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estion whether the newly detected star was fixed or moving body. On the evening of the 2d of January he repaired to his observatory, and so soon as the fading twilight permitted, directed the telescope to the exact point in which, on the preceding evening, his suspicious star had been located. The spot was blank! But another, which was distant 4' in right ascension, and 3' in declination, which, on the previous night had certainly been vacant, was now gleaming with the bright little object which, on the preceding evening, had so earnestly fixed his attention, and for which he was again so anxiously seek ing. Night after night he watched its retrograde motion, a motion precisely such as it ought to have, in case it were the long desired planet,-until, on the 12th, it became stationary, and then slowly commenced progressing in the order of the signs. Piazzi was unfortunately taken ill; his observations were suspended, and such was the difficulty of intercommunication, that, although he sent intelligence of his discovery to Bode and Orani, associates in the great enterprise, the newly discovered body was already lost in the rays of the sun, before it became possible to renew the train of observations by which its orbit might be made known. Piazzi feared to announce the newly discovered body to be the suspected planet. His observations were few, and he was the only person in the world who had seen it. Bode no sooner received the intelligence of its discovery, than he at once pronounced it to be the long sought planet, and from the scanty materials furnished by Piazzi, Olbers, Burkhart, and Gauss, all computed the elements of its orbit, settled the great fact that it was a superior

planet, and that its orbit was included between those of Mars and Jupiter. Some doubt, however, yet rested on the subject, and the disengagement of the planet from the beams of the sun was awaited with the deepest interest.

Several months passed away. Every eye and every telescope was directed to the region in the heavens where the new planet was expected to be found. The most scrutinizing search was made for its rediscovery, but without any success. But for the high reputation of Piazzi, his well known accuracy and honesty, doubts would have arisen as to whether he had not been self-deceived, or was intentionally deceiving others. The subject became of deeper and deeper interest. The world began to sneer at a science which could find a body in the heavens, and then forever lose it. We must remember that Piazzi had followed it through only about 4° out of 360° of its orbit, and on this narrow basis a research was to be instituted, having for its object the determination of the exact position which the lost planet must occupy. Gauss, then comparatively a young man, and little known as a computer, had conceived a new method of determining the orbits of comets, from a very few and very closely consecutive observations. Here was an admirable opportunity of giving a practical proof of the power of his new method. The long and intricate calculation was finished, the place of the lost planet determined, the telescope was directed to the spot, and lo! the beautiful little orb flashed once more on the eager gaze of the youthful as ronomer. For one entire year had the planet been sought in vain, and but for the powerful analysis of Causs, nothing

but years of persevering toil could have wiped away the reproach which rested on astronomy.

A sufficient number of observations were soon made to reveal the orbitual elements of the planet, now named Ceres. It was found, in all respects, to narmonize in its movements with the older planets, and its orbit filled precisely the blank in the strange empirical law discovered by Bode. The period and distance hypothetically computed from that law sixteen years before, by Baron de Zach, were verified in the most remarkable manner by the actual period and distance of Ceres. Order and beauty now reigned in the planetary system, and a most signal victory had crowned the efforts of astronomical science.

The only remarkable difference between the new planet and the old ones, consisted in its minute size, the great obliquity of its orbit, and the dense atmosphere by which it appears to be surrounded. Its diameter is so small as to render its measure next to impossible, and the best practical astronomers differ widely in their results. Sir William Herschel makes its diameter only 163 miles, while Schroeter cannot make it less than ten times that quantity. The mean of these two extremes is probably near the truth.No satellites have been found in attendance on this minute planet, although Sir William Herschel suspected the existence of two at one time, a suspicion which subsequent observations have not confirmed.

The beautiful order established in the solar system by the discovery of Ceres was a subject of the highest gratification to the whole astronomical world, and especially to those who had been instrumental in reaching this remarkable result. An opportunity had

scarcely presented itself for the expression of celight occasioned by this announcement, before all interested were startled by a declaration from Dr. Olbers, of Bremen, that he had found another planet on the evening of the 28th of March, 1802, with a mean distance and periodic time almost identical with those of Ceres. This discovery broke through all the analo gies of the solar system, and presented the wonderful anomaly of two planets revolving in such close proximity, that their orbits, projected on the plane of the ecliptic, actually intersected each other.

The new planet was called Pallas, and is of a magnitude about equal to that of Ceres. Its orbit is greatly inclined to the plane of the ecliptic, and its eccentricity is very considerable. The existence of these small planets, in such near proximity, for a long while perplexed astronomers. At length Olbers suggested that these minute bodies might be the fragments of a great world, rent asunder by some internal convulsion of sufficient power to produce the terrific result, but of a nature entirely beyond the boundary of conjecture.

Extraordinary as this hypothesis may appear, the results to which it led are not less remarkable. If a world of large size had been actually burst into fragments, it is easy to perceive that these fragments, all darting away in the orbits due to their impulsive forces would start from the same point, and hence would return at different intervals indeed, but would all again pass through the point of space occupied by the parent orb when the convulsion occurred. Hav. ing found two of these fragmentary worlds, the point of intersection of their orbits would indicate the re

on through which the other fragments might be expected to pass, and in which they might possibly be discovered. So reasonable did the views of Olbers appear, that his suggestions were immediately acted upon by himself and several distinguished observers, and on the 2d of September, 1804, Mr. Harding, of Lilienthal, while scrutinizing the very region indicated by Olbers, detected a star of the eighth magnitude, which seemed to be a stranger, and was soon recognized to be another small planet, fully agreeing, in all its essential characteristics, with the theory of Olbers. The new world was named Juno, and is remarkable for the eccentricity of its orbit. Its diameter has not been well determined, owing to its minute size. This discovery gave to the theory of Olbers the air of reality, and finding the nodes of the three fragments to lie in the opposite constellations Cetus and Virgo, he prosecuted his researches in these regions with redoubled energy and zeal.

His efforts were not long without their reward. On the 29th of March, 1807, he detected the fourth of his fragments in the constellation Virgo, and very near the point through which he had, for four years, been waiting to see it pass. This was a most wonderful discovery, and almost fixed the stamp of truth upon the most extraordinary theory which had ever been promulgated. This new asteroid was named Vesta and for nearly forty years, the examinations which were conducted revealed no new fragment, and it began to be regarded as positively ascertained, that all the small bodies revolving in this region had been revealed to the eye.

But on the 8th day of Dec., 1845, Mr. Hencke, of