The Planetarium invented by Mr. George Graham,[[132]]—and a model of which was improperly retained by Mr. Rowley, its constructor,—had, long before the appearance of Mr. Rittenhouse’s machine, acquired the name of an Orrery; in compliment to Richard Boyle, Earl of Orrery,[[133]] who merely patronized the construction of one, from the artist Rowley’s pirated model. This complimentary appellation of Mr. Graham’s then newly invented Planetarium is said to have been bestowed upon it by Lord Orrery’s friend, Sir Richard Steele:[[134]] and, the name being thus applied to that machine, all those of the nature of Planetaria, subsequently constructed,—however variant in usefulness or design, from the original one bearing the name of an “Orrery,”—were denominated Orreries.[[135]] In compliance, then, with long established usage, Mr. Rittenhouse modestly called his Planetarian-machine, from the first projection of it, an Orrery; although the entire merit, both of the invention and construction, belonged to himself.[[136]]
It is not ascertained, at what time Mr. Rittenhouse first conceived the plan of that extensive, complicated and inestimable Orrery, which he afterwards executed. Probably, he had long thought on the subject, before he publicly announced his design. It is certain, however, that before the beginning of the year 1767, there was some correspondence and some understanding, respecting it, between himself and the Rev. Mr. Barton. It appears in fact, that, prior to that period, Mr. Barton had been fully apprized of his brother-in-law’s desire to carry into effect his meditated design of constructing a complete Orrery, on a plan entirely new; and that some arrangement was previously made, between these gentlemen; by which Mr. Barton undertook to indemnify Mr. Rittenhouse, for such actual expenditures as he should incur in making the machine and his loss of time while employed in the work, not exceeding a stipulated sum; provided he should not be able to dispose of it, when finished, at a price then fixed on. The prudential caution of our young Philosopher (then about thirty-four years of age,) and the public spirit of his friend, grounded on the confidence he had in the artist’s talents and abilities, were alike evinced on this occasion.
The first written communication made by Mr. Rittenhouse to Mr. Barton, on the subject of the Orrery, is contained in a letter under the date of Jan. 28th, 1767: it is in these words:—“I am glad you took the pains to transcribe, and send me, Martin’s Account of Orreries.”[[137]] “Two forms (he says) have principally obtained, the Hemispherical Orrery and the Whole Sphere. But the idea given us by the former, is very unnatural and imperfect. An Orrery, then, adapted to an Armillary Sphere is the only machine that can exhibit a just idea of the true System of the World.”—“But in my opinion,” says Mr. Rittenhouse, “the latter is likewise very unnatural; for, what has a Sphere, consisting of a great number of metaline Circles, to do with the true System of the World? Is there one real, or so much as apparent Circle, in it? (the bodies of the Sun and Planets excepted.) Are they not all merely imaginary lines, contrived for the purpose of calculation? I did not intend to let one of them have a place in my Orrery, except the Zodiac, on which I would have the true latitude and longitude of each planet pointed out by its proper Index.”
“I did not design a Machine, which should give the ignorant in astronomy a just view of the Solar System: but would rather astonish the skilful and curious examiner, by a most accurate correspondence between the situations and motions of our little representatives of the heavenly bodies, and the situations and motions of those bodies, themselves. I would have my Orrery really useful, by making it capable of informing us, truly, of the astronomical phænomena for any particular point of time; which, I do not find that any Orrery yet made, can do.”
“But,” continues Mr. Rittenhouse, “perhaps it may be necessary to comply with the prevailing taste: If so, my plan must be entirely altered;—and this is a matter that must be settled between you and me, before I can proceed. However, I shall send you, in my next, a particular account of my design; such as I would have it, if not limited by the fear of making it too expensive.—A specimen (if I may so call it) of the most curious part of it, though much smaller than that intended for the Orrery, is now in hand, and I hope will soon be finished.”
To this letter Mr. Barton returned the following answer.
“Lancaster, February 21st, 1767.
“Dear Brother,
“I received, a few days ago, yours of the 28th ult.—after it had undergone the torture of some Dutchman’s pocket, which compelled it to force its way through the cover: However, the inside did escape without many fractures; so that I had the pleasure of getting it into my hands in such a condition that I could read it.
“Had I known your distress, at the time you received my letter, I should have sincerely felt for you. I well know the anxiety of an husband, on such occasions, and my heart will ever join in sympathy with him: For you, my feelings would have been doubled, as a husband, as my friend and brother. Glad I am, therefore, that I have no occasion to condole with you, but rather to rejoice; and I most sincerely and affectionately congratulate you, on the escape and recovery of your good girl, and wish you joy of your daughter. I desire to offer my best regards to sister Nelly, for the compliment she intended me, had her child been a boy. Her intention was kind, and I hope to have the continuance of her favourable opinion of me.