scope may perfectly separate them so far as the stellar disks are concerned. Then, too, I have observed in my own experience that a very faint and close double is more difficult than a brighter pair not more widely separated, usually on account of the defect of light, and this is true even when the components of the faint double are of equal magnitude.
Σ 470, otherwise known as 32 Eridani, is a superb object on account of the colors of its components, the larger star being a rich topaz and the smaller an ultramarine; while the difference in magnitude is not as great as in many of the colored doubles. The magnitudes are fifth and seventh, distance 6·7″, p. 348°. The star γ, of magnitude two and a half, has a tenth-magnitude companion, distant 51″, p. 238°. Σ 516, also called 39 Eridani, consists of two stars of magnitudes sixth and ninth, distance 6·4″, p. 150″; colors, yellow and blue. The supposed binary character of this star has not yet been established.
In ο2 a we come upon an interesting triple star, two of whose components at any rate we can easily see. The largest component is of the fourth magnitude. At a distance of 82″, p. 105°, we find a tenth-magnitude companion. This companion is itself double, the magnitudes of its components being tenth and eleventh, distance 2·6″, p. 98°. Hall says of these stars that they "form a remarkable system." He has also observed a fourth star of the twelfth magnitude, distant 45″ from the largest star, p. 85°. This is apparently unconnected with the others, although it is only half as distant as the tenth-magnitude component is from the primary. Σ 590 is interesting because of the similarity of its two components in size, both being of about the seventh magnitude, distance 10″, p. 318°.
Finally, we turn to the nebula 826. This is planetary in form and inconspicuous, but Lassell has described it as presenting a most extraordinary appearance with his great reflector—a circular nebula lying upon another fainter and larger nebula of a similar shape, and having a star in its center. Yet it may possibly be an immensely distant star cluster instead of a nebula, since its spectrum does not appear to be gaseous.