‎"LAURENT, AUGUSTE. - CLEARING THE CONCEPTS EQUIVALENTS, ATOMS AND MOLECULES.‎
‎Recherches sur les Combinaisons Azotées.‎

‎Paris, Victor Masson, 1846. 8vo. Contemp. hcalf, raised bands, gilt spine. Light wear along edges. Small stamps on verso of titlepage. In: ""Annales de Chimie et de Physique"", Troisieme Series - Tome 18. 512 pp. and 2 folded engraved plates. Laurents paper: pp. 266-298. Somewhat brownspotted.‎

Reference : 45993

‎First printing of this classic work in the history of organic chemistry in which Laurent made clear ""the distinction between equivalents, atoms and molecules, by attaching to these terms meanings similar to those given to them at the present day. Like Avogadro and Ampère, Laurent regarded the molecules of hydrogen, of oxygen, of chlorine, etc., as consisting of two atoms and of forming ""homogenous Compounds"" which could then give rise to ""heterogenous compounds"" by double decomposition -(HH) + (CICI) = (HCI) + (HCI) - as had long before been pointed out by Avogadro.""(Findley ""A Hundred Years of Chemistry"", p. 32.""A founder of modern organic chemistry, Laurent was one of the most important chemists of the nineteenth century. He considered the behavior of matter to be a manifestation of its intimate internal structure, which one cannot determine with certainty but which one has to investigate if one wants to understand. Laurent’s preoccupation was to construct a method that could guide the chemist forward along this path, from facts to their causes. He was the first chemist to intimately associate crystallo-graphic data and chemical studies. Louis Pasteur and Charles Friedel later followed the way.""(DSB).‎