average reader, while others are well known; but all possess the
fascination of whatever is strange, marvelous, obscure, or mysterious
-- magnified, in this case, by the portentous scale of the phenomena.

The idea of the author is to tell about these things in plain
language, but with as much scientific accuracy as plain language will
permit, showing the wonder that is in them without getting away from
the facts. Most of them have hitherto been discussed only in technical
form, and in treatises that the general public seldom sees and never
reads.

Among the topics touched upon are:
* The strange unfixedness of the ``fixed stars,'' the vast
migrations of the suns and worlds constituting the universe.
* The slow passing out of existence of those collocations of stars
which for thousands of years have formed famous
``constellations,'' preserving the memory of mythological heroes
and heroines, and perhaps of otherwise unrecorded history.
* The tendency of stars to assemble in immense clouds, swarms, and
clusters.
* The existence in some of the richest regions of the universe of
absolutely black, starless gaps, deeps, or holes, as if one were
looking out of a window into the murkiest night.
* The marvelous phenomena of new, or temporary, stars, which appear
as suddenly as conflagrations, and often turn into something else
as eccentric as themselves.
* The amazing forms of the ``whirlpool,'' ``spiral,'' ``pinwheel,''
and ``lace,'' or ``tress,'' nebulæ.
* The strange surroundings of the sun, only seen in particular
circumstances, but evidently playing a constant part in the daily