1 66 THE WORLD MACHINE 



a sphere is the most perfect form," &c., which is characteristic 

 of Aristotle and the ancients. But it bore no trace of that 

 errant-minded mysticism from which even Kepler in the next 

 century had not freed himself. 



For the rest, it is written in such a straightaway, calmly 

 confident manner that, knowing how nowadays, and in the old 

 days too, successive works of science are as a rule little more 

 than compilations from some previous work, you might readily 

 suppose a high state of astronomical science in his time. We 

 know, of course, that it was full of the wildest fancies, that 

 almost anybody's guess found credulous attention. 



Despite the faint-hearted preface inserted by other hands, 

 Coppernicus does not in the least put forward his ideas as a 

 mere hypothesis. He believes in them serenely, proves them 

 to his own satisfaction, and, more curious still, for any alterna- 

 tive suggestions has only the scantiest word. He does not 

 sketch out the old Ptolemaic ideas so long in vogue ; he goes 

 straight to his task. First of all, the world that is, the whole 

 cosmos is a sphere. This takes only ten lines to prove. The 

 sphere is the most perfect form. It is evident that the heavenly 

 bodies are spherical, just like a drop of water, therefore the 

 heavens too must be spherical. 



This is logic that limps, and, coming on the earliest page, 

 it gives you an unfavourable impression. It is almost the 

 weakest point in the whole book. In the next chapter he details 

 all the familiar reasons to prove that the earth is likewise a 

 sphere. He points to the discovery of America as further proof, 

 and it is evident that this central fact .had taken a strong hold 

 upon his mind. 



In another section he goes on to prove that the motion of 

 all heavenly bodies must be in a circle. We know he was 

 wrong here, but in this assumption he dismissed the clumsy 

 system of epicycles of Hipparchus and Ptolemy. Then he 

 plunges abruptly into the question of the motion of the earth. 

 Since it has been shown that the earth has the form of a globe, 

 it is now in order to inquire whether, from this fact, it does not 

 also possess a motion ; likewise what place it occupies in the 

 universe^. Most writers, he says, agree that the earth is the 

 middle point of the world, and find any other suggestion not 

 only inconceivable but laughable. Coppernicus does not. He 

 has been pondering the matter for forty years, and has set 



