THE NEW COSMOLOGY 



in favor of the earth's motion. When we merely 

 consider the immensity of the starry sphere in com- 

 parison with the smallness of the terrestrial ball, which 

 is contained many million times in the former, and then 

 think of the rapidity of the motion which completes a 

 whole rotation in one day and night, I cannot persuade 

 myself how any one can hold it to be more reasonable 

 and credible that it is the heavenly sphere which ro- 

 tates, while the earth stands still. 



" Simplicio. I do not well understand how that pow- 

 erful motion may be said to as good as not exist for the 

 sun, the moon, the other planets, and the innumerable 

 host of fixed stars. Do you call that nothing when 

 the sun goes from one meridian to another, rises up 

 over this horizon and sinks behind that one, brings 

 now day, and now night ; when the moon goes through 

 similar changes, and the other planets and fixed stars 

 in the same way ? 



" Salviati. All the changes you mention are such only 

 in respect to the earth. To convince yourself of it, only 

 imagine the earth out of existence. There would then 

 be no rising and setting of the sun or of the moon, no 

 horizon, no meridian, no day, no night in short, the 

 said motion causes no change of any sort in the rela- 

 tion of the sun to the moon or to any of the other 

 heavenly bodies, be they planets or fixed stars. All 

 changes are rather in respect to the earth ; they may all 

 be reduced to the simple fact that the sun is first visible 

 in China, then in Persia, afterwards in Egypt, Greece, 

 France, Spain, America, etc., and that the same thing 

 happens with the moon and the other heavenly bodies. 

 Exactly the same thing happens and in exactly the 



VOL. II. 7 S 



