The province of New-York passed a legislative act on this subject, in the year 1762; and the New-Jersey Assembly enacted a corresponding law, in 1764. Five commissioners—namely, John Stevens, James Parker, Henry Cuyler, William Donaldson, and Walter Rutherford—were appointed on this business, for the two provinces: their report was passed upon, by both; and it was confirmed by the King in council, the 1st of September, 1773. It is understood, that the division-line between East and West-Jersey remained unsettled, so late as the year 1789. But it nevertheless appears, that the territorial boundary between New-York and New-Jersey was fixed by Mr. Rittenhouse, forty-four years ago.
A recurrence shall now be had to a date anterior to our Philosopher’s employment in the transaction just mentioned.—Within the two years preceding that period, two objects of much importance to astronomical science, claimed a large share of the public attention, in this country: One of them, especially, had already actually engaged the investigations of the ablest astronomers of the other hemisphere, as well as our own; preparatory to the then approaching event, to which those researches were directed. The result of the expectations excited by both of those objects proved, on their final completion, highly honourable to the fame of Mr. Rittenhouse.
The first of these, in the order of time, was our Astronomer’s newly-projected Orrery; a general but concise description of which, was communicated by his friend, the Rev. Dr. Smith, to the Philosophical Society, on the 21st of March, 1768. Of this fine and eminently useful piece of mechanism, more particular mention shall be made in the sequel.
The other circumstance, just referred to, was the then approaching Transit of Venus over the Sun’s disk; an event which was to take place on the 3d day of June, 1769: And of Mr. Rittenhouse’s participation in the arduous labours of the astronomical world, on that very interesting occasion, the following narrative will furnish some account.
The American Philosophical Society, in their meeting on the 7th of January, 1769, had appointed the following gentlemen to observe that rare phænomenon,[[108]] as it was aptly styled by Dr. Smith; namely, the. Rev. Mr. (afterwards Dr.) John Ewing, Mr. Thomas Prior, Joseph Shippen, jun. Esq., Hugh Williamson, M. D., the Rev. Dr. Smith, Mr. David Rittenhouse, John Lukens, Esq. and Messrs. James Alexander, Owen Biddle, James Pearson, John Sellers, Charles Thomson, and William Poole. The gentlemen thus nominated were distributed into three committees, for the purpose of making separate observations at three several places; these were, the city of Philadelphia, Mr. Rittenhouse’s residence, in Norriton, and the Light-House near Cape Henlopen, on Delaware Bay. Dr. Ewing, an able mathematician and very respectable astronomer, had the principal direction of the Observatory in the City, which was erected on this occasion in the State-house Gardens; and Mr. O. Biddle, a person of much ingenuity, had the charge of superintending the observations at Cape Henlopen. Associated with Mr. Rittenhouse, on the Norriton committee, were the Rev. Dr. Smith, provost of the College of Philadelphia, well known as an astronomer and eminently skilled in the mathematics; Mr. Lukens, then surveyor-general of Pennsylvania, who possessed considerable abilities in the same departments of science; and Mr. Sellers, a respectable member of the provincial legislature, for the county of Chester. The Rev. Mr. Barton, with some other gentlemen of ingenuity and talents, voluntarily attended at Norriton, on this occasion; and rendered such assistance as they could, to the committee.
As the time approached near, when this extraordinary and almost unprecedented[[109]] astronomical phænomenon was to manifest itself, the public expectation and anxiety, which were before considerable, became greatly heightened. The ignorant—and those, generally, unacquainted with the nature of the looked-for event,—hearing much every where said on the subject, and seeing the preparations making for the occasion, had their curiosity wonderfully excited. To scientific men, the inestimable value of the approaching phænomenon suggested very different sensations. “Its importance to the interests of Astronomy and Navigation, had,” as Dr. Ewing observed at the time, “justly drawn the attention of every civilized nation in the world.” An accurate ascertainment of the Sun’s Parallax,—an important. and fundamental article in Astronomy, was a desideratum not yet obtained. Only two Transits of Venus over the Sun, had been observed, prior to the 3d of June, 1769, since the creation of the world; and of these, the first alone was seen but by two persons:[[110]] Yet, as the learned gentleman just quoted has remarked,—“the Transits of Venus, alone, afford an opportunity of determining this problem” (the settling the Parallax of the Sun,) “with sufficient certainty: and these,[these,]” he adds, “happen so seldom, that there cannot be more than two in one century, and in some centuries none at all.”
