Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-01-06

instrument adapted for ticking photo-
graphs OF the spectra Of celestial bodies
ana is due 10 the power which that instru-
ntent mas OF revealing a motion of an
pt' ach or recession In a star through a
slight displacement which such motion
causes in the spectral lines
Prof Campbelrs list of discoveries of
inns sort already embraces fifteen stars #
which the most Interesting is Poiaris or the
North star. This star has been found 10
be moving toward us but with a Velocity
Which varies in such way as to Indicate
that II is associated with al least two in
Visible companions. with one Of which II
forms binary system, the two bodies re-
Volving about their common center of
gravity In a period of about four DAYS
while this pair revolves about tho third
body. In a period not yet determined hut
which appears to have length of many
years.
Variable Velocity.
Another and equally interesting case Of
variable velocity in the line Of sight is
afforded by the brilliant star CapeIa. An
examination of six spectrum plates OF "a
pella leaves no doubt" says Prof Camp
bell, that this star is probably. like Po-
laris. a spectroscopI2 binary" The com
panion body is dark. The period of r,,o-
luton has not yet been determined, hut 1t
would appear to be some ten or twelve
months in length. There are Indications
also OF a second companion, which is utn-
nous. revolving in much shorter period,
not yet determined. 1t is interesting To re-
call here that a few years ago 1t WAS dis
covered at the Harvard College observatory
tHat Beta Aurigae. the second ma gnitude
star in the right shoulder of the Wagner
CapeIa is in the left-is "spectroScnpic
binary" the companion star being bright
but too close to the principal star Ia ice Wis
ible through telescope. The period Of
revolution in this case Is four days.
Other interesting stars on Prof. Camp
bells list are: Epsilon trsae MINORS. the
| ID.
the Little Dipper; Eta Pegasi. star of the
third ma gnitude near the northwest corner
of the Square" Epsilon Llbrac, in the
northern pan of the Balance and Beta Cap
ricorni the lower of the conspicuous pair
OF stars which mark the horns of Capri
corn.
The great interest which attaches to these
discoveries lies in the fact that the dark
bodies thus revealed must be bodies Of con-
siderable size in order to swing, as they do.
the stars-the suns-with which they are
associated. They can be nothing else than
extinct suns not mere planetary bodies.
They seem to be fairly numerous to judge
from the number already discovered. We
may regard them Illustrations of the
fate which awaits our own glorious lum-
mary, some millions Of years hence.
The Planets.
Mercury is a morning star, but is too near
the sun to be visible
Venus is an evening star, setting shortly
before O'Clock. Visible low in the south
west.
Mars Will be evening star. though not
visible. until the 10th Of the month, and
after that date morning star
Jupiter. three hours west of the sun. is
now visible in the southeast as a morning
star.
Saturn and Uranus, between Jupiter ana
the sun, are both morning stars.
Neptune is an evening star, the only
planet now above the horizon at PM.
about six degrees due east of the star which
tips the southern horn Of Taurus.
At | am. Washington time. on the ID OF
this month the earth was in perihelion-at
its nearest to the