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SYNOPTICAL TABLES.
| Number of mountains higner than Mont Blanc, | 28 |
| Length of the range of the Lunar Appenines, in miles, | 200 |
| Proportion of surface covered with craters, | 3-5ths |
| Tycho, height in feet, | 20,180 |
| Tycho diameter in miles, | 54 |
| Tycho longest ray, | 1800 |
| Tycho number of bright rays, about | 54 |
| Diameter of Mt. Vesuvius in feet, | 500 |
| Height of Pico, a bright isolated peak, in feet, | 7060 |
| Disc of the Earth, as seen from Moon (Moon's disc = 1), | 14 |
| Proportion of the Moon's surface alternately hid and visible, | 1-7th |
| Light of the Moon at mean distance (Sun's = 1) . | 1-800000th |
| Heat of the Moon (heat of a candle at distance of 15 feet = 1), | 1-3d |
| Velocity of projection necessary for a lunar body to reach the Earth, feet, per second. | 8200 |
| Distance in miles of Moon's surface under a magnifying power of 1000, | 240 |
| A circle of one second in diameter as seen from the Earth, in square miles. | 1 |
| Limit of vision in the case of a circle or square, | 60″ |
| Limits of vision in an indefinitely extended object, | 6″ |
| Magnifying power required to see an embankment, 6 feet broad, | 6000 |
| Highest power attained with distinct vision, | 2000 |
| Maximum limit of atmosphere (one inch of mercury = 1), | 1-45th |
| Maximum limit of refraction (at surface of earth = 1), | 1-1980th |
| Maximum limit of horizontal refraction at Moon, | 1" |
| Eclipses, annual number, minimum (only solar), | 2 |
| Eclipses, annual number. maximum, | 7 |
| Eclipses, maximum of annular phase, | 12m. 24s. |
| Eclipses, totality (solar), | 7m. 58s. |
