[135]. Besides the Orrery here referred to, as the invention of the celebrated mechanic and watchmaker, Mr. George Graham, a like machine was afterwards contrived by Mr. James Ferguson, an eminent Scotch mechanic and astronomer, and another planetarium of the same kind, by Mr. William Jones, an ingenious mathematical instrument maker, of London. From the planetarium or orrery of Graham, however, as a model, all the modern orreries, prior to Mr. Rittenhouse’s, appear to have been taken. The one constructed by Mr. Rowley is said to be very similar to that invented by Dr. Stephen Hales.
But the idea of a planetarium, somewhat similar to the Rittenhouse-orrery, seems to have been conceived by Huygens, who died in 1695. A collection of this celebrated philosopher’s works was printed at Leyden in the year 1724 and 1728: and in these will be found the description of a planetarium; “a machine” (says Lalande, in speaking of the one contemplated by Huygens,) “which represents, by wheel-work, the revolutions of the planets around the sun and of the moon around the earth, in their durations and natural dimensions; with their excentricities, their inequalities, and their inclinations towards the ecliptic.” See Lalande’s[Lalande’s] Astron.
[136]. Mr. Jefferson remarks, in his Notes on Virginia, that “Mr. Rittenhouse’s model of the planetary system has the plagiary appellation of an Orrery.” This was, undoubtedly, a plagiary name, in its relation to Graham’s Planetarium, of which Lord Orrery was the supposed inventor: but the charge of plagiarism does not properly apply to the same name, when bestowed by Mr. Rittenhouse himself, on the grand machine of his own invention and construction. How improper soever this name may have been in its first application to a planetarium, it has since been generally applied to similar machines; and it has thus acquired an appropriate signification in relation to them. Mr. Rittenhouse did not choose to depart from the appellation in common use, in naming a machine for surpassing, in ingenuity of contrivance, accuracy and utility, any thing of the kind ever before constructed; yet, in all those points of excellence, he was the inventor of that admirable machine, which has been generally denominated, by others, “the Rittenhouse Orrery.”
[138]. See A Compendious System of Natural Philosophy, &c. by J. Rowning, M. A. part iv. chap. 15.
[139]. The Hon. Thomas Penn, of Stoke-Poges, in Buckinghamshire, heretofore one of the Proprietaries of the former province of Pennsylvania. This gentleman was then usually styled, in Pennsylvania, “The Proprietor.”
[140]. This design was, however, finally abandoned.
[141]. One of these valuable clocks, which is of a large size, with an accurate little planetarium attached to its face and placed above the dial-plate,[[141a]] was made for the late Mr. Joseph Potts, of Philadelphia county, who paid for it, as the writer is informed, six hundred and forty dollars. In the spring of the year 1774, it was purchased by the late Mr. Thomas Prior, of Philadelphia; to whom, it is said, general Sir William Howe made an offer of one hundred and twenty guineas for it, shortly before the evacuation of that city, in 1778. It is also said, that Don Joseph de Jaudenes, late minister of Spain to the United States, offered Mr. Prior eight hundred dollars for this clock, with a view of presenting it to his sovereign. Mr. Prior, however, retained it until his death, in the spring of the year 1801: after which, it passed through two other hands, successively, into the possession of Professor Barton, of Philadelphia, whose property it now is.
[141a]. The area of the face of the dial plate is twenty inches square, and the motions and places of the planets of our system are represented on a circular area of eight inches in diameter.
[142]. It appears that Mr. Barton must have transmitted to the honourable Mr. T. Penn, in London, a description of the Orrery, very soon after it was publicly communicated to the Philosophical Society in Philadelphia; for, a letter from Mr. Penn to that gentleman, dated July 22, 1768, contains this remark—“The account you give me of Mr. Rittenhouse’s Orrery, is what I could not have imagined could be executed in Pennsylvania; and I shall be much pleased to see a copper-plate of it, for which I would make that gentleman a present, for his encouragement; or, perhaps he may be induced to bring it hither, and exhibit it, by publicly lecturing on it.”