II. SYNOPTIC TABLE OF THE ELEMENTS OF THE

PLANETARY SYSTEM.

N.B. -a denotes the mean distance from the sun, that of the earth being taken for unity; P the mean sidereal period in mean solar days; e the eccentricity in decimal parts of the semi-axis; i the inclination of the orbit to the ecliptic; & the longitude of the ascending node; that of the perihelion; L the mean longitude of the planet at the moment of the epoch E, for which the elements are stated; M the denominator of the fraction expressing the mass of the planet, that of the sun being 1; D the diameter in miles; ▲ the density, that of the earth being 1; T the time of rotation on its axis, in sidereal hours; d the mean angular equatorial diameter of the body of the planet, at its mean distance from the earth, in seconds; e the ellipticity of the spheroid, as a fraction of the equatorial diameter; y the inclination of the axis of rotation to the plane of the ecliptic; H the mean intensity of light and heat received from the sun, that received by the earth being 1. The asteroids are numbered in their order of discovery.

166 0 48.6 11 33 3.0 100 39 10-2 64 22 55.5 249 31 26.2 224 28 25.5 104 2 31.1 218 26 1.1 159 43 26.6 242 1 33.1 200 41 2.0 68 48 31.9 72 54 6.5 25 49 27.8 283 57 32.2 312 33 52.4 259 47 22.8 89 30 12.9 131 45 1.9 51 35 24.8 342 20 9.0 167 39 20.9 149 16 50.5

Note. The elements of the orbits of Mercury, Venus, the Earth, Mars, Jupiter, Saturn, and Uranus, are those given by the late F. Baily, Esq., in his "Astronomical Tables and Formulæ," and are the same with those which form the basis of Delambre's tables, embodying the formulæ of Laplace. The elements of Uranus and Neptune can only be regarded as provisional; those of the former requiring considerable corrections, necessitated by the discovery of Neptune, but which, not being yet finally ascertained, by reason of the uncertainty still attending on the mass and elements of the latter planet, it was thought better to leave the old elements untouched than to give an imperfect rectification of them. Those of Neptune are Prof. Sears Walker's, as stated in Berl. Ephem. 1858, p. 408. The masses of the planets are those most recently adopted by Encke (Ast. Nachr. No. 443.), on mature consideration of all the authorities, that of Neptune excepted, which is Prof. Pierce's determination from Bond's and Lassell's observation of the satellite discovered by the latter. The densities are calculated from the values adopted for M, D, and E.

The elements of the Asteroids, Nos. 1-42, with exception of Flora and Daphne, are those used in the Supplement to the Nautical Almanac for 1861. Those of the two last named Asteroids are Brünnow's and Pape's, given in the Berl. Ephem, for 1860. The elements of Nos. 43, 44, 45, 46, are those of Pape and Förster, as stated in Ast. Soc. Notices, vol. xvii.; of Nos. 47, 48, 49, 50, those given respectively by Bruhns, Powalsky, and Encke, in Astron. Nachr., Nos. 1117, 1115, 1115, 1127. The elements of Nemansa (if it be really to retain so uncouth a name), and of No. 52, have not yet come to our knowledge. Those of Eugenia (45.) are very uncertain.

The elements of the recently-discovered small planets may undergo material corrections from further observation. The orbits of Astræa and Hygeia approach at one point (their common node) within 0·006 of the radius of the earth's orbit. Many of the names of the Asteroids appear to us very unhappily chosen. Thus, confusion is very likely to arise in printing or speaking, between Iris and Isis, Lutetia and Lætitia, Thetis and Metis, Thetis and Themis, Vesta and Hestia, Hygeia and Egeria, Egeria and Eugenia, Pallas and Pales. Is it too much to hope that the discoverers of the interfering members of these pairs will reconsider their names? It is not yet too late: there is yet a Muse or two left; the Nymphs, Dryads, Oceanidæ, &c., afford an infinite choice of classic names, graceful and euphonous. Metis is known to few as a mythological name, Pales to fewer as that of a female divinity, Nemansa to none as the name of anybody (the ancient name of Nismes was Nemansus).

III.

SYNOPTIC TABLE OF THE ELEMENTS OF THE ORBITS OF THE SATELLITES, SO FAR AS THEY ARE KNOWN.*

* The distances are expressed in equatorial radii of the primaries. epoch is Jan. 1. 1801, unless otherwise expressed. The periods, &c., are expressed in mean solar days.

The