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constant and immutable law, which all the bodies of the universe inviolably observe in their circulations; namely, 1 hat the squares of their periodical times are as the cubes of their distance* from the centre of the orbit, about 'which they regularly perform their motims. We are indebted to the sagacity of Kepler for the discovery of this law; he was indeed one of the first founders of modern astronomy. I cannot conclude this general survey ,~f the solar system better than in the words of that excellent mathematician, Mr. Machurin. "The view of nature, which is the immediate object of sense, is very imperfect, and of small extent; but, by the assistance of art, and the aid of reason, becomes enlarged, till it loses itself in infinity. As magnitude, of every sort, abstractedly considered, is capable of being increased to infinity, and is also divisible without end; so we find that, in nature, the limits of the greatest and least dimensions of things, are actually placed at an immense distance from each other.
"We can perceive no bounds of the vast expanse, in which natural causes operate, arid fix no limit, or termination, to the universe. The objects we commonly call great, vanish, when we contemplate the vast body of the earth. The terraqueous globe itself is lost in the solar system; the sun itself dwindles - into a star; Saturn's vast orbit, and all the orbits of the comets, crowd into a point, when viewed from numberless places between the earth and the nearest fixed stars. Other Sut^s kindle Jo illuminate other systems, where our su i s rays are unperceived; bu/t they also are swallowed lip in the vast expanse. When we have risen so high, as to leave all definite measures far behind us, we find ourselves no nearer to a term or limit.
"Our views of nature, however imperfect, serve to represent to us, in a most sensible manner, that mighty power which prevails throughout, acting with a force and efficacy that suffers no diminution from the greatest distances of space, or intervals of time; and to prove that all things are ordered by infinite wisdom and perfect goodness; scenes which should excite and animate us to correspond with the general harmony of nature."
ACCOUNT OF THE DISCOVERY OF THE FOUR NEW PLANETS NAMED CERES, PALLAS, JUNO, AND VESTA*.
Professor Piazzi, of the university of Palermo, in Italy, a very able astronomer, discovered on the first of January, 1601, a moveable star which had the appearance of a new planet; he estimated its bulk to be about It that of the earth ; and its position in our system to be between Mars and Jupiter. In compliment to the present sovereign, the founder of the Palermo observatory, he denominated it Ceres Ferdinandia; and it is now generally called Ceres. Subsequent observations on this planetary bodymade by Dr, Maskdyne, Dr. Herschel, and other astronomers of this country, France, and Germany, appear at present to confirm its identity with the other planets. On the 4th of February, 1802, Dr. Maskelyne at the Royal Observatory, Greenwich, observed this planet passing the meridian, between 3 and 4 o'clock in the morning, having about 188* 43'right ascension, and 12 38'north declination, in appearance like a star of the 8th magnitude; and preceding the 11th of the same month, he had sufficiently observed it, so as fully to ascertain its motion. With a power of Go, it appeared to have a visible disc, when on the meridian; and through a clear air, the disc was round and well defined, and rather smaller than that of the 34th of Virgo, an approximate star of the 6th magnitude; at the same time Dr. Maskelyne remarked that the smallness and rotundity of the appearance of the fixed stars is a good criterion of the clearness of the air. The light of this planet is of a reddish hue, and has been judged to resemble that of the planet Mars. From the earth's position and quicker motion in its orbit, it appeared stationary on the 6th and 7th of February last, and has had since an apparent retrograde motion. Dr. Herschel judges it to be not larger than a fourth part of the diameter of the Georgium Sidus, and its apparent diameter 22". This planet was in opposition to the sun on March 17, 1802. Therefore, at this time, October 6th, its proximity to the sun, and twilight, prevents any observation. In the month of January next, observations of it may be re-as»umed. Baron De Zuctis commutation of its place for April 6th last, was 178° 29' right ascension, and 18' 10' north declination.
* 1 have availed in) si If of the opportunity, ia the present edition, of inserting the above discoveries.—Edit.
On the 28th of March, 1802, a remarkable discovery of another new planetary body was made by Dr. Olbers, of Bremen, in Germany; it is of small apparent magnitude, and then formed an equilateral triangle with the stars 20 and 19 of Virgo; he found it had a perceptible change of place, and the following observations were communicated by him of it, to an astronomer, Dr. Schroetfr.
1802. March 28'' 9" 25' 10' meantime
App. R.Ascen. 184° 56'49" App. Declin. 11. 33 3O N 29" S* 49' 14" M. T. App. R. A. 184 46 36
App. Declin. 11 52 59 N
Dr. Olbers did not observe any sensible disc; in comparison to Ceres, its light was pale and white, and less bright than the Georgium Sid us; he has given it the name of Pallas. From calculations made by Dr. Gauss, founded upon a set of observations by Baron de Zuch, it appears that it is a planetary body moving between the orbits of Mars and Jupiter, with a very great eccentricity and inclination, and whose orbit comes very near to the orbit of the planet Ceres. Dr. Herschel, from his observations upon this planetary body, judges the apparent diameter to be rather less than Ceres, about 13" or 17', and its diameter in English miles 93 or 71, and that of Ceres l63, to have a colour less ruddy than Pallas; both this and Ceres, to have generally coma* or haziness about them, he thinks
OF CERES, PALLAS, JUNO, AND VESTA. 57
that they both differ from the general character of planets in their diminutive dimensions, in their great inclination of their orbits, in the comas surrounding them, and in their mutual proximity of their orbits; that they differ from comets in their defect of eccentricity, and of a considerable nebularity.
Pallas, like Ceres, will not be sufficiently apparent till January next (1803). Baron dc Zuch has given us the positions for the 29th of June last (18O2) us follows, 188" 32'right ascension, and iyo6'N. declination, and observes that it may be difficult to find Pallas next year; for the elements of an orbit calculated upon so small an arc as 7?", may give an error of several degrees in January, 18O3.
Dr. fferschel, from his observations of these two bodies, considers them as holding amiddle rank between planets and comets, and has denominated them Asteroids. Philosophical Transactions, 1802. On this account, I shall forbear the insertion of the several published tables of the motions'of these two planets, as calculated upon the elements computed, by various ingenious astronomers.
Mr. Harding, of Libenthal, in Bremen, discovered, on the 1st of September, 1804, another kind of planet, which has been named Juno, with an appearance like a star of the eighth magnitude. This and the preceding two have been judged to be nearly equidistant from the sun.
Dr. Olbers, on the evening of the 2.9th of March, ISO;, discovered another planet, which has been named f'esta. Its right ascension then was 184° 8',