ASTRONOMY DURING THE CENTURY
By SELDEN J. COFFIN, A.M.,
Professor of Astronomy, Lafayette College, Easton, Pa. ITS PROGRESS, ACHIEVEMENTS, AND NOTABLE RESULTS
Astronomy, the oldest of all the family of sciences, is not a whit behind its sister branches in activity of research and brilliance of discovery. The assiduity and zeal of its devotees are marvelous. The celestial field is so wide, the depths of space between the stars so vast, that no assurance can ever be given to an astronomer that a lifetime of faithful and intelligent research will be rewarded with even a single discovery of importance. In this respect it differs materially from other branches of science.
Nevertheless the patient labor of those who serve in its temple has rarely failed to receive an adequate reward. The discovery made in August, 1877, by Professor Asaph Hall, of Washington, that the planet Mars is attended by two satellites, is a convincing illustration of this peculiarity of the pursuit of astronomy as a study. An indefatigable watcher of the skies for many years, Professor Hall, looking at this planet at its opposition in 1877, when it was unusually near to the earth, was surprised to note two tiny points of light quite close to it; seeing them again the next evening, changed in their positions relative to Mars, it flashed upon him that the firm tradition that Mars had no moons was now disproved. His name will be forever associated with these two bodies, Deimos and Phobos, as their discoverer, although they are but wee orbs, only seven miles in diameter.
I. ASTRONOMY A CENTURY AGO.
The end of the eighteenth century found the Copernican theory of astronomy well established, the principles laid down by Kepler and Newton fully elaborated, and the application of the higher mathematics to the needs of astronomy complete. But there were, as yet, no large telescopes, and observatories were few. In Germany, a great disposition to make observations in this science and in meteorology was displayed in 1783 and for a few years following, and the records then made have proved of much value in confirming discoveries announced at later periods.
When Sir William Herschel, on March 13, 1781, pointed out a little star in the constellation of the Twins, and found that it had a perceptible disk and a slight motion, and was therefore not a star, but a newly found planet, to which the name Uranus was soon given, a careful inspection of the notebooks of previous observers showed that Uranus had been observed and recorded as a fixed star on twenty previous occasions in that century. One man had seen it twelve times, and made his record of it on a paper bag purchased at a perfumer’s. Had he been a man of sufficient order and method to have penned what he saw on the regular records of his observatory, to him would have come the glory of the great discovery of that century.