Popre.—On the Southern Stars and other Celestial Objects. 169 
its sensitiveness to the feeble red, orange, and yellow rays of the small 
star return, and it sees the small star to be white or nearly so. On the 
other hand, I have often noticed that the longer one looks at a double star 
of this kind, both stars being in the field, the more pronounced does the 
blue become. There is only one instance, that I am aware of, in which 
this theory will not hold good. The small companion of a Scorpii is un- 
doubtedly really greenish. I saw it on the 28rd of March, 1878, emerge 
from behind the moon after an occultation while its bright companion was 
still hidden, its colour then was a pale pea-green. There could have been 
no contrast here, except with the moon’s light; admitting this exception, 
however, it seems to me highly probable that while, in such wide double 
stars as m Argus and y Crucis the orange or yellow star is really what it 
seems, the star that appears green or blue is, as a rule, really white. If 
this view is the correct one, it follows that those observers who spend a 
great deal of time in observing the tints of the companions to large stars, 
are, to a great extent, wasting their time. 
y Argus.—This fine second-magnitude multiple- star has a very curious 
tol le It belongs to a very small class of stars, the only other one 
that I have heard of is in the Northern constellation Cassiopeia. In the 
spectrum of y Argus there are certainly three very bright lines, one rather 
faint, and, I believe, many finer ones. I am almost certain, too, that there 
are several fine dark lines in the spectrum. The brightest line is, not 
improbably, the F. hydrogen line; and the somewhat fainter one, the C. 
hydrogen line. Of the other two very distinct bright lines, one is certainly 
not very far from the position of the D. sodium line; but I cannot place 
the other. The presence of bright lines in the spectrum renders it far 
more difficult than usual to estimate the positions, but the other line seems 
to be about one-third of the distance from D. towards the iron line E. Not 
improbably then, outside the photosphere of y Argus, there are ever-present 
enormous masses of hydrogen and sodium, as well as other substances in the 
gaseous condition, which have been ejected from the more central parts o 
this sun; and, the temperature of these incandescent gases being much 
higher than that of the solar photosphere below, their spectrum is super- 
imposed on the ordinary spectrum of the star proper. 
£ Argus.— his yellow star belongs to Secchi’s second class. In these 
stars the lines are very fine, and not easily seen unless the weather is very 
favourable. To this class our sun belongs. In the spectrum of e Argus 
the F. line can be seen pretty easily, but the D. sodium line seems to be 
the most distinct of this spectrum. 
B Argus.—Magnitude, one and a-half. Colour, white. A first-class 
star. The hydrogen lines are pretty broad and distinct. “ 
