485:82 A similar explanation is given in the Bhágavata, Váyu, and Matsya Puráńas; and like accounts from astronomical writers are cited by Mr. Colebrooke, As. Res. vol. IX. p. 358. The commentator on the Bhágavata thus explains the notion: "The two stars (Pulaha and Kratu) must rise or be visible before the rest, and whichever asterism is in a line south from the middle of those stars, is that with which the seven stars are united; and so they continue for one hundred years." Col. Wilford has also given a like explanation of the revolution of the Rishis; As. Res. vol. IX. p. 83. According to Bentley the notion originated in a contrivance of the astronomers to shew the quantity of the precession of the equinoxes. "This was by assuming an imaginary line or great circle passing through the poles of the ecliptic and the beginning of the fixed Maghá, which circle was supposed to cut some of the stars in the Great Bear. The seven stars in the Great Bear the circle so assumed was called the line of the Rishis, and being fixed to the beginning of the lunar asterism Maghá, the precession would be solved by stating the degree &c. of any moveable lunar mansion cut by that fixed line or circle as an p. 486 index. Historical View of Hindu Astronomy, p. 65.