CLAUSIUS, R. (RUDOLF). - AVOGADRO'S HYPOTHESIS CONFIRMED AND EVAPORATION EXPLAINED.

Mémoire sur la nature du mouvement appelé CHALEUR. (Extraits par M. Adolphe Wurtz).

Paris, Victor Masson, 1857. 8vo. Contemp. hcalf. Raised bands, gilt spine. A bit rubbed along edges. In: "Annales de Chimie et de Physique", 3ieme Serie, Tome 50. 512 pp. a. 1 folded engraved plate. (Entire volume offered). Clausius' paper: pp. 497-507. Stamp to verso of titlepage. Internally clean.

First French version of this milestone paper on the Kinetic Theory of Gases - "Ueber die Art der Bewegung, welche wir Wärme nennen", 1857 - in which Clausius gives the physical explanation for the evaporation of a liquid and presents the first physical argument in support of Avogadro's hypothesis that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

"In the paper "Ueber die Art der Bewegung, welche wir Wärme nennen.", Rudolf Clausius (1822-1888) established mathematically that the heat in a gas cannot be accounted for exclusively by translational motion of the molecules and asserts that molecules have rotational and vibratiional motion as well as translational motion. He consequently rejects the contentions the the translational kinetic energy is conserved during molecular collisions and that all molecules have equal, constant velocities. His allowancee for differing molecule velocities enables him to offer a new explanation of evaporation, asserting that he molecules able to overcome the attractive forces of the liquid and "escape" to the gaseous state are those with high velocities (and hence high kinetic energies). hence evaporation produces a loss of energy in the liquid and a decreasein temperature."(Parkinson in "Breakthroughs", 1857 C/P).

"This 1857 paper (the paper offered) also marked another importent beginning in physical theory, for it presented the first physical argument in support of Avogadro's hypothesis that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. Clausius argued that if it were assumed that all types of molecules possess the same translational energy at equal temperatures, then, since all gases have the same relationship between pressure, volume, and temperature, they would necessartly contain equal numbers of molecules in equal volumes at the same temperatur and pressure. Avogadro's hypothesis, therefore, found support in the mechanical theory of heat, independently of the usual chemical arguments."(DSB III, p. 307).

The volume contains JOULE'S famous paper "Remarques sur la nature de la chaleur et la constitution des fluides élastiques" (Extraits par M. Verdet). Originally published (1848) 1851. First French version. pp. 381-83.

Order-nr.: 49326