Comets and Meteors / Their phenomena in all ages; their mutual relations; and the theory of their origin.

by Daniel Kirkwood

Perihelion Passage.			Per. Dist.	Long. of Per.
1. 1668, Feb.	28d.	13h.	0.0047	277°	2´
2. 1680, Dec.	17	23	0.0062	262	49
3. 1843, Feb.	27	9	0.0055	278	39

In Table II. all but the last have their perihelia in the same quadrant.

II. Comets whose Perihelion Distances are Greater than 0.01 and Less than 0.05.

Perihelion Passage.			Per. Dist.	Long. of Per.
1. 1689, Nov	29d.	4h.	0.0189	269°	41´
2. 1816, March	1	8	0.0485	267	35
3. 1826, Nov	18	9	0.0268	315	31
4. 1847, March	30	6	0.0425	276	2
5. 1865, Jan	14	7	0.0260	141	15

The perihelion of the first comet in Table III. is remote from the direction of the sun's motion; that of the second is distant but 14°, and of the third 21°.

III. Comets whose Perihelion Distances are Greater than 0.05 and Less than 0.1.

Perihelion Passage.			Per. Dist.	Long. of Per.
1. 1593, July	18d.	13h.	0.0891	176°	19´
2. 1780, Sept.	30	22	0.0963	246	35
3. 1821, March	21	12	0.0918	239	29

With greater perihelion distances the tendency of the perihelia to crowd together round the point indicated is less distinctly marked.

6. Few comets of small perihelion distance should have their perihelia in the vicinity of longitude 80°, the point opposite that towards which the sun is moving. Accordingly we find, by examining a table of cometary elements, that with a perihelion distance less than 0.1 there is not a single perihelion between 35° and 125°; between 0.1 and 0.2 but 3; and between 0.2 and 0.3 only 1.

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