line
of gaseous nebulae.[1471] The star had, in fact, so far as outward
appearance was concerned, become transformed into a planetary nebula,
many of which are so minute as to be distinguishable from small stars
only by the quality of their radiations. It is now, having sunk to about
the fourteenth magnitude,[1472] entirely beyond the reach of
spectroscopic scrutiny.

Perhaps none of the marvellous changes witnessed in the heavens has
given a more significant hint as to their construction than the stellar
blaze kindled in the heart of the great Andromeda nebula some
undetermined number of years or centuries before its rays reached the
earth in the month of August, 1885. The first published discovery was by
Dr. Hartwig at Dorpat on August 31; but it was found to have been
already seen, on the 19th, by Mr. Isaac W. Ward of Belfast, and on the
17th by M. Ludovic Gully of Rouen. The _negative_ observations, on the
16th, of Tempel[1473] and Max Wolf, limited very narrowly the epoch of
the apparition. Nevertheless, it did not, like most temporaries, attain
its maximum brightness all at once. When first detected, it was of the
ninth, by September 1 it had risen to the seventh magnitude, from which
it so rapidly fell off that in March it touched the limit of visibility
(sixteenth magnitude) with the Washington 26-inch. Its light bleached
very perceptibly as it faded.[1474] During the earlier stages of its
decline, the contrast was striking between the sharply defined, ruddy
disc of the star, and the hazy, greenish-white background upon which it
was projected,[1475] and with which it was inevitably suggested to be in
some sort of physical connection.

Let us consider what evidence was really available on this point. To
begin with, the position of the star was not exactly central. It lay
sixteen seconds of arc to the south-west of the true nebular nucleus.
Its appearance did not then signify a sudden advance of the nebula
towards condensation, nor was it attended by any visible change in it
save the transient effect of partial effacement through superior
brightness.

Equally indecisive information was derived from the spectroscope. To
Vogel, Hasselberg, and Young, the light of the "Nova" seemed perfectly
continuous; but Huggins caught traces of bright lines on September 2,
confirmed on the 9th;[1476] and Copeland succeeded, on September 30, in
measuring three bright bands with an acute-angled prism specially
constructed for