16 KKOM NEBULA TO NEBULA 



to contradict this view. Hud the question remained 

 simply that of explaining the phenomena, the discovery 

 of the elliptidty of the. paths of planets might have 

 been mwle then and there, and both Copernicus and 

 Kepler been anticipated by many centuries. Unfor- 

 tunately, the metaphysical deduction as to the per- 

 fection of the circle, and the anthropocentric and geo- 

 centric ideas of that age, were too deeply rooted in the 

 minds of the ancient philosophers to allow conflicting 

 thoughts to enter. Ptolemy sought to harmonize fact 

 with fancy by the device of imagining the planet to be 

 traveling around in a small circle while the center 

 of that circle was simultaneously describing the main 

 circle or orbit forming to it a sort of scalloped 

 border, as it were. But he soon found that one 

 such imaginary superimposed cycle did not suffice, so 

 he added another supplementing the first, then still 

 another supplementing the second, and so on, until the 

 final design, when sketched, became absolutely meaning- 

 less. These superadded circles bear the general name 

 of epicycles. 



Such was the state of the science of astronomy dur- 

 ing the fourteen centuries immediately preceding the 

 advent of Xicholaus Copernicus (1473-1543). To this 

 man it seemed preposterous that the whole universe, 

 whose immensity was then beginning to be compre- 

 hended, should be assumed, quite ns a matter of course, 

 to be doing homage to such a grain of sand as our earth. 

 Accordingly, he brought out his celebrated work, lie 

 Orlnutn Coclestrurn Revolutiombus, which is founded 

 upon the principle (note its simplicity) that the uni- 

 verse only <7/>/)rY/r\ to be circulating around us, because 

 our little earth is turning on its axis that it is our 

 train, and not the scenery without, that is really in 

 motion. This bit of common sense nearly cost Coper- 



