is concerned, there can be no hesitation. The 500,000,000
incandescent suns in the heavens are eloquent proof of the appalling
heat that is engendered by the collisions of the concentrating
particles.

In general outline we now follow the story of a star with some
confidence. An internal explosion, a fatal rush into some dense nebula
or swarm of meteors, a collision with another star, or an approach
within a few million miles of another star, scatters, in part or whole,
the solid or liquid globe in a cloud of cosmic dust. When the violent
outrush is over, the dust is gathered together once more into a star. At
first cold and attenuated, its temperature rises as the particles come
together, and we have, after a time, an incandescent nucleus shining
through a thin veil of gas--a nebulous star. The temperature rises still
further, and we have the blue-hot star, in which the elements seem to
be dissociated, and slowly re-forming as the temperature falls. After,
perhaps, hundreds of millions of years it reaches the "yellow" stage,
and, if it has planets with the conditions of life, there may be a
temporary opportunity for living things to enjoy its tempered energy.
But the cooler vapours are gathering round it, and at length its
luminous body is wholly imprisoned. It continues its terrific course
through space, until some day, perhaps, it again encounters the mighty
cataclysm which will make it begin afresh the long and stormy chapters
of its living history.

Such is the suggestion of the modern astronomer, and, although we seem
to find every phase of the theory embodied in the varied contents of
the heavens, we must not forget that it is only a suggestion. The
spectroscope and telescopic photography, which are far more important
than the visual telescope, are comparatively recent, and the field to be
explored is enormous. The mist is lifting from the cosmic landscape, but
there is still enough to blur our vision. Very puzzling questions remain
unanswered. What is the origin of the great gaseous nebulae? What is
the origin of the triple or quadruple star? What is the meaning of stars
whose light ebbs and flows in periods of from a few to several hundred
days? We may even point to the fact that some, at least, of the spiral
nebulae are far too vast to be the outcome of the impact or approach of
two stars.

We may be content to think that we have found out some truths, by no
means the whole truth, about the evolution of wor