Heidelberg, C. F. Winter, 1842. 8vo (19.2 x 12.0 cm). 8 pp. Later olive buckram with gilt title and logo of the Chemists' Club on the spine.

First formulation of the law of the conservation of energy, by the German physician and physicist Julius Robert von Mayer (1814-1878), who - also in this paper - calculated the mechanical equivalent of heat. This paper, dated 31sten Mai 1842, "set out Mayer's definitive view on the conservation of energy and established his claim to priority; historically the paper also provides insight into the processes through which Mayer arrived at his theory." (DSB). Mayer started his paper as follows: "Der Zweck ... ist, die Beantwordtung der Frage zu versuchen, was wir unter 'Kraften' zu verstehen haben, und wie sich solche untereinander verhalten". Mayer's paper was published on pages 233-240 in volume 42 of the Annalen der Chemie und Pharmacie, edited byFriedrich Wöhler and Justus Liebig. Volume 42 is her bound together with volume 41, which was published in 1842 as well. Provenance: this copy from the Chemists' Club, New York; with their wacky chemical geezer bookplate on the front pastedown, blind stamp in the lower margin of the second title page of Band XLI, along a stamped number. Inner hinges strengthened with blue linen tape, first title pages somewhat browned. First title with small paper flaw to left margin and strengthened to inner joint. Another Chemists' Club stamp on the front free endpaper recto. The title pages to Band XLII - which contain Mayer's paper, however, are clean. DSB IX, p. 236; PMM 323.