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and Horsley in opinion, whose conjectures are certainly plausible, and who appear to have considered the matter well.
This work was written originally in Latin, and in no very elegant style. It is translated by Mr. Alexander Campbell, and pretty faithfully done.
The ten engravings with which the history is illustrated are very neatly executed.
everre dim! Anany eyes, year 1786
Art. IX. Affronomy, in Five Books. By Roger Long, D.D.
F.R.S. Master of Pembroke Hall, and Lowndes' Professor of Altronomy and Geometry in the University of Cambridge. 400. .2 Vols. 21 25. (No Bookseller's Name.) 1742, 1764, and 1784. TF we are not mistaken, for we cannot pretend to be positive
I concerning a circumstance which happened so long ago, it was in the year 1730, that Dr. Long first published proposals for printing this treatise of astronomy, of which we are now let down to.give an account in the year 1786-upwards of fifty years afterward! How many eyes, beside the Author's, are since then be. come dim! And how few of his numerous list of subscribers, every one of whom, no doubt, Aattered himself with the pleasure of seeing iwo handsome quarto volumes on astronomy in his library, have lived to see their hopes fulfilled! Out of all that we have either known, read, or heard of among them, two only remain! the Right Hon Brownlow Earl of Exeter, and the Rev.' Dr. Shepherd, Professor of Astronomy and Philosophy in the University of Cambridye! But such, alas! is the issue of most of our prospects in this world!
In 1742' the Docior published his first volume, containing the firt and second books, with a very extensive Introduction; in which he delivers the principles of plane and spherical trigoDometry, the projection of the sphere, and some other matters, wbich are neceffary to be knowo before a learner can enter on the subject of astronomy with pleasure and advantage. In 1764 he published the third book, as a part only of the second voJume. Between this time and that of his death, which hapa pened December 16th, 1770, he finished, and printed off, the fourth book, which completes the scientific part of the work, and a small part of the fifth, containing the history of aftronomy, from the earliest ages, to about the time when he published the former part of his second volume. A short time before he died, he desired Mr. Dunthorne, who was one of his executors, to finih the work. Mr. Dunthorne, we are told, made. a rough draught of the remaining part of it; but being appointed super-intendant of the works of the Bedford-Level Corporation, his avocations became many and unavoidable, so that he had liccle leisure to attend to the Doctor's requelt; and he' Rev. Odt. 5786.
Jeft the work, at his death, in a very imperfect state. Mra Wales, of Christ's Hospital, was then applied to, and prevailed on to revise and corre& Mr. Dunthorne's continuation, and to complete it on the original plan, sketched out, and begun by the Author himself, in that part of the fifth book which had been printed before his death. Such is the history of this long, very Jong, expected work.
The contents of the Introduction have been specified already. In the firft book, the Author treats of the figure and magnitude of the earth; the means and modes of measuring that magnitude; and gives an account of the several attempts which have been made to perform it, and he enumerates the names of the several persons who have made these attempts. He explains the nature and uses of the circles which are imagined to'be described on the terraqueous globe, and alligns their positions with respect to one another. He treats also of the longitudes and latitudes of places, the height of the poles, and the altitude of the equator in different latitudes ; describes the instruments commonly ufed for observing the altitudes of the Sun, Moon, and Stars, and the manher of using them; explains the diurnal and annual motions of the Earth, and their consequences, and also the astronomical and geographical terms which are applied to the inhabitants of different parts of it, on account of their situation with respect to one another, and on account of the diurnal and annual motions. He Mews the difference between the true and apparent levels, the extent of the visible horizon, and the means of measuring it; also the heights of mountains, and the depth of the sea. He gives the general principles of dialing and navigation, the use of the terrestrial globe, maps, &c. and treats of the nature and properties of magnetism, the sea-compass, its variation, dipping, &c. &c.