To an object, then, of such vast importance to science, were proportioned the expectations of our Observers. But they could not fail to experience, at the same time, in common with their astronomical brethren in other parts of the world, a large portion of anxious apprehensions, lest a cloudy day—nay, even a solitary passing cloud,—should baffle entirely their exalted hopes, and destroy all the fruits of their arduous labours! Yet such an occurrence, as one or the other of these events, was evidently within the calculations of a probable incident.
Mr. Rittenhouse participated largely in these blended hopes and fears. He had, for some time before, been laboriously employed in making the requisite preparatory observations and calculations: and, as Norriton was now rendered eminently conspicuous, by being fixed on as a principal site for observing the very interesting phænomenon so near at hand, he had been assiduously engaged, at the same time, in preparing and furnishing an Observatory at that place, suitable for the occasion. This he began to erect early in November, 1768,—“agreeably,” to use his own words, “to the resolutions of the American Philosophical Society;” but, through various disappointments from workmen and weather, he was not enabled to complete it till the middle of April, 1769.[[111]]
The Norriton Observatory was commodiously situated near Mr. Rittenhouse’s mansion, on a pretty elevated piece of ground, commanding a good range of horizontal view. This temporary edifice was as well adapted to the purpose for which it was chiefly designed, as the nature of the materials of which it was constructed, and other circumstances, would permit. Some monies had been previously appropriated by the Philosophical Society, towards defraying the expenses necessarily incident to this occasion, at the three several places of observation: but the funds of the society, at their disposal for such purposes, were very limited; and it is believed that the quota of these funds assigned for the expenditures actually incurred for making the observations of the transit, at Norriton, was quite inconsiderable in its amount.
In order that ample justice may be done to the merits of Mr. Rittenhouse, for all the preparatory arrangements made by him on this occasion, the reader is here presented with an extract from Dr. Smith’s subsequent Report, to the Philosophical Society, of the proceedings of the Norriton Committee, and made in their behalf.—“I am persuaded” says the doctor, “that the dependance which the learned world may place on any particular Transit-Account, will be in proportion to the previous and subsequent care, which is found to have been taken in a series of accurate and well conducted observations, for ascertaining the going of the time-pieces, and fixing the latitude and longitude of the place of observations, &c. And I am the more desirous to be particular in these points, in order to do justice to Mr. Rittenhouse, one of the committee; to whose extraordinary skill and diligence is owing whatever advantage may be derived, in these respects, to our observation of the Transit itself.”—“Our great discouragement at our first appointment,” continues the learned reporter, “was the want of proper apparatus, especially good Telescopes with Micrometers. The generosity of our Provincial Assembly soon removed a great part of this discouragement, not only by their vote to purchase one of the best reflecting Telescopes, with a Dollond’s micrometer;[[112]] but likewise by their subsequent donation of one hundred pounds,” (this was in sterling money, = $444) “for erecting Observatories and defraying other incidental expences.[[113]] It was forseen, that on the arrival of the Telescope, added to such private ones as might be procured in the city, together with fitting up the instruments belonging to the honourable the Proprietaries of the province—viz. the equal Altitude and Transit Instruments and the large astronomical Sector,—nothing would be wanted for the city Observatory in the State-House Square, but a good Time-piece, which was easily to be procured. We remained, however, still at a loss, how to furnish the Norriton Observatory:[[114]] But even this difficulty gradually vanished.”