time masses of glowing sodium, magnesium,
and (in less degree) iron and other metallic vapours. Lastly, in that
glorious appendage, the solar corona, which extends for hundreds of
thousands of miles from the sun's surface, there are enormous quantities
of some element, whose nature is as yet unknown, showing under
spectroscopic analysis the bright line which seems to have appeared in
the spectrum of the flaming sun in the Swan.

This evidence seems to me to suggest that the intense heat which
suddenly affected this star had its origin from without. At the same
time, I cannot agree with Meyer and Klein in considering that the cause
of the heat was either the downfall of a planetary mass on the star, or
the collision of the star with a star-cloudlet, or nebula, traversing
space in one direction while the star swept onwards in another. A planet
could not very well come into final conflict with its sun at one fell
swoop. It would gradually draw nearer and nearer, not by the narrowing
of its path, but by the change of the path's shape. The path would, in
fact, become more and more eccentric; until, at length, at its point of
nearest approach, the planet would graze its primary, exciting an
intense heat where it struck, but escaping actual destruction that time.
The planet would make another circuit, and again graze its sun, at or
near the same part of the planet's path. For several circuits this would
continue, the grazes not becoming more effective each time, but rather
less. The interval between them, however, would grow continually less
and less. At last the time would come when the planet's path would be
reduced to the circular form, its globe touching its sun's all the way
round, and then the planet would very quickly be reduced to vapour, and
partly burned up, its substance being absorbed by its sun. But all the
successive grazes would be indicated to us by accessions in the star's
lustre, the period between each seeming outburst being only a few months
at first, and becoming gradually less and less (during a long course of
years, perhaps even of centuries), until the planet was finally
destroyed. Nothing of this sort has happened in the case of any
so-called new star.

As for the rush of a star through a nebulous mass, that is a theory
which would scarcely be entertained by any one acquainted with the
enormous distances separating the gaseous star-clouds properly called
nebulae. There may be small clouds of the same