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. II. HOW “BODE’S LAW” PROMOTED RESEARCH. An erroneous guess, if it is a good guess, sometimes produces excellent results. In 1778, Bode, of Berlin, published a “law” that states the distances of the various planets from the sun. It is often expressed simply in this way: Set down 4, and add to it successively the numbers 3, 6, 12, 24, etc., and the sums obtained, viz., 4, 7, 10, 16, 28, etc., represent the relative distances of all the planets from the sun, viz., Mercury 4, Venus 7, Earth 10, Mars 16, [Asteroids 28], Jupiter 52, etc. In reference to all the planets then known to exist, the correspondence of the alleged law to the facts was remarkable. The one point in which the alleged system utterly failed was in requiring the existence of a planet to fill the gap between Mars and Jupiter. So boldly did Biela press his convictions of the correctness of this law upon the notice of his fellow-workers, that they resolved, in 1800, to divide the zodiac into twenty-four zones, to be apportioned among them, for the express purpose of searching for undiscovered planets. This well-organized effort was, erelong, rewarded by the surprising discovery of four new planets, the first one on the first night of the new century, January 1, 1801, and three more soon after. As no more seemed to be forthcoming, the search was relinquished in 1816. A fifth was found in 1845, and nearly five hundred since. Since 1891 photography has been wondrously serviceable in finding these bodies. A sensitive plate, on being exposed toward that part of the sky which it is desired to examine, will record all the perceptible stars as round disks; while any planets that appear in the field of view will,