Preface.

“The impossibility of an uncompensated decrease of entropy seems to be reduced to an improbability.”¹) original: "The impossibility of an incompensated decrease of entropy seems to be reduced to an improbability." This quote from Josiah Willard Gibbs highlights the shift from absolute laws to statistical probability in thermodynamics.

When the first part of the gas theory term: Gastheorie (Gas Theory). This refers to the kinetic theory of gases, which explains macroscopic properties like pressure and temperature through the motion of invisible molecules. was printed, I already had a manuscript for this present second and final part almost completely finished, in which the more difficult sections were not addressed. Precisely at that time, however, attacks against the gas theory began to increase. I am now convinced that these attacks are based solely on misunderstandings, and that the role of the gas theory in science is far from being played out. In this book, I will attempt to make clear the abundance of results consistent with experience which van der Waals Johannes Diderik van der Waals (1837–1923), a Dutch physicist famous for his equation of state for gases and liquids. derived from it purely deductively. Even in the most recent times, this theory has again provided clues that could not have been obtained in any other way. From the theory of the ratio of specific heats, Ramsay Sir William Ramsay (1852–1916), the chemist who discovered the noble gases. deduced the atomic weight of argon and thus its place in the system of chemical elements; he subsequently proved this was indeed the correct position through the discovery of neon. Likewise, Smoluchowski Marian Smoluchowski (1872–1917), a pioneer of statistical physics. concluded from the kinetic theory of heat conduction the existence and magnitude of the temperature jump term: Temperatursprung (temperature jump). A phenomenon where a discontinuity in temperature occurs at the interface between a solid surface and a gas under low pressure. during heat conduction in very dilute gases.

It would therefore, in my opinion, be a loss for science if the gas theory, due to the current—

¹) Gibbs, Transactions of the Connecticut Academy, Vol. 3, p. 229, 1875; Ostwald's German edition, p. 198.