68 THE WORLD MACHINE 



the light, of one obscure problem was the illumination of the 

 other. The linking of fact to fact which revealed the mechanism 

 of the changing lengths of the day brought with it the proof 

 of a spheroidal earth. It must, too, have set men thinking 

 out the mechanism of the seasons as well. It certainly accus- 

 tomed the mind to the idea that the blazing ball which daily 

 sweeps through its circle in the heavens is in reality a body 

 colossal in its dimensions and therefore fixed at an enormous 

 distance. It was among the first of these splendid flights of 

 the imagination which have characterised all scientific advance ; 

 it was among the earliest of these difficult conquests over appear- 

 ances upon which all progress of knowledge depends ; it was 

 among the first-fruits of that endeavour to introduce mechanical 

 conceptions into the explanation of phenomena, upon which all 

 science is based. 



Not without a tinge of melancholy will the student of history 

 take note of the date ; that among the freest people of antiquity, 

 at near two thousand years before Columbus stood disputing 

 with the wise men before Ferdinand and Isabella, there were 

 thinkers who had made the first steps toward a correct know- 

 ledge of the earth, and from whom the superstitions of the 

 vulgar, like an outworn mantle, had been cast away. 



Whether all this had been done by the priests of Isis or 

 the servitors of Bel, still two thousand years further back, we 

 do not know. Among the pyramid-builders of Egypt a high 

 level in both astronomy and mathematics had been attained. 

 The truly marvellous geometrical construction of Cheops is 

 proof of that. Its edges are the four points of the compass, 

 determined with astonishing precision, and from the royal 

 burial-chamber, in the far depths of the Pyramid, through the 

 long inclined tunnel which leads to the entrance, a mirror 

 kept ceaseless vigil with the polar star. There is little reason 

 to suppose that the genial brain which planned that mightiest 

 of human tombs differed in any appreciable degree in either 

 its capacity or its scientific knowledge from Archimedes or 

 Newton. Men who could thus observe and thus build must 

 have been reasoners as well. But if any one among them had 

 drawn the figure of Bion, the sands of the desert cover it as 

 they cover him. 



Until that figure had been drawn, or until such a train of 

 reasoning had been followed out, men's ideas about this earth 



