SYNOPTICAL TABLES.
351
| No. | Name. | Sidereal Revolution. |
Mean Apparent Distance. |
Discoverer, | Year of Discovery. | |||
| d. | h. | m. | s. | ″ | ||||
| 1 | Ariel | 2 | 12 | 29 | 21 | 13.54 | Lassell | 1851 |
| 2 | Umbriel | 4 | 3 | 28 | 8 | 19.28 | Lassell | 1851 |
| 3 | Titania | 8 | 16 | 56 | 31 | 31.44 | Herschel | 1787 |
| 4 | Oberon | 13 | 11 | 7 | 13 | 42.87 | Herschel | 1787 |
| Additional satellites seen by Herschel, but not re-observed, | 4 |
| Direction of movement of satellites | retrograde |
| Inclination of the orbits of Titania and Oberon to ecliptic, | 78° 58′ |
| Distance from the planet -when satellites become invisible (Herschel), | 14″ |
| IMagnifying power required for sustained view, | 300 |
| Volume (Earth's = 1), | 76.6 |
| Mass (Earth's = 1), . | 18.900 |
| Density (Earth's = 1), | .321 |
| Diameter (Earth's = 1), | 4.246 |
| Diameter in miles, | 33,610 |
| Diameterapparent, mean, | 2.″4 |
| Gravity (Earth = 1), | 1.36 |
| Gravity bodies fall in one second, in feet, | 21.8 |
| Light and heat from Sun, perihelion, | .0011 |
| Light and heat from Sun, aphelion, | .0011 |
| Year in which Adams computed its place within 2 degrees, | 1845 |
| Year in which Leverrier computed its place, | 1846 |
| First observed by M. Galle, from Leverrier's indications, 23d Sept., | 1846 |
