An historical survey of the astronomy of the ancients 12+

📓 This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1862 Excerpt: ...but is an appreciable distance, with reference to the distance of the fixed stars. For example, he argues that if the earth were upon the axis of the celestial sphere, but were nearer one pole than the other, the horizon would cut the visible heaven into unequal parts in every latitude where the sphere is oblique. (160) His refutation of the hypothesis of the earth having a motion of translation, is exclusively founded on his refutation of the hypothesis of the earth being motionless at a point not coincident with the centre of the celestial sphere. It is not at all directed against the movement of the earth: it is confined to the proof that the earth cannot be at any place other than the centre of the heaven; which must happen, if it has a motion of translation. Ptolemy simply mentions the hypo (159) i. 5. (160) i. 4. thesis, without specifying the nature of the supposed movement, and without attributing the hypothesis to Aristarchus or any other astronomer. He proceeds to remark, that some persons admit the force of these objections to the hypothesis of a movement of translation, but conceive that they propound a theory, both probable and free from objection, if they suppose the heaven to be immovable, and the earth to revolve round the celestial axis from west to east...