Memoire sur la nature du Principe qui se combine avec les Metaux pendant leur calcination et qui en augmente le poids [Lavoisier's Easter Memoir] in Histoire de l'Academie Royale des Sciences. Année 1775. Avec les Memoires de Mathématique & de Physique, pour la meme annee. Tires des Registres de cette Academie, 1778, pp. 520-526 [1778 FIRST EDITION, LAVOISIER'S OFFICIAL EASTER MEMOIR ON THE COMPOSITION OF AIR]

Paris: De l'Imprimerie Royale, 1778. 1st Edition. FIRST EDITION, LAVOISIER'S OFFICIAL EASTER MEMOIR ON THE COMPOSITION OF AIR.

In this work, Lavoisier proposed that ordinary air is composed of two different gases, one "highly respirable" (that he named "oxygen") and the other (later named nitrogen) that was unable to support combustion or respiration. This work is commonly referred to as Lavoisier's "Easter Memoir" because he presented an earlier version to the Academy around Easter of 1775; as this is the 1778 revised version, historians regard it as Lavoisier's "official" Easter Memoir (Wikipedia). We offer the 1780 edition separately.

In April, 1778, "Lavoisier read for a second time the memoir in which he had originally demonstrated, in April 1775, that mercury precipitate reduced without charcoal disengages not fixed air, but the ‘air itself entire', or ‘the purest portion of the air'. He made some revisions in the text that have attracted widespread attention from historians" (Holmes, Lavoisier, 137).

In the time between 1775 and 1778, Lavoisier repeated some of performed some new experiments of his own and repeated some of Priestley's. In the 1778 ‘official' version, Lavoisier "altered the language in which he had described that air, calling it now ‘the most salubrious, the most pure portion of the air', and air ‘in an eminently respirable state'. Fastening on to this last phrase, he again referred to the air later in his memoir as ‘eminently respirable air'. At the same time he deleted references to it in the original version as ‘common air', and eliminated the experimental description that it reacted to the nitrous air test in the same manner as common air...

"Historians have tended to treat with suspicion the textual changes Lavoisier made. The implication seems to be that he sought to represent himself as having clearly understood in 1775 that the air released from the mercury calx is a specific portion of the atmosphere when, in fact, he had then still not distinguished it unambiguously from ordinary air. If one couples this suspicion with acceptance of Priestley's charge that Lavoisier had obtained the idea for the experiment from him in the first place, then one creates an image of Lavoisier as one who is known to have had an ‘occasional tendency to allow the work of others to pass as his own'.

"There is, however, no solid evidence that in making these changes he was attempting to rewrite history... His motivation was probably [simple]. By the spring of 1778, when his new theoretical edifice had solidified, the experiments on mercury calx would have come to appear to him as one of the decisive experimental foundations on which he had erected it. Yet when he looked back on the paper which reported these experiments from the vantage point he had since attained, the descriptions of the air he had identified in it would have appeared confused, ambiguous, and inconsistent.

"The embarrassment of allowing such flaws to remain, in what he could now anticipate might someday be regarded as a classic paper, is obvious. Since the paper had yet to appear in the Memoirs of the Academy, chronically two to three years late in publication, he had a convenient opportunity to avoid that outcome" (Holmes).

ALSO INCLUDED: An important paper by P. S. Laplace introducing the concept of the "Coriolis effect" fifty years before Coriolis. Euler had also written about the effect in 1749. "Recherches sur plusieurs points du système du monde" in Mémoires de l'Académie des Sciences Année 1775 pp. 75-182, 1778. This is part one of a two part paper. CONDITION: Paris: De l'Imprimerie Royale. 4to (10.5 x 8.25). 11 folding engraved copperplates. Prior ownership name, 'Bernardi' on front free endpaper. Contemporary full leather binding. Front joint between spine and boards cracking but solid. Handsome wide margins throughout. Slight toning throughout, otherwise bright and very clean. Very good condition.