| The | eccentricity | of | Philomela = 0.01 |
| " | " | " | Æthra = 0.38 |
| " | " | " | Comet II. 1867 (ret. in 1885) = 0.41 |
The orbit of Æthra, it is seen, more nearly resembles the last than the first. It might perhaps be called the connecting-link between planetary and cometary orbits.
The average eccentricity of the two hundred and sixty-eight asteroids whose orbits have been calculated is 0.1569. As with the orbits of the old planets, the eccentricities vary within moderate limits, some increasing, others diminishing. The average, however, will probably remain very nearly the same. An inspection of the table shows that while but one orbit is less eccentric than the earth's, sixty-nine depart more from the circular form than the orbit of Mercury. These eccentricities seem to indicate that the forms of the asteroidal orbits were influenced by special causes. It may be worthy of remark that the eccentricity does not appear to vary with the distance from the sun, being nearly the same for the interior members of the zone as for the exterior.
7. The Inclinations.
The inclinations in Table II. are thus distributed:
| From | 0° to | 4° | 70 |
| " | 4° to | 8° | 83 |
| " | 8° to | 12° | 59 |
| " | 12° to | 16° | 32 |
| " | 16° to | 20° | 8 |
| " | 20° to | 24° | 8 |
| " | 24° to | 28° | 7 |
| " | 28° to | 32° | 0 |
| above 32° | 1 | ||
One hundred and fifty-four, considerably more than half, have inclinations between 3° and 11°, and the mean of the whole number is about 8°,—slightly greater than the inclination of Mercury, or that of the plane of the sun's equator. The smallest inclination, that of Massalia, is 0° 41´, and the largest, that of Pallas, is about 35°. Sixteen minor planets, or six per cent. of the whole number, have inclinations exceeding 20°. Does any relation obtain between high inclinations and great eccentricities? These elements in the cases named above are as follows:
| Asteroid. | Inclination. | Eccentricity. |
|---|---|---|
| Pallas | 34°42´ | 0.238 |
| Istria | 2630 | 0.353 |
| Euphrosyne | 2629 | 0.228 |
| Anna | 2524 | 0.263 |
| Gallia | 2521 | 0.185 |
| Æthra | 250 | 0.380 |
| Eukrate | 2457 | 0.236 |
| Eva | 2425 | 0.347 |
| Niobe | 2319 | 0.173 |
| Eunice | 2317 | 0.129 |
| Electra | 2255 | 0.208 |
| Idunna | 2231 | 0.164 |
| Phocea | 2135 | 0.255 |
| Artemis | 2131 | 0.175 |
| Bertha | 2059 | 0.085 |
| Henrietta | 2047 | 0.260 |
This comparison shows the most inclined orbits to be also very eccentric; Bertha and Eunice being the only exceptions in the foregoing list. On the other hand, however, we find over fifty asteroids with eccentricities exceeding 0.20 whose inclinations are not extraordinary. The dependence of the phenomena on a common cause can, therefore, hardly be admitted. At least, the forces which produced the great eccentricity failed in a majority of cases to cause high inclinations.