" | 9 |1 & 8 | Rigel. |
| 9.| d " | " | 10 |2 & 8 | Red and white. |
|10.| th " | " | | |Septuple. |
|11.| l " | " | 5 | |White and violet. |
|12.| s " | " A, B.| 11 |4 & 10|Octuple. |
|13.| Castor | 69 | 5-1/2|2 & 3 |White. |
|14.| Pollux | 69 | |Triple|Orange, gray, lilac. |
|15.| g Virginis | 70 | 5 |3 & 3 |Both yellow. |
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]

When g Virginis was observed in 1718 by Bradley, the component
parts were 7" asunder. He incidentally remarked in his note-book
that the line of their connection was parallel to the line of the
two stars Spica, or a and d Virginis. By 1840 they were not more
than 1" apart, and the line of their connection greatly changed.
The appearance of the star is given in Fig. 75 (15), commencing
at the left, for the years 1837 '38 '39 '40 '45 '50 '60 and '79.
also a conjectural [Page 213] orbit, placed obliquely, and the
position of the stars at the times mentioned, commencing at the top.
The time of its complete revolution is one hundred and fifty years.

[Illustration: Fig. 75.--Aspects and Revolution of Double Stars.]

The meaning of these double stars is that two or more suns revolve
about their centre of gravity, as the moon and earth about their
centre. If they have planets, as doubtless they have, the movement
is no more complicated than the planets we call satellites of Saturn
revolving about their central body, and also about the sun. Kindle
Saturn and Jupiter to a blaze, or let out their possible light, and
our system would appear a triple star in the distance. Doubtless,
in the far past, before these giant planets were cooled, it so
appeared.

We find some stars double, others triple, quadruple, octuple, and
multiple. It is an extension of the same principles that govern
our system. Some of these suns are so far asunder that they can
swing their Neptunes between them, with less perturbation than
Uranus and Neptune have in ours. Light all our planets, and there
would be a multiple star with more or less suns seen,
[Page 214]
according to the power of the instrument. Perhaps the octuple star
s in Orion differs in no respect from our system, except in the
size and distance of its separate bodies, and less co