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HISTORICAL VIEW OF THE

the science to its just estimation, and of perfectingwhat his predecessors had left unfinished, he felt thenecessity of collecting the materials existing in theworks of Hipparchus and others into a regular system,and combining these with his own investigations, so asto form a complete body of astronomy. This gave rise tohis great work entitled Mc-yockri 2v»ra|i; (Great System),the publication of which forms an epoch in the historyof science. This work, becoming known throughoutthe East, was preserved there, and survived the barba-rism of the middle ages. It formed the basis of theastronomy of the Arabians, and, for a considerable time,of modern Europe also: from the former it obtainedthe title of “ Almagest, ” by which it was afterwardsknown in Europe .

Comprehensive as was the design, and elaborate theexecution, of this work, it labours under one cardinaldefect,—the adoption of that view of the system of theworld, which makes the earth the centre, and supposesthe sun and planets to revolve round it. We havealready remarked that there was little in point of realargument from facts, to decide the judgment of theancient astronomers on this point; yet it is difficult toconceive that the arguments from probability, analogy,and simplicity, should not have preponderated with allwho were imbued with any thing like a philosophic spirit.

Ptolemy , however, argued against the solar system.He reiterated the already refuted objection of parallax;and reasoned upon the false and gratuitous theories ofthe peripatetics about motion; contending that, if theearth were really in motion, it ought to leave behind itall the loose bodies upon its surface, which (accordingto their theory), as being lighter, must move moreslowly. This, and many equally absurd arguments, headduced; though he admitted that the Pythagorean system possesses much greater simplicity.

We have before mentioned the theory of the epicycles,to account for the planetary motions: these were adoptedby Ptolemy in their full extent. It has been contended