The Work and Personality of Walther NernstAuthor(s): Albert EinsteinSource: The Scientific Monthly, Vol. 54, No. 2 (Feb., 1942), pp. 195-196Published by: American Association for the Advancement of ScienceStable URL: http://www.jstor.org/stable/17509 .

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THE PROGRESS OF SCIENCE 195

tagged element or compound in the tis- sues.

Representati-ve of the 13erkeley Radia- tion Laboratory''s accomplishments with tagged atoms are the following: It has been demonstrated that the enzymes of the body break down minerals and other food components much faster than had previously been supposed. For example, calcium is founcd in the nmilk of cows within a few mninutes after the mineral is consumed; formerly it was assumed that this process took days. Long stand- ing theories of plant nutrition have been refuted. Plants can draw food directly from soil partiecles; the food does not need to be dissolved into a solution.

By using radioactive carbon it has

been shown that plants can take up car- bon dioxide without the presence of light. Radioactive strontium, a substi- tute for calcium, has enabled the Berke- ley scientists to study the growth of teeth and bones and the migration of calcium from the mother to the offspring. Many unsolved problems surrounding the me- tabolism of the thyroid gland have been solved by the use of radioactive iodine. The metabolism of single cells is being studied with radioactive salts.

The new laboratory will make possible more extensive studies into the causes of disease such as cancer and leukeinia, and further the development of new treat- ments for various diseases using irradia- tion methods. JosipPHG. HAMILTON

THE WORK AND PERSONALITY OF WALTHER NERNST

I ACCEPT with pleasure the invitation of the editors of this magazine to dedi- cate a few lines to the scientific person- ality of Dr. WAalther Nernst, who died recently. For he was one of the most charac-teristic ancd most interesting schol- ars with whomi I have been closely con- nected during my life. He did not miss any of the conferences on physics in Berlin, and his brief remarks gave evi- dence of a truly amazing scientific in- stinct combined both with a sovereign knowledge of an enormous volume of factual materials, which was always at his comnmand, and with a rare mastery of the experimental nmethods and tricks in which he excelled. Although some- times goodnaturedly smiling at his child- like vanity and self-complacency, we all had for himn not only a sincere admira- tion, but also a personal affection. So long as his egocentric weakness did not enter the pictlure, he exhibited an objec- tivity very rarely founcd, an infallible sense for the essential, and a genuine passion for knowledge of the deep inter- relationls of nature. But for such a pas-

sion his singularly ereative productivity and his important influence on the scien- tific life of the first t:hird of this century would not have been possible.

He ascended from Arrhenius, Ostwald and Van't Hoff, as the last of a dynasty which based their investigations on ther- modynamics, osmotic pressure and ionic theory. Up to 1905 his work was essen- tially restricted to that range of ideas. His theoretical equipment was somewhat elementary, but he mastered it with a rare ingenuity. I refer, for instlance, to the theory of electromotive powers in solutions of locally variable co ncentra- tion, the t:heory of diminution of the solubility by adding a dissolved sub- stance. During this period he invented the witty null-method of determining the dielectric constant of electrically con- dueting bodies by means of Wheatstone 's Bridge (alternating current, telephone as indicator, compensating capacity in comparison-bridge branches).

This first productive period is largely concerned with improving the methodol- ogy and completing the explorat;ion of a

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196 THE SCIENTIFIC AMONTHLY

field the principles of which had already been known before Nernst. This work led him gradually to a general problem which is characterized by the question: Is it possible to compute from the known energy of the conditions of a system, the useful work which is to be gained by its transition: from one state into another? Nernst realized that a theoretical deter- minlation- of the transition work A from the energy-difference U by means of equations of thermodynamics alone is niot possible. There could be inferred from thermodynamics that, at absolute zero, the temperature of the quantities A ancd U must be equal. But one could not derive A from U for any arbitrary teimi- peratures, even if the energy-values or differences in U were known for all con- ditions. This computation was not pos- sible until there was introduced, with regard to the reaction of these quantities under low temperatures, an assumption which appeared obvious because of its simplicity. This assumption is simply that A becomes temperature-independent under low temperatures. The introduc- tion of this assuLmption as a hypothesis (third main principle of the theory of heat) is Nernst 's greatest contribution to theoretical science. Planck founcd later a solution which is theoretically more satisfactory; namely, the entropy disappears at absolute zero temperature.

From the standpoint of the older ideas onl heat, this third main principle re- quired very strange reactions of bodies under low temperatures. To pass upon the correctness of this principle, the methods of calorimetry under low tem- peratures had to be greatly improved.

The calorimetry of high temnperatures also owes to Nernst considerable prog- ress. Through all these investigations, as well as through many stiiuulating sug- gestions with which his untiring inven- tive genius supplied experimenters in his field, he promuoted the research work of his generation mnost effectively. The be- ginnings of the quantum theory were assisted by the important results of those caloric investigations, and this especially before Bohr's theory of the atom made spectroscopy the most important experi- mental field. Nernst 's standard work, " Theoretical Chemistry, " offers, not only to the student but also to the scholar, an abundance of stimulating ideas; it is theoretically elemientary, but clever, vivid ancd full of intimations of maanifold interrelations. It truly reflects his intellectual characteristics.

Nernst wvas not a one-sided scholar. His sound common sense engaged sue- cessfully in all fields of practical life, and every conversation with him brought something interesting to light. What distinguished him from almost all his fellow-countrymen was his remarkable freedom from prejudices. He was neither a nationalist nor a militarist. He juldged things ancd people almost ex- elusively by their direct success, not by a social or ethical ideal. This was a conse- quence of his freedom from prejudices. At the same time he was interested in literature and had such a sense of humor as is very seldom found with mnen who carry so heavy a load of work. He was an original personality; I have never met any one who resembled him in any essen- tial way. ALBERT EINSTEIN

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