A FAMILY COPY?
Mélanges de physique et de médecine
: chez P. G. Cavelier, libraire, rue S. Jacques, au Lys d’or, 1771
8vo: a6 A–2B8 (+/H6), 200 leaves, pp.  iii–ix  400. Each gathering is signed ‘Tome I’. One engraved plate (platemark 178 x 105mm) bound as a throwout at K3v. Woodcut device on title, head- and tail-pieces in the text.
Leaf 196 x 123.
Bibliography: Wellcome II, 496; Blake 266; Albert Norton and Hurtes 1367; Neu 234; not in Semba and Smets.
An important collection of memoirs, four of which are published here for the first time. The first paper in the volume presents Le Roy’s highly influential theory of evaporation, based on the idea that vapours in the air are analogous to salts in solution. The word ‘precipitation’ in meteorology is a linguistic remnant of Le Roy’s theory, by which he ‘performed an invaluable service to science’ by clearing the way for the important advances in the theory of evaporation made by Dalton and Lavoisier. (See J.B. Gough, DSB 8:255–56.)
Le Roy, an eminent physician and teacher of medicine, was the son of the celebrated horologist, Julien Le Roy. He received his medical training at Montpellier and became a member of the faculty of medicine there after travelling extensively in Italy.
The separate memoirs in the volume are:
1. Mémoire sur l’élévation et la suspension de l’eau dans l’air; et sur la rosée.
2. Mémoire sur l’usage des eaux de Balaruc.
3. Observations sur les eaux de Balaruc.
4. Mémoire sur le méchanisme par lequel l’oeil s’accomode aux differentes distances des objets.
5. Second mémoire sur la vision, considérée relativement aux differentes distances des objets, with a plate.
6. Mémoires sur les fievres aiguës.
7. Reflexions et observations sur le scorbut.
8. Mémoire sur les eaux sulphureuses, contenant le moyen de les imiter parfaitement.
9. Précis sur les eaux minérales.
Items 1, 3 and 4 were first published in the memoirs of the Académie Royale des Sciences 1751, 1752, 1755. Item 9 was first published in Latin as De aquarum mineralium, 1757, 1762. Item 6 was first published as Mémoires et observations de médecine Montpellier,1766. Items 2,5,7 and 8 are published here for the first time.
A second volume was published in 1776 and contained a single work, Du pronostic dans les maladies aigues. The present volume is often catalogued on its own and this copy was probably bound for a member of the author’s family, no doubt before the second volume appeared as there is no volume number on the spine.