184 ON THE ORIGIN OF TIIE PLANETARY SYSTEM. 



which characterises larger masses. 1 The moon, on the 

 contrary, exhibits formations on its surface which are 

 strikingly suggestive of volcanic craters, and point to 

 a former state of ignition of our satellite. The mode 

 of its rotation, moreover, that it always turns the 

 same side towards the earth, is a peculiarity which 

 might have been produced by the friction of a fluid. 

 At present no trace of such a one can be perceived. 

 You see, thus, by what various paths we are con- 

 FIG ]2 stantly led to the same 



primitive conditions. 

 The hypothesis of Kant 

 and Laplace is seen to 

 be one of the happiest 

 ideas in science, which 

 at first astounds us, and 

 then connects us in all 

 directions with other dis- 

 coveries, by which the 

 conclusions are confirmed until we have confidence in 

 them. In this case another circumstance has con- 

 tributed that is, the observation that this process of 

 transformation, which the theory in question presup- 

 poses, goes on still, though on a smaller scale, seeing 



1 Mr. Zoellner concludes from photometric measurements, which, 

 however, need confirmation, that Jupiter still possesses a light of iis 

 own. 