In the second book Dr. Long treats of the system of the universe; the solar system, its situation and extent; of the planets, their number, order, and situation with respect to the sun, and to each other; their distinction into inferior and superior, primary and secondary; of the zodiac, the ecliptic, its division, and the orbits of the planets; their longitudes and latitudes, both helio. centric and geocentric; their distances from the Sun, their nodes, apsides, limits, and diameters, both real and apparent; of their motions, as well direct as retrograde: of comets, their orbiis and motions : of the obliquity of the ecliptic, proofs of its being variable; the obliquity at different times; and the opinions of several learned men concerning it : of the fixed stars, their nature and uses : of the number of the stars, their magnitudes, and distance from us: of their aberration, their annual parallax, and the cause of their twinkling: of nebulous or cloudy stars, double and variable stars; and the changes which have been ob
erlity of mes of the 'wilight differens Various
Terved in them, their places, &c. : of the constellations, unformed Itars, and an account of the various catalogues which have been made of them in different ages : of the atmaspbere, refractions, and the twilight; its cause, nature, and duration at different times of the year, and in different latitudes : of the di. versity of the seasons, and the cause of it: the doctrine of parallaxes.
In the third book Dr. Long treats, in a more particular man. ner, of the motions of the Sun, Moon, and planets : shews that the motion of the Sun is not uniform, explains the cause of it, and the consequences. He explains also the difference between mean and apparent time; what is meant by the equation of time ; and gives an account of the several means which have been used for measuring time. He treats also of the Moon's motion, as well on its axis as in its orbit; of the inequali. ties of the latter motion, and the caufes of them; and thews that the Moon is a secondary planet, revolving round the Earth. He explains the nature of the Moon's nodes, and apses, and their motions; treats of the inclination of her orbit; of her libration; of her latitude; her parallax, and the methods which have been taken to find it ; of the satellites of Jupiter, their use in finding the longitudes of places, their motions, magnitudes, and the times of their revolution in their respective orbits; of the diameters of their orbits, and their inclinations to the plane of the ecliptic; of the tables which have been made of their motions, their eclipses, their occultations by the body of their primary planet, and the power of telescopes proper for observing them; of the ring of Saturn; his satellices, the times of their revolutions, and the inclinations of their orbits; of the eclipses : of the Sun and Moon, their frequency, restitution, and uses in geography and history : of comets ;, their nature, magnitude, and supposed úses; the appearance of one first predicted by Dr. Halley : of the tranfits of the planet Venus over the Sun's disk; their uses and times of happening : of the solar atmosphere, the at- . mosphere of the planets, and the lunar atmosphere-proofs of the existence of it: of the spots which are observed on the sur. faces of the Sun, Moon, and planets; conjectures concerning their nature and causes-bave been the means of detecting the revolutions of these bodies on their axes; and the times in which these revolutions are performed : of the situation of the solar axis . with respect to the plane of the ecliptic, and the zodiacal light: of the harvest Moon, the horizontal Moon, and the figure of the sky : of epochas, æras, cycles, calenders, and the division of time into weeks, months, and years : of the poetical risings of the stars and planets; and the use of the celestial globe.
The fourth book comprehends physical astronomy; the opi. nions of the ancient philosophers concerning the formation of the
world; the system of Descartes ; Burnet's theory; its refutation by Keil and Woodward ; Woodward's natural history of the earth; Whiston's theory; general error of all these cosmogonifts; Halley's theory of the magnetic needle, and its variations. Of the Newtonian philosophy; general definitions ; the theory of gravitation; the laws of falling bodies, pendulums, projectiles, central forces, &c.; the laws of the Moon's motion ; of the rides, the precession of the equinoxes, and the nutation of the earth's axis. The fillems of Pyrhagoras, Capella, Apollonius, Ptolemy, and Tycho Brahe, &c. Opinions concerning a plurality of worlds.
