SYNOPTICAL TABLES.
355
| Halley's comet, length on 5th Nov. 1835 (perihelion 15th Nov.), | 2° 30′ |
| Halley's comet, jet and tail commenced | Oct. 2 |
| Halley's comet, oscillation of jet obvious in the course of | 1h. |
| Halley's comet, invisible after the perihelion, in months, | 2 |
| Halley's comet, diameter of disc when seen, not including coma, | 2′ |
| Halley's comet, increase of volume of illuminated space during six days, from Jan. 25, | 40 times |
| Return of Charles V. comet of 1556, predicted by Hind in period | 1856-61 |
| Period of Encke's comet, shortening at the rate, per revolution, of | Od..11 |
| Lexell's comet of 1770, period in years, | 5.5 |
| Lexell's comet of 1770, thrown out of the system by attraction of Jupiter in | 1779 |
| Lexell's comet of 1770, distance from Sun at perihelion (Sun's radius = 1), | 1-7th |
| Lexell's comet of 1770, angular diameter of Sun at perihelion, | 121° 32" |
| Lexell's comet of 1770, disc of Sun at perihelion (disc from Earth = 1), | 47,000 |
| Lexell's comet of 1770, heat at perihelion (heat of 32 inch burning lens = 1), | 25 |
| Lexell's comet of 1770, velocity at perihelion, miles, in one second, | 366 |
| Lexell's comet of 1770, tail stretching to the Earth's orbit, whirled round in two hours, | 180° |
| Lexell's comet of 1770, radius of head on 29th March, in miles, | 47,000 |
| Lexell's comet of 1770, length of tail, | 150,000,000 |
| Lexell's comet of 1770, breadth of tail, | 3,000,000 |
| Periodic comets, all direct when inclination under | 17° |
| Comets calculated before 1849, direct, | 94 |
