Page 304 - Third Book of Reading Lessons

READING LESSONS. 303
1. THE reasons which are now adduced in proof of the spherical gure of the earth, are so simple, and the principles on which they are based, so evident, that it is astonishing how the ancients could remain so long jgnorant of this ct. The opinions of those among !hem who imagined it to be cylindrical, qr in the rm of a drum, approached nearest to the truth; but the general notion was, that the earth was a vast extended plain, bounded by the ocean. This, per­ haps, is the idea which every common observer would rm. The more attentive inquirer will, how­
ever, easily perceive the visible e ects of the globu­ lar rm of the earth om the llowing appearances. A person on shore can see the masts and rigging of a vessel at sea, when the hull is entirely concealed by the convexity of the water. As the vessel ap­ proaches the place of observation, she seems as if ascending a gentle acclivity, and the contrary appear­ ance takes place as she recedes om the shore. The phenomena will be precisely the same to a person on board, with regard to the objects on land; and this occurring in every part of the world, no matter what may be the bearing of the objects, or . the course of the vessel, it obviously llows, that the gure of the earth must be that of a sphere or globe, as these ob­ servations cannot be reconciled with any other rm whatever.
2. The shadow of the earth on the moon, as seen at the lunar eclipses, being always, and under all circumstances, circular, strengthens this opinion. Bnt the voyages of those who have actually sailed round the earth, are experimental - proofs of its spherical rm om east to west ; and that it is so om north to south, is mani st om observations made on the polar star, which increases in altit de as we approach