When we read Chaucer we are transported into a world in which the heavenly bodies and their movements seem to bear a more intimate relation to human life than they do in the world in which we live. The thought of the revolving spheres carrying sun, moon, and planets, regulating light and heat on the earth, and exercising a mysterious influence over terrestrial events and human destiny was a sublime conception and one that naturally appealed to the imagination of a poet. Chaucer was impressed alike by the vastness of the revolving spheres in comparison to the earth's smallness, by their orderly arrangement, and by the unceasing regularity of their appearance which seemed to show that they should eternally abide. In the _Parlement of Foules_ he interpolates a passage from Cicero's _Somnium Scipionis_ in which Africanus appears to the sleeping Scipio, points out to him the insignificance of our little earth when compared with the vastness of the heavens and then admonishes him to regard the things of this world as of little importance when compared with the joys of the heavenly life to come.[9] "Than shewed he him the litel erthe, that heer is, At regard of the hevenes quantite; And after shewed he him the nyne speres." The regular arrangement of the planetary spheres clings often to the poet's fancy and he makes many allusions to their order in the heavens. He speaks of Mars as "the thridde hevenes lord above"[10] and of Venus as presiding over the "fifte cercle."[11] In _Troilus and Criseyde_ the poet invokes Venus as the adorning light of the third heaven.[12] "O blisful light, of which the bemes clere Adorneth al the thridde hevene faire!"[13] Mediaeval astronomers as we have seen, imagined nine spheres, each of the seven innermost carrying with it one of the planets in the order mentioned below; the eighth sphere was that of the fixed stars, and to account for the precession of the equinoxes, men supposed it to have a slow motion from west to east, round the axis of the zodiac; the ninth or outermost sphere they called the _primum mobile_, or the sphere of first motion, and supposed it to revolve daily from east to west, carrying all the other spheres with it. The thought of the two outer spheres, the _primum mobile_, whirling along with it all the inner spheres, and the firmament, bearing hosts of bright stars, seems to have appealed strongly to the poet's imagination. In the _Tale of the Man of Lawe_ the _primum mobile_ is described as crowding and hurling in diurnal revolution from east to west all the spheres that would naturally follow the slow course of the zodiac from west to east.[14] Elsewhere the _primum mobile_ is called the "whele that bereth the sterres" and is said to turn the heavens with a "ravisshing sweigh:"