120 



BRUSH— DISCUSSION OF 



[April 24, 



after a rapidly subsiding series of quicker and quicker oscillations it 

 will subside, probably in the course of two or 

 three years, into a globular star of about the 

 same mass, heat and brightness as our present 

 sun." 



Undoubtedly this is a substantially correct 

 description of what would happen under the con- 

 ditions named. The two cold bodies would ac- 

 quire from some source external to themselves 

 the vast energy represented by the heat of the 

 sun, heat sufficient to maintain the enormous 

 solar radiation millions of years without sensible 

 diminution. And this vast accumulation of 

 energy would occur in half a year, largely in the 

 last fezv days before collision. There is, to me, 

 no conceivable source of this energy other than 

 the ether. It may be argued that the two cold 

 bodies, as a gravitating system, initially pos- 

 sessed all this energy in the form of " potential 

 energy of position." This is a most convenient 

 expression, but it affords no explanation of the 

 source of the energy until, as I pointed out at 

 the Washington meeting, we take the energy- 

 endowed ether into partnership as an essential 

 part of the system. Certainly the energy could 

 not be resident in the two cold motionless globes. 

 For a homely illustration, think of two golf balls 

 joined by a stretched thread of rubber ; they form 

 an attracting system and possess " potential 

 energy of position " or separation, but the en- 

 ergy does not reside in the balls, it is in the 

 stretched rubber thread. 



Later in his description Lord Kelvin says: 

 " If, instead of being at rest initially, . . . each 

 globe had a transverse velocity of three quarters 

 (or anything more than .71) of a kilometer per 



second, they would just escape collision, and would revolve in ellipses 



Fig. I. 



