N. N. Schiller’s Principle*)

By the end of the nineteenth century, thermodynamics, thanks to the work of the outstanding physicists of the age, constituted a fully and comprehensively developed system of scientific knowledge. However, the Kiev professor Nikolai Nikolaevich Schiller (1848–1910) found here a new position that had not been disclosed by its predecessors. In the work “Experimental Data and Definitions Lying at the Foundation of the Second Law of Thermodynamics,” published in 1900, he expressed the following proposition, or principle**): “It is not possible to lower or raise continuously the temperature of a body by means of closed adiabatic circular processes.” This proposition must be regarded as a consequence of the second law of thermodynamics; this is easy to see by taking the latter, for example, in the following formulation: it is impossible to construct an engine which, as a result of its action, would produce positive work exclusively at the expense of the cooling of one body, without any other changes in the bodies. Nine years later (1909) the same

) A similar letter to the editor was also sent by N. B. Berger.
) N. N. Schiller, ZhRFKhO*, XXXII, 37 (1900).

This proposition was developed in the works of C. Carathéodory and entered science under his name). For greater persuasiveness, let us recall the generally accepted formulation of Carathéodory’s principle: “There exist states of a thermally homogeneous system which cannot be reached, starting from a given state, by means of an adiabatic process”*). Both formulations—Schiller’s and Carathéodory’s—are, as is not hard to see, equivalent, but the first of them was published nine years earlier. In the history of science it is necessary to correct the error that has been made and henceforth to call the consequence of the second law of thermodynamics set forth above Schiller’s principle. It is not difficult to show that, taking Schiller’s principle as the starting point, one can arrive at the second law of thermodynamics.

V. P. Rusakov

) Math. Ann., LXVII, 355 (1909).
) M. A. Leontovich, Introduction to Thermodynamics*, 49, 1951.