HELMHOLTZ, Hermann.

Die Thermodynamik chemischer Vörgange. Offprint from: Sitzungsberichte der Königlichen Akademie der Wissenschaften zu Berlin, 1882. [With:] Zur Thermodynamik chemischer Vörgange. Zweiter Beitrag. Offprint from: ibid., 27 July 1882. [With:] Zur Thermodynamik chemischer Vörgange. Dritter Beitrag. Offprint from: ibid., 31 May, 1883.

Berlin: Akademie der Wissenschaften, 1882-1883.

First edition, extremely rare author’s presentation offprints, of all three parts of one of the founding paper of chemical thermodynamics, along with Josiah Willard Gibbs’s 1876 paper ‘On the Equilibrium of Heterogeneous Substances.’ In these papers, Helmholtz introduced the concept of ‘free energy’ and proved the ‘Gibbs-Helmholtz equation’ which he used to demonstrate that free energy – not heat production – was the driver of spontaneous change in isothermal chemical reactions, thereby overthrowing the previously accepted ‘Thomsen-Berthelot principle.’ Although Gibbs introduced similar ideas, he did not state the equation explicitly, nor did he explore its chemical significance. “Helmholtz’s research in physical chemistry culminated in his 1882 memoir, ‘Die Thermodynamik chemischer Vörgange.’ Thermochemistry, especially that of Thomsen and Berthelot, assumed that the heat evolved in reactions is a direct measure of the chemical affinities at work. The occurrence of spontaneous, endothermic reactions had always presented an anomaly in this tradition, for such reactions seemed to act against the forces of chemical affinity. In 1882 Helmholtz distinguished between ‘bound’ and ‘free’ energy in reactions. The former is the portion of the total energy which, in accordance with the entropy principle, is obtainable only as heat; the latter is that which can be freely converted to other forms of energy. From Clausius’s equations Helmholtz derived the ‘Gibbs-Helmholtz equation,’ [which shows that] the free energy, not the total energy change measured by the evolution of heat, determines the direction of any reaction” (DSB). Hence while “Helmholtz was neither the sole nor the most important contributor” to theoretical chemistry, “his thermodynamic theory of 1882–1883 was the pioneering work on which much of the new theoretical chemistry rested” (Kragh, p. 406). No copies in auction records. OCLC lists Institut de France, Paris and University of Strasbourg (first part only), and University of Bern (all three parts); no copies in US.

Provenance: Robert Helmholtz (signature on front wrapper of first part, ‘an seinem Sohn R. H.’ written on front wrapper of third part (probably in Robert’s hand), following printed statement ‘Ūberreicht vom Verfasser’). Robert studied at Heidelberg (with Bunsen) and then at Berlin (with Kirchhoff and his father). In 1885 he was awarded a doctorate at Berlin with a thesis on steam and cloud solutions. Robert was disabled and always in poor health, and died at a young age in 1889.

“Mid-nineteenth-century chemistry was almost a purely experimental and classificatory science. In contrast to physics, it largely lacked theoretical foundations and showed little progress in supplying such foundations. Nearly all chemists merely collected data and analysed specific compounds – an empiricist trend reinforced by the emergence in the 1830s of the powerful new sub-discipline of organic chemistry … Nonetheless, some progress had been made, particularly in the fields of chemical equilibrium and the rates of reaction, electrochemistry, and thermochemistry. The theoretical foundation for much of this work was the concept of ‘chemical force’, or ‘affinity’, the nature of which was, however, obscure. It was at first widely assumed that the affinity of chemical substances would find its explanation in terms of gravitational or electrical forces, or perhaps by means of mechanical models of molecules, yet nothing came of these speculations. Then, with the establishment of the principle of energy conservation around 1850, the heat evolved in chemical processes seemed to offer a quantitative measure of affinity and to provide a theoretical basis for chemical change. Chemists applied the thermal theory of affinity to chemical reactions and used it to study chemical equilibria and electrochemical processes. For these processes it was generally assumed that the electrical heat produced by the electromotive force of the cell equalled the chemical heat, in which case electrochemistry could presumably be understood in terms of thermochemistry.

“According to classical thermochemistry, as founded by Julius Thomsen and Marcellin Berthelot, the heat evolved in a chemical reaction was the true measure of its affinity. The theory rested on the Thomsen-Berthelot principle that all chemical changes were accompanied by heat production and that the actual process which occurred was the one in which the most heat was produced. This principle, formulated in slightly different versions by Thomsen in 1854 and by Berthelot in 1864, became the controversial foundation of a research program that lasted for two decades. It was criticized from the start on theoretical and empirical grounds; by 1880, it was widely recognized that the thermal theory of affinity needed replacement. Its successor, as physicists more than chemists recognized, would have to rely on the second law of thermodynamics. Although this law, along with the associated concept of entropy, had been introduced in the 1850s, it had diffused only slowly to chemistry. The new theory, as it emerged during the 1880s, transformed the methodology of theoretical chemistry without constituting a revolutionary break with its past …