The fifth book contains the history of astronomy, in twelve chapters. In the firft, the Author gives an account of the sources from which he has drawn his information ; and charac. terizes the writers whom he has consulted. The second and third chapters exhibit the conjectures which have been formed, and the dispuics which have arisen concerning the knowledge of the Ancediluvians in astronomy, and the fabulous ages im-, mediately succeeding the food. The fourth chapter contains an account of the Chaldean and Egyptian astronomy, in which the Author, or his continuaior (for only part of a page of this chapter stands as it was originally written by Dr. Lorg), afsigns a much greater extent to the knowledge of thele two ancient nations in altronomy, then some late authors have been willing to allow. We will not enter into the dispute--the writer before us gives his reasons for what he advances, and we muft leave our readers, as he has done his, to judge for themselves on which fide truth probably lies, for after all it is but a probability. The fifth chapter treats of the astronony of the Chinese, and other Orien. cals. The writer admits the claim of the Chinese to a very early knowledge in the science, and aligns several causes for the present very low state of it in that einpire. The history of astronomy among the Greeks, before the foundation of the Alexandrian school, forins the subject of the fixib chap:er; and the writer follows the chronology of Sir Isaac Newton, in preference to the opinion of the late Mr. Cottard, who has laboured to shew that Sir Ifaac has erred near three hundred years in some of his dates. The hiftory of astronomy among the Greeks, from the foundation of the Alexandrian school to the cime of Prolemy, is difcuffed in the seventh chapter; and, in the eighth, the astronomy of the Ara. bians, Perfians, and Tartars.
We cannot help observing that an interval of near 700 years elapses between the daies contained in those two chapters, during all which time it does not appear, from this history, that a fingle
person existed who cultivated aitronomy. We cannot suppose - that the science died wholly with a person so eminent in it as Ptolemy: but it seems evidently to have been declining be.
fore his time; and, indeed, we do not find that Ptolemy himself did much more than collect together, and digest, what had been written by former astrono ners; and if any came alter him, they lived unnoticed, and in obfcurity, and their names are now buried in oblivion. It does not seem difficult to allign the cause of this total extinction of the sciences in the western world. The Romans had, for several centuries, 'been extending their conquests; and about this time made themselves masters of almost all the known world, except Perfia, and the kingdoms which lie to the eastward and northward of it; and the Romans were scarcely less ignorant of science, or less fatal to it, where. ever they came, than the Barbarians who overturned their empire were to literature in general. Nor was the Chriftian religion, or rather the bigotry of its professors, after it got established in the world, lel's inimical to the interests of science, which began not to lift its drooping head, in any country that profefled it, before the beginning of the thirteenth century; nor, without great difficuliy, for several centuries afterward: witness the cruel persecutions which were carried on against Roger Bacon, and many others, but particularly against Galileo, the morning fiar of the 17th century, as this writer, properly enough, calls bim. :. The nirth, tenth, eleventh, and twelfth books contain the history of astronomy froin the time when science began first to dawn on the horizon of Europe, after that long night of intense darkness which followed the destruction of it from the causes mentioned above, to the year 1764, when the Rev. Dr. Maskelyne was appointed stronomer Royal at Greenwich : and the writer appears to us to have dealt out his praise with a tolerably partial hand. What foreign aftronomers may think of it wen cannot say; but it undoubtedly appears from this history that much the greater part of the discoveries and improvements which have been made in the last and present centuries, as well in phyfical as practical astronomy, have been made in England. With respect to instruments, the improvements have bein wholly English fince the invention of the telescope, except the tranfit. inftrument, which was first invented and used by Rvëmer, the celebrated Danish astronomer*. And it is greatly to the ho. : * Manfredi, in his Ephemerides, gives the invention of this in. ftrument to a person of the name of Stancari. The Abbé de la Caille also tells us, in his Ephemerides for the 10 years between 1765 and 1775, that both Hook and Louville had used it: but when, or who Stancari was, is not said. We know that La Caille is mistaken with respect to Hook: on the contrary, we are certain that Ro mer both contrived and used one about the year 1700. See Horreborg Basis Aftronomia, p. 143, &c.