266 DISCOURSE ON THE STUDY 



earth. By thus drawing a broad and impassable line 

 of separation between celestial and terrestrial me- 

 chanics, it placed the former altogether out of the 

 pale of experimental research, while it at the same 

 time impeded the progress of the latter by the as- 

 sumption of principles respecting natural and un- 

 natural motions, hastily adopted from the most 

 superficial and cursory remark^ undeserving even 

 the name of observation. Astronomy, therefore, con- 

 tinued for ages a science of mere record, in which 

 theory had no part, except in so far as it attempted 

 to conciliate the inequalities of the celestial motions 

 with that assumed law of uniform circular revolution 

 which was alone considered consistent with the per- 

 fection of the heavenly mechanism. Hence arose 

 an unwieldy, if not self-contradictory, mass of hypo- 

 thetical motions of sun, moon, and planets, in circles, 

 whose centres were carried round in other circles, 

 and these again in others without end, " cycle on 

 epicycle, orb on orb," till at length, as observation 

 grew more exact, and fresh epicycles were continually 

 added, the absurdity of so cumbrous a mechanism 

 became too palpable to be borne. Doubts were ex- 

 pressed, to which the sarcasm of a monarch * gave a 

 currency they might not have obtained in a period 

 when men scarcely dared trust themselves to think ; 

 and at length Copernicus, promulgating his own, or 

 reviving the Pythagorean doctrine, which places 

 the sun in the centre of our system, gave to astro- 

 nomy a simplicity which, contrasted with the com- 

 plication of the preceding views, at once commanded 

 assent. 



* Alphonso of Castile, 1252. 



