i88i.] 
Astronomical Notes . 
655 
between Saturn and Uranus. The six comets of the “ Nep- 
tune group ” have their aphelia beyond that planet inside 
35 “ Earth’s radii,” inside the first half of the distance from 
Neptune towards A, at distance 42. 
Comets 1857 IV. to 1855 II. all have their aphelia near 
and somewhat beyond 76 “ Earth’s radii,” the distance I got 
for B, to which I assigned a considerable eccentricity. 
The position of B comes next to that distance which you 
give to your inner planet. Most of the aphelia of this group 
exceed 6 for B in like proportion, as the aphelia of the 
first group exceed a = 30 for Neptune. 
The group from 285 to 420 “ Earth’s radii ” is the reason 
thatyou place a second planet at 300 such radii : 242 “ Earth’s 
radii ” equal 524,282, or solar radii fall some distance inside 
300 such radii, and play, in my development theory of the 
solar system, a prominent part. 
The last comet on the list, at ^ = 4275, falls little inside 
I C, the radius of 9,248,007 of the motion volume of the solar 
system. 
To show that your method may also work in favour of the 
distances and positions I obtained for A and B, I take the 
Neptunian group, because that planet is known, and because 
A at 42 corresponds to your planet placed by hypothesis at 
100, whose position you consider best established. 
The group lays entirely within the first half of the pro- 
portionally next great distance between Neptune and A, 
which I took to be at present at 201° with error in less. 
You mention a star observed in i860 : supposing it was A, 
it would be now about 196°. I take this instead of 20Y. 
Of Comet I., 1852, iv., you say “ It does not seem to fit 
in ” with Neptune. Its aphelion falls in 215 0 . At the time 
of the passage in 1607, A was at 202°. 
Comet III., 1815, has its aphelion in 32V; it passed it in 
1500, 1570, 1640, and 1710. In 1500 Neptune was in 296°, 
and in 1710 A was in 335°. 
Comet II., 1812, is said to have passed its aphelion in 
1635 in 256° ; Neptune was then in 242 0 , and A in 245 0 . 
Comet IV., 1846, iv., and V., 1847, v., of which the aphelia 
in 260° about coincided in 1810 with the longitude of Nep- 
tune, had the nearest coincidence with A in 1666 and 1660 
respectively, at 20° and 12° difference. 
It is characteristic for cometary changes that I. 1852, iv., 
of which you say “it does not fit in” with Neptune, but 
fits so well with A, has its aphelion nearest to Neptune 
within the group ; and that the two last comets, which in 
their last revolution do not fit with A, but so well with 
