To Benjamin Franklin from Le Roy, [1781 or after]
From Le Roy
AL: American Philosophical Society
Thursday [1781 or after]2
Accept my Dear Doctor of my best Compliments and Send me word whether you will have a game at Chess This evining. Be So good to Send me for some moments The Volue [Volume] of The Dictionary of Physicks, I lent you, where is the article of The fire Engine.3
Be so good My Dear Doctor to add The courier de LEurope received last.
Addressed: M. Le Dr Franklin
2. The year Mathurin-Jacques Brisson published his Dictionnaire raisonné de physique (3 vols., Paris).
3. The entry on pumps in volume two of the Dictionnaire contained articles on both “pompe à incendie” (fire engine in the modern sense) and “pompe à feu” (or “machine à feu,” the common terms for steam engine).
At the end of 1781, in addition to the public concern about fire prevention (for which see BF to Hartley, Dec. 15), interest in hydraulics was high. In December, Le Roy and the abbé Charles Bossut reported to the Academy of Sciences on a machine that raised water to great heights, invented by Charles-Vincent Vera: Jour. de Paris, Dec. 29, 1781. In October, 1781, the Périer brothers (XXXIV, 175–6n), whose pompes à feu at Chaillot were designed to pump water from the Seine into two reservoirs (an idea proposed by Le Roy), issued a prospectus proposing to pipe this water directly to neighboring houses. BF possessed two copies of their prospectus (“Liste des livres,” Dec. 31, above), which was described in the Jour. de Paris of Nov. 3; see also Jean Bouchary, L’Eau à Paris à la fin du XVIIIe siècle: La Compagnie des Eaux de Paris et l’entreprise de l’Yvette (Paris, 1946), pp. 49–51.