In the year 1758, Roger Long, Lowndean Professor of Astronomy at Cambridge, constructed an “orrery” on a novel principle. It was a hollow metal sphere of about 18 feet in diameter with its fixed axis parallel to the earth’s axis. It was rotated, by means of a winch and rackwork. It held about thirty persons in its interior, where astronomical lectures were delivered. The constellations were painted on the interior surface; and holes pierced through the shell and illuminated from the outside represented the stars according to their different magnitudes. This ingenious machine was much neglected for many years, but was still in existence in Admiral Smyth’s time, 1844.[499]
A “temporary star” is said to have been seen by Hepidanus in the constellation Aries in either 1006 or 1012 A.D. The late M. Schönfeld, a great authority on variable stars, found from an Arabic and Syrian chronicle that 1012 is the correct year (396 of the Hegira), but that the word translated Aries would by a probable emendation mean Scorpio. The word in the Syrian record is not the word for Aries.[500]
Mr. Heber D. Curtis finds that the faintest stars mentioned in Ptolemy’s Catalogue are about 5·38 magnitude on the scale of the Harvard Photometric Durchmustering.[501] Heis and Houzeau saw stars of 6-7 magnitude (about 6·4 on Harvard scale). The present writer found that he could see most of Heis’ faintest stars in the west of Ireland (Co. Sligo) without optical aid (except short-sighted spectacles).
With reference to the apparent changes in the stellar heavens produced by the precession of the equinoxes, Humboldt says—
“Canopus was fully 1° 20′ below the horizon of Toledo (39° 54′ north latitude) in the time of Columbus; and now the same star is almost as much above the horizon of Cadiz. While at Berlin, and in northern latitudes, the stars of the Southern Cross, as well as α and β Centauri, are receding more and more from view, the Magellanic Clouds are slowly approaching our latitudes. Canopus was at its greatest northern approximation during last century [eighteenth], and is now moving nearer and nearer to the south, although very slowly, owing to its vicinity to the south pole of the ecliptic. The Southern Cross began to become invisible in 52° 30′ north latitude 2900 years before our era, since, according to Galle, this constellation might previously have reached an altitude of more than 10°. When it had disappeared from the horizon of the countries of the Baltic, the great pyramid of Cheops had already been erected more than five hundred years. The pastoral tribe of the Hyksos made their incursion seven hundred years earlier. The past seems to be visibly nearer to us when we connect its measurement with great and memorable events.”[502]
With reference to the great Grecian philosopher and scientist Eratosthenes of Cyrene, keeper of the Alexandrian Library under Ptolemy Euergetes, Carl Snyder says, “Above all the Alexanders, Cæsars, Tadema-Napoleons, I set the brain which first spanned the earth, over whose little patches these fought through their empty bootless lives. Why should we have no poet to celebrate so great a deed?”[503] And with reference to Aristarchus he says, “If grandeur of conceptions be a measure of the brain, or ingenuity of its powers, then we must rank Aristarchus as one of the three or four most acute intellects of the ancient world.”[504]
Lagrange, who often asserted Newton to be the greatest genius that ever existed, used to remark also—“and the most fortunate; we do not find more than once a system of the world to establish.”[505]
Grant says—
“Lagrange deserves to be ranked among the greatest mathematical geniuses of ancient or modern times. In this respect he is worthy of a place with Archimedes or Newton, although he was far from possessing the sagacity in physical enquiries which distinguished these illustrious sages. From the very outset of his career he assumed a commanding position among the mathematicians of the age, and during the course of nearly half a century previous to his death, he continued to divide with Laplace the homage due to pre-eminence in the exact sciences. His great rival survived him fourteen years, during which he reigned alone as the prince of mathematicians and theoretical astronomers.”[506]
A writer in Nature (May 25, 1871) relates the following anecdote with reference to Sir John Herschel: “Some time after the death of Laplace, the writer of this notice, while travelling on the continent in company with the celebrated French savant Biot, ventured to put to him the question, not altogether a wise one, ‘And whom of all the philosophers of Europe do you regard as the most worthy successor of Laplace?’ Probably no man was better able than Biot to form a correct conclusion, and the reply was more judicious than the question. It was this, ‘If I did not love him so much I should unhesitatingly say, Sir John Herschel.’” Dr. Gill (now Sir David Gill), in an address at the Cape of Good Hope in June, 1898, spoke of Sir John Herschel as “the prose poet of science; his popular scientific works are models of clearness, and his presidential addresses teem with passages of surpassing beauty. His life was a pure and blameless one from first to last, full of the noblest effort and the noblest aim from the time when as a young Cambridge graduate he registered a vow ‘to try to leave the world wiser than he found it’—a vow that his life amply fulfilled.”[507]