he northern sky in such a position as the stars may happen to be.
The Great Bear, or Dipper, will be seen at nine o'clock in the
evening above the pole in April and May; west of the pole, the
Pointers downward, in July and August; close to the north horizon
in October and November; and east of the pole the Pointers highest,
in January and February. The names of such constantly visible stars
should be familiar. In order, from the end of the tail of the Great
Bear, we have Benetnasch ae, Mizar z, Little Alcor close to it,
[Page 198] Alioth, e Megrez, d at the junction, has been growing
dimmer for a century, Phad, g Dubhe and Merak. It is best to get
some facility at estimating distances in degrees. Dubhe and Merak,
"the Pointers," are five degrees apart. Eighteen degrees forward of
Dubhe is the Bear's nose; and three pairs of stars, fifteen degrees
apart, show the position of the Bear's three feet. Follow "the
Pointers" twenty-nine degrees from Dubhe, and we come to the
pole-star. This star is double, made of two suns, both appearing as
one to the naked eye. It is a test of an excellent three-inch
telescope to resolve it into two. Three stars beside it make the
curved-up handle of the Little Dipper of Ursa Minor. Between the two
Bears, thirteen degrees from Megrez, and eleven degrees from Mizar,
are two stars in the tail of the Dragon, which curves about to
appropriate all the stars not otherwise assigned. Follow a curve of
fifteen stars, doubling back to a quadrangle from five to three
degrees on a side, and thirty-five degrees from the pole, for his
head. His tongue runs out to a star four degrees in front. We shall
find, hereafter, that the foot of Hercules stands on this head. This
is the Dragon slain by Cadmus, and whose teeth produced such a crop
of sanguinary men.

The star Thuban was once the pole-star. In the year B.C. 2300 it
was ten times nearer the pole than Polaris is now. In the year
A.D. 2100 the pole will be within 30' of Polaris; in A.D. 7500,
it will be at a of Cepheus; in A.D. 13,500, within 7 deg. of Vega; in
A.D. 15,700, at the star in the tongue of Draco; in A.D. 23,000,
at Thuban; in A.D. 28,000, back to Polaris. This indicates no change
in the position of the dome [Page 199] of stars, but a change in the
direction of the axis of the earth pointing to these various places
as the cycles pass. As the earth goes round its orbit, the axis,
maintaining nearly the same direction, really points to every p