The errors of the Ptolemaic theory of the universe have now been long discarded; but there are many points in which modern sciences, and modern astronomy in particular, have reaped incalculable benefits from the labours and researches of its great founder. He has preserved and transmitted to us the observations and principal discoveries of remoter periods, and has enriched and augmented them with his own. He corrected Hipparchus’s catalogue of the fixed stars, and formed tables for the calculation and regulation of the motions of the Sun, Moon, and planets. He was, in fact, the first who collected the scattered and detached observations of Aristotle, Hipparchus, Posidonius, and others on the economy of the world, and digested them into a system, which he set forth in his Μεγαλη Σνταξις or Great Construction, divided into thirteen books, and called, after him, the Ptolemaic System. This and all his other astronomical works are founded upon the hypothesis, that the earth is at rest in the centre of the universe, and that the heavenly bodies, stars, and planets, all move round it in solid orbs, whose motions are all directed by one _primum mobile_, or first mover, of which he discourses at large in the “Great Construction.” In that work he also treats of the figure and divisions of the earth, of the right and oblique ascensions of the heavenly bodies, and of the motions of the Sun, Moon, and planets; and he gives tables for finding their situations, latitudes, longitudes, and motions: he treats also of eclipses, and the methods of computing them; and he discourses of the fixed stars, of which he furnishes a numerous catalogue, with their magnitudes, latitudes, and longitudes.[9] It has been truly said, that “Ptolemy’s order, false as it was, enabled observers to give a plausible account of the motions of the Sun and Moon, to foretell eclipses, and to improve geography[10];” or, in other words, that it represented the actual phenomena of the heavens as they really appear to a spectator on the earth. It is therefore clear that Ptolemy’s astrology is just as applicable to modern and improved astronomy as it was to his own.[11] [9] In France, about the beginning of the 16th century, Oronce Finé, the Royal Reader, attempted, under the patronage of Francis I, to produce an astronomical clock, in which everything moved according to the principles of Ptolemy. It was kept, about fifty years ago, in the monastery of St. Geneviéve, at Paris. In Lilly’s Catalogue of Astrological Authors, Orontius Finæus is mentioned as the writer of a work on the twelve houses of heaven, printed in Paris, 1553. [10] _Spectacle de la Nature._