ed to it that astronomers have had no hesitation in
identifying it as the hypothetical body whose existence Bessel had
correctly surmised.

[Illustration: FIG. 5.--Apparent Orbit of the Companion of Sirius.

(_Drawn by Mr. Burnham._)]

The Sirian satellite is a yellow star of the eighth magnitude, and
shines with a feeble light when contrasted with the surpassing
brilliancy of its neighbour.

Astronomers were for some time in doubt as to whether the uneven motion
which characterised the path of Sirius could be ascribed to the
attraction of its obscure attendant, which presented such a marked
contrast to its primary, and several observers were inclined to believe
that the disturbing body still remained undiscovered. When, however, the
density of the lesser star became known, it was discovered that, weight
for weight, that of Sirius exceeded it only in the proportion of two to
one, though as a light-giver the great orb is believed to be 5,000 times
more luminous. The Sirian satellite revolves round its primary in about
fifty years, and at a distance twenty-eight times that of the Earth from
the Sun.

The surpassing brilliancy of Sirius as compared with that of the other
stars of the firmament has rendered it at all times an object of
interest to observers. The Egyptians worshipped the star as Sothis, and
it was believed to be the abode of the soul of Isis. The nations
inhabiting the region of the Nile commenced their year with the heliacal
rising of Sirius, and its appearance was regarded as a sure forerunner
of the rising of the great river, the fertilising flood of which was
attributed to the influence of this beautiful star. It is believed that
the Mazzaroth in Job is an allusion to this brilliant orb. Among the
Romans Sirius was regarded as a star of evil omen; its appearance above
the horizon after the summer solstice was believed to be associated with
pestilence and fevers, consequent upon the oppressive heat of the
season of the year. The _dies caniculares_, or dog-days, were reckoned
to begin twenty days before, and to continue for twenty days after, the
heliacal rising of Sirius, the dog-star. During those days a peculiar
influence was believed to exist which created diseases in men and
madness among dogs. Homer alludes to the star

'whose burning breath
Taints the red air with fevers, plagues and death.'

Sirius, which is in Canis Major (one of Orion's hunting dogs), i