From François Willem de Monchy3
ALS: American Philosophical Society
Rotterdm, the 9 Jan. 1767
I have spoken here with a man to make you a model of an Iceboat, but as it must be made in the proportion of an Inche, or perhaps less to a foot it will cost you about 10 Duc., that is between 4 and 5 guineas, and this is the reason why I ask you first if you will give so much for it, if you like it, I’ll take care it shall be made soon, and send it over directly.4
In your kind letter5 you wrote me that the fire-Engine in York-buildings consumed 4 sh. worth of coals every hour, so it would be about £5 a day, that is £1750 a yaer, and in Dr. Disaguliers6 I find that the Fire-Engine at Griff don’t cost more than £150 a yaer and there fore I believe you have mistaken.
If you would be so good to answer this letter, and the questions I asked you in my first, you would do me a sensible pleasure.7
When I was last in London I bought two microscopes for a Friend, of Mr. Benj. Martin8 in Fleet street, for which I paid him seventeen guineas. He was to send them to Ipswich before I left that place, but did not, and by the last letters from thence, I find the[y] are not yet there. Since my arrival I have wrote to Mr. Martin, Desiring him to send them to me here, but can get no answer. I should there for be obliged to you Sir, if, when you go that way you would be so kind to Speak to Mr. Martin about them and let me know what he says, as he does not care to do it him self, or if it be too much trouble for you to speak to him, be so good as to send your servant, tho a word from you would avail most.
F:W: DE Monchy.
Addressed: To / Dr. B. Franklin at / Mrs. Stevenson in Craven / Street at / London
3. For de Monchy, at this time a medical student at the University of Leyden and later a member of the Batavian Society for Experimental Philosophy, see above, XIII, 484 n.
5. Apparently one of Oct. 23, 1766, not found; see above, XIII, 484.
6. John Theophilus Desaguliers (1683–1744), F.R.S., 1714, was a natural philosopher, experimenter, and popularizer of science, whose important A Course of Experimental Philosophy (2 vols., London, 1734–44) BF knew well. Desaguliers made several improvements in steam engines and evidently worked on one erected to draw water from a coal pit at Griff in Warwickshire. DNB; A. Wolf, A History of Science, Technology, & Philosophy in the 18th Century (2d edit., N.Y., 1961), II, 615.
7. BF’s answer, for which de Monchy thanked him on May 15, 1767, has not been found; see below, p. 149.
8. Benjamin Martin (1704–1782) was an instrument maker, one of whose most successful devices was a pocket microscope; and a writer on scientific subjects, whose Essay on Electricity was known to BF (above, III, 134; VIII, 332). DNB.
9. Solomon de Monchy (1716–1794), a Rotterdam physician and one of the original members and directors of the Batavian Society for Experimental Philosophy; above, XIII, 484 n.
1. This is the first mention of Dr. John (or Jan) Ingenhousz (1730–1799), who figures largely in BF’s later years in England and in France. The details of his early years are far from clear. Born in Breda, a Dutch town 26 miles southeast of Rotterdam, he studied medicine at the University of Leyden, and then returned to his home town to practice, apparently in 1757. His father is said to have been a friend of Sir John Pringle, who after the death of the elder Ingenhousz, persuaded his son to come to Britain to continue his medical studies. Exactly when BF and Ingenhousz met is not clear. In 1768 Pringle chose him to go to Austria to inoculate the imperial family for smallpox, a visit which resulted in his selection as physician to Joseph II and Maria Theresa and which also procured him a handsome pension. It was in his capacity as imperial physician that BF during the Revolutionary War tried to use him to spread American influence in Vienna. DNB.