HISTORY OF ASTRONOMY. 3g

motion of the Stars had been accounted for byan hypothefis of this kind, it rendered the theoryof the heavens more uniform, to account for thatof the Sun and Moon in the fame manner. Thefphere of the Sun they placed above that of theMoon ; as the Moon was evidently feen in ecliplesto pals betwixt the Sun and the Earth. Each ofthem was fuppofed to revolve by a motion of itsown, and at the fame time to be a fleeted by themotion of the Fixed Stars . Thus, the Sun wascarried round from çaft to weft by the communi-cated movement of this outer lphere, which pro-duced his diurnal revolutions, and the vieilli tudesof day and night ; but at the fame time he hada motion of his own, contrary to this, from weftto eaft, which occalioned his annual revolution,and the continual Uniting of his place with regardto the Fixed Stars . This motion was more, eafy,they thought, when carried on edgeways, andnot in direfl: opposition to the motion of the outerfphere, which occasioned the inclination of theaxis of the fphere of the Sun, to that of the fphere ofthe Fixed Stars ; this again produced the obliquityof the ecliptic, and the consequent changes of theseasons. The moon, being placed below the fphereot the Sun, had both a shorter course to finish,and was less obftrutfted by the contrary movementof the fphere of the Fixed Stars , from which sitewas farther removed. She finished her period,therefore, in a shorter time, and required but amonth, instead of a year, to complétait.