SEEKING FOR COMETS.

Colonist, Volume II, Issue 121, 17 December 1858, Page 4

SEEKING FOR COMETS.

The great observatory at Harvard College was established in 18*47. Among the many brilliant discoveries made there since its establishment, are no less than fourteen comets. Nine were discovered by the indefatigable labours of Mr. George P. Bond. The tenth was discovered in March 1853, by Mr. Charles W. Tuttle. The remaining four by Mr. Horace P. Tuttle. Few persons are aware of the patience and labour exercised by the astronomer in making discoveries of this kind. It requires several years' study and practice to qualify one to discover a telescopic comet. It is undoubtedly very easy to look at a comet already visible to the naked eye in the heavens; but when it is required to discover an unknown one, wandering in its •• long travel of a thousand years" in the profound abyss of space, the labour then becomes truly prodigious. The amount of physical suffering occasioned by exposure to all kinds of temperature, the bending and twisting of the body when examining near the zenith, and the constant strain of the eye, cannot be fully understood and appreciated by one unacquainted with an astronomer's life.

The astronomer, with his telescope, begins at the going down of the sun, and examines, in zones with the utmost care and vigilance, the starry vault, and continues "till the "circling hours" bring the sun to the eastern horizon, when star and comet fade from his view. It requires several nights to complete a thorough 6urvey of the heavens; and often these nights do not follow in succession, being interrupted by the full moon, by clouds, auroras, and by various other meteorological phenomena. He is frequently vexed by passing clouds, fleeting through the midnight sky, and strong and chilly breezes of the night. His labours are continued throughout the year, and his unwearied exertions do not slacken during the long wintry nights, when the frozen particles of snow and ice, driven before the northern blast, cause the star to sparkle with unusual lustre, and his breath to congeal on the eye-piece of the telescope. It frequently happens that his labours are not crowned with a discovery until after several years' search.

Nothing can exceed the sublime spectacle presented to the astronomer under a clear midnight sky, as he sweeps athwart the gorgeous constellations in their "starry dance," around their appointed centre. Occasionally the field of the telescope is filled with the dazzling radiance of unnumbered suns of a variety of rich and beautiful colors. The field of the telescope is often illuminated by the sudden transit of a far off meteor, invisible to the naked eye. Sometimes a large one falls from the zenith, and, silently exploding, fills the midnight sky with a startling spectral light. The solitude and silence of the night is broken in spring, summer, and autumn, by the low murmuring voices of migrating birds, and the half-suppressed buftetting of their weary wings* which darken for a moment the field of the telescope in the flight. These are the only living companions of the- astronomer afloat in the sky at midnight.

There is a momentary excitement when hie wearied eye detects a small wisp of pale scattered light in the field of his telescope. It is very, comet-like, but he does not feel quite sure that he is not tantalised with a nebula—a cluster of suns—so remote as to defy the utmost power of assisted vision to resolve it into its individual components. He immediately ascertains the exact position, and examines the catalogues for information of its character. If it is unrecorded, he is obliged to bring the wondrous mechanism of the human hand to his assistance. The sidereal clock, and the minutely graduated circles of his telescope, inform him of his right ascension and decimation. Usually the distance of the unknown body is rigorously measured by the micrometer—a work of unsurpassed delicacy—from a star in the same field. At the end nf several hours his labors are rewarded by the discovery of a new nebula, or the slow but decisive motion of a new comet. It is a new moment of intense feeling. A new globe has hove, in sight from the utmost bound of human vision. • Whither has it come ? and whither is it going ? What is its distance from the earth and from the sun ? When will it be nearest to the earth, and when to the sun ? What is its velocity and magnitude? Will it ever become visible to the naked eye ? and has it ever before appeared within the memory of man on the records of history ? These are questions that he cannot immediately answer. His mind, aided by the most powerful analysis, penetrates into the secret workings of the Infinite mind, and by a mysterious process resolves the answers to his queries.

Three complete observations, made on three different days, or longer intervals of time, furnish him with the basis of his calculations, of the unknown particulars of the comet. They are technically called the elements of its orbit. With these three great celestial marks, he proceeds to the calculation of the element, a work of exceeding great labour and difficulty. It is a problem of pure geometry; and the illustrious Newton, who first solved this gigantic problem and applied it successfully to the great comet of 1680 pronounced, it " Probkma longe difficilimiim." A distinguished American astronomer of the last century, Rittenhouse of Philadelphia, was the first American that solved the problem. He computed the element of the comet of 1770, and says of it, in a letter to the President of the American Philosophical Society," Herewith I send you the fruit of three or'four days'labour, during which I have covered several sheets, and literally drained ray inkstand several times. Our

celebrated countryman and neighbour, Dr. Bowditch, computed the elements of the great comet of 1807, and the greater one of 16l 1, the latter yet remembered by all our

aged citizens, as it appeared in the autumal months of that year, which " Burned In the arctic sky, and from its horrid air

Shook pestilence and war." ! In 1849 the learned world in America and Europe was astonished at the production of the elliptic elements of the first comet of that year, by the wonderful Stafford, then only fourteen years of age. No mathematical genius in the history of our race has ever achieved such an honour at so early an age. The late King of Denmark, a great patron of astronomy, in the last years of his life, decreed that a gold medal should be - awarded to the first discoverer of a comet. Miss Maria Mitchell, of Nantucket, discovered a comet in October 1847, and received therefore a comet medal, and was furthered honoured by being made a member of the American Academy of Arts and Sciences. The King soon after deceased, and his successor appropriated his revenues to other purposes. The discontinuance of the Denmark medal has not in the least degree abated the zeal of the astronomers. The discovery of the same comet by different astronomers in different parts of the world, on the same night,-or within a few days of each other, attest their unremitting vigilance.— Reiobunjport Herald.