"Nec paribus positæ sunt frontibus; utraque caudam Vergit in alterius rostrum, sequiturque sequentem."[8]
Not in the same direction do they face: The one its tail towards the other's snout Turns, and they thus, pursuing, each pursue.
Certain it is that the Phœnicians, as experienced seamen, would guide their course by the constellation lying nearest to the pole. But was this constellation the same which we now-a-days call Ursa Minor? It is quite allowable for us to put such a question, because everybody knows that, owing to the movement of the terrestrial axis around the poles of the ecliptic, the axis of the world (the terrestrial axis prolonged) is displaced to an extent which becomes perfectly appreciable at the end of a certain time.[9] We may calculate, therefore, that the pole, now situated, as we have already said, near the star Polaris (α in Ursa Minor), was formerly at some distance from it. So, at the epoch of the greatest prosperity of the Phœnician people, or about three thousand years ago, the north pole would nearly correspond with a star in Draco, now 24° 52' distant.
[This constellation is shown in fig. 2, between Ursa Major and Ursa Minor; the α in Draco is a star surrounded by a circle, like the Polar Star, α in Ursa Minor.]
That the constellation of Draco was well known to the ancients, we may gather from a passage in the "Phenomena" of Aratus, a work partly translated by Cicero:--
"The Dragon, like the sinuous course of a river, uncoils his long scaly body, and surrounds with undulating folds the two constellations of Ursa Major and Ursa Minor."
Bringing together these different facts for the sake of comparison, we arrive at the conclusion that the Polar Star, by whose scintillating light the early mariners steered their tiny keels, was not the Polaris of to-day--α in Ursa Minor--but α in the constellation of the Dragon.
The Arabs, those navigators of the Waterless Sea (as they poetically designate the desert of Sahara), have bestowed particular appellations on several stars; but they guide themselves rather by their radiance than by their position. Thus, such stars as α Draco, α Cepheus, α Cygnus, which have occupied, and, in the course of centuries, will again occupy the place of Polaris, have received no special denomination; while the stars of Ursa Major, α and β (occupying the posterior angles of the chariot), are called Dubke and Merak;[10] γ, δ, ε, ζ, η, which follow in due succession--Phegæa, or Phad, Megrez, Alioth, Mizar, and Ackaïr, or Benetnasch. Certain stars in the same constellation, which are barely visible, have also received distinctive names: such is Alcor, a star between the fifth and sixth magnitude, in the tail of Ursa Major, between Mizar and Benetnasch. This star, it is true, had a special use: it served the Arabs as the test of a good eyesight.