THE NEW COSMOLOGY 



Saturn, and then suddenly to an incomparably greater 

 sphere, to which also we must ascribe a complete rota- 

 tion in twenty-four hours. If, however, we assume a 

 motion of the earth, the rapidity of the periods is very 

 well preserved; from the slowest sphere of Saturn we 

 come to the wholly motionless fixed stars. We also 

 escape thereby a fourth difficulty, which arises as soon 

 as we assume that there is motion in the sphere of the 

 stars. I mean the great unevenness in the movement 

 of these very stars, some of which would have to re- 

 volve with extraordinary rapidity in immense circles, 

 while others moved very slowly in small circles, since 

 some of them are at a greater, others at a less, distance 

 from the pole. That is likewise an inconvenience, for, 

 on the one hand, we see all those stars, the motion of 

 which is indubitable, revolve in great circles, while, on 

 the other hand, there seems to be little object in plac- 

 ing bodies, which are to move in circles, at an enormous 

 distance from the centre and then let them move in 

 very small circles. And not only are the size of the 

 different circles and therewith the rapidity of the move- 

 ment very different in the different fixed stars, but the 

 same stars also change their orbits and their rapidity 

 of motion. Therein consists the fifth inconvenience. 

 Those stars, namely, which were at the equator two 

 thousand years ago, and hence described great circles 

 in their revolutions, must to-day move more slowly and 

 in smaller circles, because they are many degrees re- 

 moved from it. It will even happen, after not so very 

 long a time, that one of those which have hitherto been 

 continually in motion will finally coincide with the 

 pole and stand still, but after a period of repose will 



