aversed by a pretty strongly
compressed pair of globes. The truth of this hypothesis can be tested by
close observation of the phases of the star during the next few years.

The variable in the Head of Medusa is the exemplar of a class including
26 recognised members, all of which doubtless represent occulting
combinations of stars. But their occultations result merely from the
accident of their orbital planes passing through our line of sight;
hence the heavens must contain numerous systems similarly constituted,
though otherwise situated as regards ourselves, some of which, like
Spica Virginis, will become known through their spectroscopic changes,
while others, because revolving in planes nearly tangent to the sphere,
or at right angles to the visual line, may never disclose to us their
true nature. Among eclipsing stars should probably be reckoned the
peculiar variables, Beta Lyrae and V Puppis, each believed to
consist of a pair of bright stars revolving almost in contact.[1460]
Three stars, on the other hand, distinguished by rapid and regular
fluctuations, have been proved by Belopolsky to be attended by
non-occulting satellites, which circulate, nevertheless, in the
identical periods of light-change.

Gore's "Catalogue of Known Variables"[1461] included, in 1884, 190
entries, and the number was augmented to 243 on its revision in
1888.[1462] Chandler's first list of 225 such objects,[1463] published
about the same time, received successive expansions in 1893 and
1896,[1464] and finally included 400 entries. A new "Catalogue of
Variable Stars," still wider in scope, will shortly be issued by the
German _Astronomische Gesellschaft_. Mr. A. W. Roberts's researches on
southern variables[1465] have greatly helped to give precision, while
adding to the extent of knowledge in this branch. Dr. Gould held the
opinion that most stars fluctuate slightly in brightness through
surface-alterations similar to, but on a larger scale than those of the
sun; and the solar analogy might be pushed somewhat further. It perhaps
affords a clue to much that is perplexing in stellar behaviour. Wolf
pointed out in 1852 the striking resemblance in character between curves
representing sun-spot frequency and curves representing the changing
luminous intensity of many variable stars. There were the same steep
ascent to maximum and more gradual decline to minimum, the same
irregularities in heights and hollows, and, it may be added, the same