsten, Thorium, Caesium, and Oxygen 1931 James B. Conant Equilibria and Rates of Some Organic Reactions 1932 George 0. Curme, Jr. Synthetic Organic Chemistry in Industry The Stuff of Life 1934 Jacob G . Lipman 1914 1916
Temperatures below 1”Absolute W. F. GIAUQUE Department of Chemistry, University of California, Berkeley, Calif.
HE adiabatic demagnetization method of producing very low temperatures resulted from a series of investigations relating to the third law of thermodynamics. This important natural law enables us to determine the conditions of chemical equilibrium from calorimetric data alone, and the practical advantages and economy which result are well known. The third law of thermodynamics1 (26)states that all substances in the perfect crystalline state are without entropy a t the absolute zero of temperature. Thus if the absolute zero be taken as a limit of integration, the entropy of a substance may be evaluated by means of the expression,
s
=AT$
Principally for this reason, a number of chemical laboratories are actively engaged in low-temperature calorimetric investigations. However the absolute zero of temperature cannot be attained and extrapolation is unavoidable in evaluating entropy by means of Equation 1. Until some twelve years ago such extrapolations were simply and somewhat too confidently based on the assumption that no appreciable calorimetric effects occurred in the temperature region below 1’ absolute. In 1924 Nelson W. Taylor and the writer collaborated in conducting a seminar on magnetism a t the University of California. I n the course of this seminar the writer presented a thermodynamic treatment of magnetic phenomena, and in considering certain available magnetic data it became evident that magnetic fields could remove large amounts of entropy
dT
where C , = heat capacity T = absolute temperature 1 A discussion of the historical development of the third law of thermodynamics leading to the accepted statement of Lewis and Gibson is given by Lewis and Randall.
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