566 Scientific Proceedings, Royal Dublin Society. 



separation of the particles, we may ask, what force can have acted 

 between particles sundered by infinite distance ? The gravitational 

 force falling off as the square of the distance, must vanish at 

 infinity if we mean what we say when we ascribe infinite separa- 

 tion to them. Their condition is then one of neutral stability, a 

 finite movement of the particles neither increasing nor diminishing 

 interaction. They had then remained eternally in their separated 

 condition, there being no cause to render such condition finite. 

 The difficulty involved here appears to me of the same nature as 

 the difficulty of ascribing any residual heat to the sun after eternal 

 time has elapsed. In both cases we are bound to prolong the 

 time, from our very idea of time, till progress is no more, when 

 in the one case we can imagine no mutual approximation of the 

 particles, in the other no further cooling of the body. However, 

 I will not dwell further upon this objection, as it does not, I 

 believe, present itself with equal force to every mind. A reason 

 less open to dispute, as being less subjective, against the aggre- 

 gation of infinitely remote particles as the origin of our universe, 

 is contained in the " physical " objection. 



In this objection we consider that the appearance presented 

 by our universe negatives the hypothesis of infinitely prolonged 

 aggregation. We base this negation upon the appearance of 

 simultaneity presented by our universe, contending that this 

 simultaneity is contrary to what we would expect to find in the 

 case of particles gathered from infinitely remote distances. Whe- 

 ther these particles were endowed with relative motions or not is 

 unimportant to the consideration. In what respects do the phe- 

 nomena of our universe present the appearance of simultaneous 

 phenomena ? We must remember that the suns in space are as 

 fires which brighten only for a moment and are then extinguished. 

 It is in this sense we must regard the longest burning of the stars. 

 Whether just lit or just expiring counts little in eternity. The 

 light and heat of the star is being absorbed by the ether of space 

 as effectually and rapidly as the ocean swallows the ripple from 

 the wings of an expiring insect. Sir William Herschel says of 

 the galaxy of the milky way : — " We do not know the rate of 

 progx-ess of this mysterious chronometer, but it is nevertheless 

 certain that it cannot last for ever, and its past duration cannot 

 be infinite." We do not know, indeed, the rate of progress of the 



