[A32]. Mars appears to be surrounded by a very great and dense atmosphere.
[A33]. Dr. Herschel discovered, in the year 1789, (fourteen years after the delivery of this Oration,) two other satellites of Saturn. These are the innermost of his (now) seven secondary planets.
W. B.
[A34]. In 745, Virgilus, bishop of Saltzburg, having publicly asserted in some of his sermons, that there were antipodes, he was charged with heresy, by Boniface, bishop of Mentz, and cited to appear before the Pope, who recommended the hearing of the cause to Utilo, King of Bohemia, and at the same time wrote to him in favour of Boniface. The event was, the bishop of Saltzburg lost his cause, and was condemned for heresy.
[A35]. It has been shewn, in a preceding note, how much the means of communicating between distant regions, separated by seas, ware facilitated by the discovery and use of the Compass: but those means have been still further and very greatly improved, since the introduction of the use of the Quadrant at sea, especially that called Hadley’s Quadrant.
The true inventor of the reflecting Quadrant was Dr. Robert Hook, a very ingenious English mathematician and philosopher, who died in the year 1702, at the age of sixty-seven years. This instrument, now commonly styled Hadley’s, was afterwards rendered much more complete than Dr. Hook’s invention had made it, by Sir Isaac Newton: but our modern artists, more skilful than those of former times, as Mr. Lalande has observed, have profited of the ideas of the great Newton himself, on the subject; and among the later improvers of the Sea Quadrant, or Octant, is Mr. Hadley, whose name the instrument usually bears.
It would, however, be doing an act of injustice to the memory of an American who possessed an extraordinary genius, to omit, in the course of these memoirs, some notice of his merits in relation to this matter. Mr. Thomas Godfrey, a native of Pennsylvania, is said to have turned his attention to this subject, so early as the year 1730; and in the Transactions of the Royal Society of London, No. 435, will be found, an “Account of Mr. Thomas Godfrey’s Improvement of Davis’s Quadrant transferred to the Mariner’s Bow,” drawn up by James Logan, Esq. formerly of Philadelphia, a gentleman of extensive learning, and a very eminent mathematician, Mr. Godfrey is stated to have “sent the instrument (which he had constructed) to be tried at sea by an acquaintance of his, an ingenious navigator, in a voyage to Jamaica, who shewed it to a captain of a ship there, just going for England; by which means, it came to the knowledge of Mr. Hadley, though perhaps without his being told[told] the name of the real inventor.” [See The American Magazine, for July 1758.] In a letter, dated at Philadelphia the 25th of May, 1732, Mr. Logan, who very ably as well as meritoriously patronized Godfrey, communicated to the celebrated Dr. Edmund Halley a detailed account and description of the improved Sea-Quadrant constructed by that ingenious citizen of America, of which his patron confidently believed him to be the original inventor. On the 28th of June, 1734, a further account of Godfrey’s invention was drawn up by Mr. Logan, and subscribed with his name; which, it is presumed, was also communicated to the Royal Society: and on the 9th of November, in the same year, Mr. Godfrey transmitted an account of it, draughted and signed by himself, to the same learned body. The whole of these interesting letters, with some accompanying observations on the subject, are published in the valuable Magazine just referred to, and in the one for the succeeding month.
In the Transactions of the Royal Society, for the months of October, November and December, 1731, No. 421, is contained a Proposal, by Dr. Edmund Halley, for finding the longitude at sea, within a degree or twenty leagues, &c. In the conclusion of this paper, Dr, Halley, in speaking of John Hadley, Esq. VP.R.S, (“to whom,” as he observes, “we are highly obliged for his having perfected and brought into common use the reflecting telescope,”) says—He “has been pleased to communicate his most ingenious instrument for taking the angles by reflection,” (referring, here, to the Philos. Trans. No. 420;) “it is more than probable that the same may be applied to taking angles at sea, with the desired accuracy.”
In Mr. Logan’s account of Mr. Godfrey’s invention, dated June 28, 1734, he says: “Tis now four years since Thomas Godfrey hit on this improvement; for, his account of it, laid before the (Royal) Society last winter, in which he mentioned two years, was wrote in 1732; and in the same year, 1730, after he was satisfied in this, he applied himself to think of the other, viz. the reflecting instrument, by speculums for a help in the case of longitude, though ’tis also useful in taking altitudes: and one of these, as has been abundantly proved by the maker, and those who had it with them, was taken to sea and there used in observing the latitudes the winter of that year, and brought back again to Philadelphia before the end of February 1730–1, and was in my keeping some months immediately after.”
In Mr, Logan’s prior letter to Dr. Halley (dated May 25, 1732,) he says, that about eighteen months before, Godfrey told him, “he had for some time before been thinking of an instrument for taking the distances of stars by reflecting speculums, which he believed might be of service “at sea;” and that, soon after, Godfrey shewed him an instrument, which he had procured to be made, for the purpose. Thus, the time to which Mr. Logan refers Godfrey’s communication of his improvement to him, would make its date to be about the month of November, 1730.