From Johann Wilhelm Abraham Jaeger6
ALS: American Philosophical Society
<Frankfurt-on-Main, December 20, 1777, in French: I have a powder mill with twenty-six mixers, and am planning a new one on the model of an oil mill with perpendicular stone mixers, as in the enclosure.7 Ordinary stone may produce explosions; I experimented with marble and found that it apparently did not. A foreign powder-maker whom I met told me that it is used in all American mills. I want to be certain of this, because of the danger involved, and appeal to you as one of our greatest physicists and mechanics. A word in reply will make me grateful for the rest of my life. I would offer my services to Congress were I not, at the age of sixty and after hard campaigns in 1741–44 that ruined my constitution, precluded from defending the liberty that I treasure.>
6. He signs himself engineer, capt.-lieut. of artillery and intendant of the arsenals of Frankfurt. He and his wife were made citizens of the city in 1758, and four years later he bought the Hutterite publishing house; he composed an atlas of Germany and translated into German a military work by the French authority, Guillaume le Blond. Frankfurter Bürgerbuch. Geschichtliche Mittheilungen über 600 bekannte Frankfurter Familien aus der Zeit vor 1806 (Frankfurt-on-Main, 1897), p. 44; Gesamtverzeichnis des deutschsprachigen Schrifttums 1700–1910 (98 vols. to date, Munich, etc., 1979–), XVII, 238; LXVI, 271.
7. He enclosed a drawing of the mill, which is with the letter.