Hipparchus does not mention comets, whence it has been conjectured he had never seen any; it has also been suggested, that he considered them with meteors, which are not objects of astronomical observation. He divided the heavens into forty-nine constellations, viz., twelve in the ecliptic, twenty-one in the north, and sixteen in the south. To one of these he gave the name of Berenice’s Hair, in honour of the wife of Ptolemy Soter, who had consecrated her hair, which was very beautiful, to Venus Urania, if her husband should return from a war in Asia victorious; it being hung up in the temple of the goddess, soon after disappeared, and is said to have been carried off by the gods. Hipparchus likewise constructed a sphere, or celestial globe, on which all the stars visible at Alexandria were depicted; and thought to have been similar to the Faranese globe at Rome, still extant. In his observations on the stars, he discovered that, when viewed from the same spot, their distance always appeared the same from each other; but he discovered the distance of the moon to be different in various parts of the heavens; for instance, in the horizon and zenith. This he conceived to be owing to the extent of the globe; he, therefore, contrived a method of reducing appearances of this kind, to what they would be if viewed from the centre of the earth, which is called a parallax; and the discovery of it was of the greatest importance to astronomy. He took this idea from observing that a tree, in the middle of a plain, appeared in different parts of the horizon, when viewed from different situations; so does a star appear in the various points of the heavens, when viewed in different parts of the globe. Hipparchus was the first who connected geography with astronomy, and this fixed both the sciences on certain principles. After the overthrow of the Roman empire, the first encourager of learning was Charles the Great, or Charlemagne; but little could be done in his time; after his death the former ignorance prevailed. Beda, or Bede, from his piety and modesty termed _venerabilis_, and his scholar, Alcinius, both Englishmen, greatly excelled in general literature; among other qualifications they were eminent in the astronomy of the preceding period. The first step towards the revival of knowledge, or the translation of the Astronomical Elements of Alfergan, the Arab, by order of Frederick II., chosen Emperor of Germany in 1212. About the same time Alphonso X., King of Castile, assembled from all parts the most famous astronomers, who at his desire, composed what are called the Alphonsine Tables, founded on the hypothesis of Ptolemy.