Clairaut, Alex Claude (b 1713, making him 18 at the time of the reception of the paper in 1731), "Sur les Courbes que l'ou forme en coupant une surface courbe quelconque, par un plan donne de position", pp 680-694. ("...on solid analytic geometry, a pioneering study of the differential geometry of space curves"--Parkinson, Breakthroughs, p. 149). Bound in: Histoire de l' Academie Royale des Sciences. Annee M. DCCXXXI. Avec le memoires de mathematique & de physique, pour la meme annee. Amsterdam by Pierre Mortier, 1735, 17x10cm., viii, 155pp; plus the Memoires section, pp 1-316 in this volume, and pp 317-737, with 40 folding plates. Bound in full leather, with raised bands. Lovely copies, very fresh and clean. Two volumes; Very Good condition. $450

In the first section, the Histoire contains a review of the recent advances in the sciences (physics, math, geography, geology, biology, “Sur Quelques Experiences de l'Aiman”, “Sur le Nouveau Thermometre”, “Observations de Physique Generale”, “Sur une Nouvelle Espece de Vegetation Metalliques), and then proceeds to the Memoires (scientific contributions section) including:
Clairaut, Alex Claude, "Nouvelle Maniere de trouver les formules des centres de gravite", pp 226-231. (In his letters Clairut states "Here is a new way of finding the formulas of the centers of gravity that I read there is hardly at the Academy I do not give it to you as a new way of having the centers of gravity, for it is not one, but only as a new way of having the formulas already found."

Mairan, “Observations de quelques Aurores Boreales...”, pp 531-545. (This is areport supplement to an entire volume published on thi ssame topic, one of the earliest of its kind, offered elsewhere on this blog under Mairan's name. It was published as volume III of this set for the Memoires of 1731, and stands complete in itself.)
Couplet, “Recherches sur la Construction des Combles de Charpentier”, p 999-102;
Petit, “Dissertations sur la maniere le Sang dans les Hemorragies...”, pp 122-146;
de Maupertius, “Experiences sur les Scorpions”, pp 317-326
d'Onzembray, “ Machine pour coonoitre sur Mer l'Angle de la Lgine du Vent et de la Quille du Vaisseau...” pp 335-340 (with plate!);
Maupertius, “Sur la separation des Intetermindes dans les Equations differnetielles”, pp 147-157;
Maupertius, “Balistique arithmetique”, pp 419-422;
Maupertius, “Probleme Astronomique”, pp 652-655;
de la Condamine, “Sur une nouvelle Maniere de considerer les Sections Coniques”, pp 340-35.

Condamine, “ Sur une nouvelleespece de Vegetation Metaliiques” (with a glorious plate), pp 655-680;
Pitot, “Methode d'Analytique de tracer les Lignescorrespondentes ou des Minutes aux grande Meridiennes”, pp 519-531;
Nicole, “ Sur les Sections Coniques”, pp 157-176.