This was the Observatory noticed by Mr. Lalande, when (in his _Astronomie_, published in 1792,) he made this remark, treating of the numerous Observatories in different parts of the world—“In America, I know of no Observatory but that of Mr. Rittenhouse at Philadelphia.” The Observatory at Norriton, mentioned in the text, was a temporary erection; and was disused on his removal to Philadelphia, soon after. The one put up in the State-House Gardens in that city on the same occasion, was likewise a temporary edifice, constructed of wood. ----- 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,