io6 THE WORLD MACHINE 



" Felix qui potuit rerum cognoscere causas ! " 



So Virgil sings ; life has no purer joy. Yet whosoever was 

 this first, the lips of history are mute. Some king's " magician," 

 or soothsayer of the Nile, perhaps ; no mighty cenotaphs im- 

 mortalise his name ; not for such as he do a hundred thousand 

 burdened slaves sweat and grunt through thirty years to rear 

 a tomb. 



For that matter, there may have been no one. Great con- 

 ceptions, great discoveries, have no Minervan birth. So, here 

 and there among the old Greeks, we find men who seem to have 

 caught sight of the idea, but did not " see it clearly and see it 

 whole." Thus old Hicetas of Syracuse, or Nicetas, as Cicero 

 calls him Cicero's account, doubtless, was not very accurate, 

 for Cicero was a literary man ; it may quite misrepresent. But 

 Hicetas, he says, pictured the earth as " turning and twisting 

 on its axis while all else in the heavens stands still." Quaint 

 and ingenious thought. In another century a great Alexandrian 

 will take out the twist, and thus, away back there, work out in 

 all its essentials our modern welt-anschauung. 



But the proposal to give the earth not only a rotatory but 

 a translatory motion as well, drove against a simple but very 

 formidable obstacle. That was the dislocation which two 

 bodies our two peaks from the Matterhorn, for example 

 seem to undergo when we change our point of view. If the 

 sun be at an enormous distance from the earth, and the earth 

 goes round it, then from one side of the circle to the other we 

 shall view the stars from two enormously separated points. 

 Some of the stars must appear to shift their position one to 

 another if this be true. 



No one could find the slightest change in the stellar sphere. 

 Alone the sun and planets moved. 



True if one could think, with Eudoxus, that the stars were 

 set in the face of a solid sphere, so all would be at an equal dis- 

 tance, there would be no difficulty. But it was clear that the 

 planets were widely ranged in space ; the eclipses left no doubt 

 of that; their brilliancy suggested the same. There was the 

 same varied brilliance among the unmoving stars ; they differed 

 from the almost planet's glow of Sirius and Arcturus to the 

 faintest gleams. 



There was one escape, and one alone. That was to conceive 

 the fixed stars as so remote from all mundane relations that, 



