progress through space a widespread flock of small meteors forming a
dark nebula. As it plunged into the swarm the friction of the
innumerable collisions with the meteors heated its surface to
incandescence, and being of vast size it then became visible to us as
a new star. Meanwhile the motion of the body through the nebula, and
its rotation upon itself, set up a gyration in the blazing atmosphere
formed around it by the vaporized meteors; and as this atmosphere
spread wider, under the laws of gyratory motion a rotation in the
opposite direction began in the inflamed meteoric cloud outside the
central part of the vortex. Thus the spectral lines were caused to
show motion in opposite directions, a part of the incandescent mass
approaching the earth simultaneously with the retreat of another part.
So the curious spectroscopic observations before mentioned were
explained. This theory might also account for the appearance of the
nebulous spiral first seen some six months after the original
outburst. The sequent changes in the spectrum of the ``nova'' are
accounted for by this theory on the assumption, reasonable enough in
itself, that at first the invading body would be enveloped in a
vaporized atmosphere of relatively slight depth, producing by its
absorption the fine dark lines first observed; but that as time went
on and the incessant collisions continued, the blazing atmosphere
would become very deep and extensive, whereupon the appearance of the
spectral lines would change, and bright lines due to the light of the
incandescent meteors surrounding the nucleus at a great distance would
take the place of the original dark ones. The vortex of meteors once
formed would protect the flying body within from further immediate
collisions, the latter now occurring mainly among the meteors
themselves, and then the central blaze would die down, and the
original splendor of the phenomenon would fade.