Thomas Jefferson Papers

To Thomas Jefferson from Henry Voigt, [before 9 April 1802]

From Henry Voigt

[before 9 April 1802]


When I had your watch before to rectify, although I saw a fault in it at that time, as it was in the construction of the movement, (not a defficiency in workmanship,) & not having sufficient experience of the operation of a movement on that construction, I thought it certainly would answer.—But since I have had it my possession this time, I have been more particular in examining, not only the accuracy of the workmanship, but the principles upon which the striking movement was made.—In this I have now made some alteration, and find the watch to go, since, very regular, and cannot see how it is possible to miss striking now, if it be regularly wound up—

There is a Clock in my possession at present made by Mr Rittenhouse. which has a chime of Bells with tunes, and an orrery, in the Arch of the Dial, of the Seven Planets, moving in their respective Orbits: but not on their Axes.—There are no Satellites.—The Planets move in regular, periodical times, but contentric.—The Sun has likewise a concentic motion only. It shews the equation of time, the Moons Nodes, & the Eliptic, on separate circles, or smaler dials on each corner of the main dial; a description of the whole would be too long; I can only say, it is an excellent piece of workmanship in every respect, and not the worse for the length of time it has been in use, and is now put in the best order. The owner wants to part with her, and thinks it would only suit the Philosophical Society or perhaps yourself, as he wishes it to go into the hands of a Person who is acquainted with Astronomy.

You will pardon me to take the liberty of mentioning to you, that an Instrument has been shewn to me for proving Gun powder invented by Mr Jos Leacock.—I have attended its performance and found it very accurate.—I think it full as good as the Howitzer, if not better—It takes only 16 grains of Powder for a proof, which is a saving of powder,—and time may be saved as four is to one.

I am Sir your Obt Huble Servt

Henry Voigt

PS: The other watch shall be done, as soon, and sent as posibly—


RC (MHi); undated; endorsed by TJ as received 9 Apr. and so recorded in SJL.

YOUR WATCH: see TJ to Voigt, 5 Mch. The CLOCK Voigt describes may be the magnificent tall-case clock constructed by David RITTENHOUSE in the late 1760s for Joseph Potts of Philadelphia. Standing more than nine feet in height, it was owned by Thomas Pryor from 1774 until his death in 1801. Passing through several subsequent owners, the clock is currently in the possession of Drexel University. Voigt may also be describing a similarly elaborate Rittenhouse clock that dates to the early 1780s, which is now owned by the Pennsylvania Hospital. This clock is notable for including the planet Uranus (discovered in 1781) in its orrery, which conforms with the seven planets Voigt mentions in the above letter (William Barton, Memoirs of the Life of David Rittenhouse [Philadelphia, 1813], 203; Brook Hindle, David Rittenhouse [Princeton, 1964], 25–6; Thomas G. Morton, The History of the Pennsylvania Hospital, 1751–1895, rev. ed. [Philadelphia, 1897], 337–9; PMHB description begins Pennsylvania Magazine of History and Biography, 1877– description ends , 56 [July 1932], 237–8; George H. Eckardt, Pennsylvania Clocks and Clockmakers [New York, 1955], 141–2).

Joseph LEACOCK of Philadelphia was a former watchmaker and glass manufacturer who was appointed the city’s inspector of pot and pearl ash in 1790. In 1792 and 1793, he advised TJ on potash manufacturing and also sought his charity (Vol. 24:614, 658–60, 661, 715–16; Vol. 27:510–11, 596). A letter from Leacock to TJ, dated 5 Apr., recorded in SJL as received 9 Apr. with the notation “W.” has not been found.

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