“The transformation of chemistry from a largely static and experimental into a dynamic and theoretical science was produced not by run-of-the-mill chemists but by physicists or chemists with a strong background in physics. Hermann von Helmholtz was one such important figure in that transformation; others were Gibbs, Ostwald, August Horstmann, Svante Arrhenius, and Jacobus Henricus van’t Hoff. Although Helmholtz was not a chemist, his contributions to the fields of electrochemistry and chemical thermodynamics secured him a distinguished place in the history of chemistry. That reputation rested, above all, on his thermodynamic explanation (in 1882) of chemical changes, an explanation that provided chemistry with a solid theoretical foundation. Building on earlier insights gained by himself and other scientists, Helmholtz proved that affinity was not given by the heat evolved in a chemical reaction, but rather by the maximum work produced when the reaction was carried out reversibly. Characteristically, Helmholtz’s demonstration was the result of abstract physical reasoning and not chemical experimentation. His work of 1882-83 was convincing evidence that advanced physical theory had a fruitful role to play even in the traditionally empirical science of chemistry. Although organic chemists continued to distrust the increasing mathematization of chemistry, by 1890 theoretical chemistry had undeniably evolved into an important and useful sub-discipline …

“Helmholtz’s inspiration to develop a chemical thermodynamics did not issue from the works of his predecessors in the field, but rather from his own work in electrochemistry. In 1882 he stated that his theory of chemical energy was inspired by his earlier work on the connection between chemical changes and electromotive forces. He did not mention Thomsen or Berthelot explicitly, but he did refer to the thermal theory of affinity as ‘the older view, which I myself defended in my earlier works.’ This view, he now argued, had only limited validity. Instead of focusing on heat alone, one should distinguish between a part of the energy that appeared only as heat and a part that could be freely converted into other kinds of work. This latter part Helmholtz called ‘free energy’ … Helmholtz wrote: ‘it would then be the value of the free energy, not that of the total energy resulting from heat production, which determines in which sense the chemical affinity can be active.’ Furthermore, Helmholtz distinguished between what he called ‘ordered’ and ‘disordered’ motions, the latter being processes in which ‘the motion of each individual particle does not necessarily have any similarity at all to the motions of its neighbours.’ In this vague sense, he sought to ‘describe the amount of entropy as the measure of disorder.’ Although this sounds like a definition of Ludwig Boltzmann’s probabilistic theory of entropy, it was not. Helmholtz’s thermodynamics remained solidly based on Clausius’s mechanical theory, even though Boltzmann in 1884 cited ‘famous scientists, such as Helmholtz’ in support of his theory. The importance of Helmholtz’s 1882 memoir derived from the concept of free energy and its use by means of [an] equation. This equation, known today as the ‘Gibbs-Helmholtz equation’, became the cornerstone of chemical thermodynamics. Although corresponding results had previously been found or anticipated by other scientists, … none of these physicists explored the chemical significance of their functions. Moreover, the Gibbs-Helmholtz equation, as is well known, was not established by Gibbs, who only discussed what he called ‘Helmholtz’s equation’ in 1887 … Finally, later in 1882 and again in 1883 Helmholtz extended his approach to chemical thermodynamics. He applied his theory to a number of chemical problems, including electrochemistry and the calculation of heats of dilution, and found the theory’s predictions to agree well with measurements. By now aware of the works of his predecessors, he gave full credit to the earlier findings of Rayleigh, Massieu and Gibbs …

“Helmholtz’s chemical thermodynamics and the related work of Gibbs, Duhem, van’t Hoff and others signified the death of classical thermochemistry. Although the limited validity of the Thomsen-Berthelot principle had now been clearly demonstrated, classical thermochemists, such as Berthelot, continued to maintain the principle for several years and hesitated to give up the thermal theory of affinity. As for Helmholtz, he did not further purse his thermodynamic researches of 1882-83. Instead he used this research as an important starting point for his work on monocyclic systems and the principle of least action. In 1887 he briefly returned to chemistry: in an experimental examination of the electrolysis of water he confirmed the predictions of his thermodynamic theory of 1882. Around the same time Helmholtz contemplated bringing his writings on chemical thermodynamics into a more definite and broader form: he began writing a manuscript entitled ‘Thermodynamische Betrachtungen über chemische Vorgänge’; it remained unfinished. Although Helmholtz did no further research in chemical thermodynamics, he did disseminate the theory in a coherent and instructive manner through his regular lectures at the University of Berlin. There he presented a full account of the concept of free energy and its use in chemical and galvanic processes” (Kragh, pp. 401-423)

Kragh, ‘Between Physics and Chemistry: Helmholtz’s Route to a Theory of Chemical Thermodynamics’, in: Hermann von Helmholtz and the Foundations of Nineteenth-Century Science (Cahan, ed.), 1993.

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Three vols., 8vo (260 x 181 mm), pp. [1-2] 3-20; 12; 19 [1]. Original printed wrappers (generally a little worn and soiled, those of the second part chipped at the edges, with outer corners broken off blank rear wrapper).

Item #5192

Price: $32,000.00