The Introduction to 0 0 DUNCAN Chemical Warfare Seruice, Thermodynamics1 Edgewood Arsenal, Maryland MaeRAE
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T SOMETIMES happens in the development of the sclences that subjects are a t first presented in such a way that they seem to have little relation to the other parts of the science to which they belong or to that science as a whole. This has resulted in delay in the acceptance of these subjects and in continued difficulty to both teacher and student until better methods of presentation have been devised. There is perhaps no better example of such a case than one in the field of mathematics given by J. Willard Gibbs. No knowledge of mathematics is xequired to understand his analysis of the difficulty in this case and the nature of the remedy which he offered in his pamphlet on "Vector Analysis.'' In defending this pamphlet"aainst the criticisms of the quaternionists, he began stating with great certainty that the ''&'st duty of the physical Vector analyst qua physical vector analyst . . . is to present the subject in such a form as to be mosteasily acquired, and most Iisefu1 when acquired'" This was in to a question by Mr. McAulay. He then quoted him as follows: Quaternions differin an important respect from other branches of mathematics that are studied by mathematicians after they have in the course of years of hard labor laid the foundation of all their future work. I n nearly all cases these branches are very properly so called. They each grow out of a definite spot of the main tree of mathematics, and derive their sustenance from the sap of the trunk as a whole. But not so with quaternions. T o let these grow in the brain of a mathematician, he must start from the seed as with the rest of his mathematics regarded as a whole. He cannot graft them on his already flourishing tree, for they will die there. They are independent plants that require separate sowing and the consequent careful tending.
He then went on to say:
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Can we wander that mathematicians, physicists, astronomers, and geometers feel some doubt as t o the value or necessity of something so separate from all other branches of learning? Can that be a natural treatment of the subject which has no relations t o any other method, and as one might suppose from reading some treatises, has only occured t o a single man? Or, a t best, is i t not discouraging t o he told that in order t o use the quaternionic method, one must give up the progress which he has already made in pursuit of his favorite science, and go back t o the beginning and start anew on a parallel course? I believe, however, that if what I have auoted is true of vector methods, i t is because there is something f;ndamentally wrong in the presentation of thesubject.. . . If I wished toattract the student of any of these sciences t o an for vectors, I tell him that the.fundamental notions of this algehra were exactly those with which he was daily conversant.. .
Gibbs expressed these views some 15 years after the publication of the last of his three great papers on thermodynamics. Yet it did not seem to occur to him that what he said of quaternions and mathematics applied equally well to thermodynamics and physics. How different the history of science might have been if he had practiced, with respect to thermodynamics and physics. the principles of presentation which he thus set forth 15 years later in connection with vector analysis and mathematics! Theearly history of the presentation of thermodynamics as it actually was has been given by Lewis and Randall? The second law of thermodynamics, which is known also as the law of the dissipation or degradation of energy or the law of the increase of entropy, was developed almost simultsneously with the first law through the fundamental work of Carnot, Clausius, and Kelvin. But it met with a different fate, for i t seemed in n o recognizable way t o accord with existing thought and prejudice. The various laws of conswation had been foreshadowed long before their acceptance into the body of scientific thought. The secondlaw cameas a new thing, alien to traditional thought, with far-reaching implications in general cosmology. Because the second law seemed alien t o the intuition, and even abhorrent t o the philosophy of,the times, many attempts were made t o fiqd exceptions t o this law, and thus t o disprove its universal validity. But such attempts have served rather t o convince the incredulous, and t o establish the second law of thermodynamics as one of the foundations of modern science. I n this pracesswehave becamereconciled toitsphilosophicalimplications. or have learned to interpret them t o our satisfaction, we have learned its limitations. or better. we have learned to state the law in auch a form that these limitations appear no longer to exist; and eqwcially wc h a w lcnrnerl i t > correlation with other filmiliar concept
