Recherches sur le Dimorphisme WITH Note sur un travail de M. Laurent intitulé: Sur l'isomorphisme et sur les types cristallins in Annales de Chimie et de Physique, 3rd Series, Vol. 23, 1848, pp. 267-294; pp. 294-295

Paris: Victor Masson, 1848. 1st Edition. HANDSOMELY BOUND OF PASTEUR'S 1st FULL EXPOSITION OF HIS REVOLUTIONARY DISCOVERY OF MOLECULAR ASSYMETRY. "Pasteur's discovery counts among the most important advances in chemistry and constitutes the foundation of stereochemistry" ("Citation for Chemical Breakthrough Awards: Choosing Pasteur's Award-Winning Publication" in Bull. Hist. Chem., 38, 2013). Note that we separately offer Pasteur's brief ANNOUNCEMENT of his discovery earlier in 1848 and in Comptes Rendus.

Pasteur's discovery was ‘announced' in the same year in a four page publication of the same title, "Recherches sur le dimorphisme" in Comptes Rendus. Note that we separately offer that announcement. Technically, the announcement, though short, is more highly valued, but with respect to substance, this offering, the Annales de Chimie et de Physique publication, is Pasteur's first full treatment of his discovery as well as his first published paper (the Comptes publication being regarded as only an ‘announcement'). "

Obviously prepared in part by the ideas of Delafosse and Laurent, Pasteur became convinced that the molecular asymmetry of optically active liquids ought to find expression in an asymmetry or hemihedrism in their crystalline form. In may 1848 - having published several related papers on isomorphism and dimorphism in various compounds - Pasteur announced the discovery of small hemihedral facets on the crystals of all nineteen tartrate compounds he had studied. In all of them the hemihedral facets inclined in the same direction, and the direction of optical activity was the same. In the optically inactive paratartrates Pasteur expected to find perfectly symmetrical crystals.

"This expectation was confirmed with the notable exception of the sodium-ammonium paratartrate on which Mitscherlich's claims specifically rested. At first disappointed when he found hemihedrism in these crystals, Pasteur soon noticed that certain crystals inclined to the right, others to the left. Pasteur meticulously separated them by hand, dissolved them, and found that solutions of the right-handed crystals rotated the plane of polarized light in one direction while solutions of the left-handed crystals rotated it in the opposite direction to approximately the same degree. When equal weights of the two kinds of crystals were dissolved separately and then combined, the result was an optically inactive sodium-ammonium paratartrate.

"Similar results were obtained with the acids from which the sodium-ammonium salts had been derived. Right-handed salts gave a right-handed acid identical to ordinary tartaric acid. Left-handed salts gave a hitherto unknown acid identical to tartaric acid expect for the left-handed direction of both its hemihedrism and optical activity. Combinations of equal weights of the left-handed and right-handed acids yielded in acid identical to racemic or paratartaric acid. Pasteur now concluded that the optical inactivity of paratartaric acid (and hence of its derivatives) resulted from its being a combination of two optically active acids that were mirror images of each other, the separate optical activities of which of each other, the separate optical activities of which, in opposite directions, compensated for or canceled each other" (Dictionary of Scientific Biography, Vol. 10 pp. 357-358).

ALSO INCLUDED: Among other important chemical papers, the volume includes Gay-Lussac's Mémoire sur L'Eau Régale, pp. 203-229. CONDITION & DETAILS: Paris: Victor Masson. (8.25 x 5.5 inches; 206 x 138mm). Bears one small number stamp on the rear of the title page and one small circular stamp on the final page. [2], 512, [4]. 4 plates. Handsomely rebound in half-calf over marbled paper boards, gently scuffed at the edges for an ‘aged' effect by the conservator; 4 gilt-ruled and tooled bands at the spine; gilt-lettered black morocco spine label. Tight and very solid; bright and very clean. Occasional toning within. Very good + condition.