THOMSON. — THE FALL OF A METEORITE. 733 



rections than along the line joining them. This crushing would result 

 in two streams or jets of material rushing out in diametrical directions 

 at velocities of a great range of magnitudes, and they might in some 

 cases, but not in all, be violent enough to produce very high tempera- 

 tures and consequent vaporization. Each body so disrupted would then 

 pursue its way no longer a spherical body but as a new-born spiral neb- 

 ula, the internal forces of which would again set to work to gather up 

 what matter remained outside of that widely dispersed in space. Thus 

 new solar systems would be born from the wreck of those preceding. 

 This involves a modification of the time-honored nebular hypothesis of 

 La Place and is in line with the ideas of Chamberlin and Moulton in 

 their planetesimal hypothesis. 



We are led to suspect that this is indeed the process of nature, a pro- 

 cess which has gone on from an infinite or indefinite past and which 

 will continue as long as a ray of light gan traverse the ether of space. 

 To me the idea that the universe is like a clock running down is repug- 

 nant. Even though uranium, radium, thorium are disintegrating grad- 

 ually, and we have no evidence of their generation by any process, there 

 may be some source, as under the enormous pressures within a large 

 orb, where such elements and perhaps others of still higher atomic weight 

 and greater instability arise. Here again the law of survival holds, the 

 electrons in the atom having unstable orbits being cast out in reducing 

 the body to simpler and more stable forms, just as in the solar system 

 the erratic comets must be eventually swallowed up and lost. 



