n his neighbors, with which to measure double stars. If he
could not get such an instrument, he measured the positions of the stars
with a transit circle. Then came astrophysics, including photography,
spectroscopy and photometry. The study of the motion of the stars along
the line of sight, by means of photographs of their spectra, is now the
favorite investigation at nearly all the great observatories of the
world. The study of the surfaces of the planets, while the favorite
subject with the public, next to the destruction of the earth by a
comet, does not seem to appeal to astronomers. Undoubtedly, the only way
to advance our knowledge in this direction is by the most powerful
instruments, mounted in the best possible locations. Great astronomers
are very conservative, and any sensational story in the newspapers is
likely to have but little support from them. Instead of aiding, it
greatly injures real progress in science.

There is no doubt that, during the next half century, much time and
energy will be devoted to the study of the fixed stars. The study of
their motions as indicated by their change in position was pursued with
great care by the older astronomers. The apparent motions were so small
that a long series of years was required and, in general, for want of
early observations of the precise positions of the faint stars, this
work was confined mainly to the bright stars. Photography is yearly
adding a vast amount of material available for this study, but the
minuteness of the quantities to be measured renders an accurate
determination of their laws very difficult. Moreover, we can thus only
determine the motions at right angles to the line of sight, the motion
towards us or from us being entirely insensible in this way. Then came
the discovery of the change in the spectrum when a body was in motion,
but still this change was so small that visual observations of it proved
of but little value. Attaching a carefully constructed spectroscope to
one of the great telescopes of the world, photographing the spectrum of
a star, and measuring it with the greatest care, provided a tool of
wonderful efficiency. The motion, which sometimes amounts to several
hundreds of miles a second could thus be measured to within a fraction
of a mile. The discovery that the motion was variable, owing to the
star's revolving around a great dark planet sometimes larger than the
star, added greatly not only to the interest of these resea