US DISSOLUTION. 



cause an equivalent distribution through space, whatever be 

 the form of the matter. One condition, however, 



essential to the literal fulfilment of this result, must be 

 specified; namely, that the quantity of molecular motion 

 radiated into space by each star in the course of its forma- 

 tion from diffused matter, shall either not escape from our 

 Sidereal System or shall be compensated by an equal quan- 

 tity of molecular motion radiated from other parts of space 

 into our Sidereal System. In other words, if we set out 

 with that amount of molecular motion implied by the exist- 

 ence of the matter of our Sidereal System in a nebulous 

 form; then it follows from the persistence of force, that if 

 this matter undergoes the re-distribution constituting Evo- 

 lution, the quantity of molecular motion given out during 

 the integration of each mass, plus the quantity of molecular 

 motion given out during the integration of all the masses, 

 must suffice again to reduce it to the same nebulous form. 



Here, indeed, we arrive at a barrier to our reasonings; 

 since we cannot know whether this condition is or is not 

 fulfilled. If the ether which fills the interspaces of our 

 Sidereal System has a limit somewhere beyond the outer- 

 most stars, then it is inferrable that motion is not lost by 

 radiation beyond this limit; and if so, the original degree 

 of diffusion may be resumed. Or supposing the ethereal 

 medium to have no such limit, yet, on the hypothesis of an 

 unlimited space, containing, at certain intervals, Sidereal 

 Systems like our own, it may be that the quantity of molecu- 

 lar motions radiated into the region occupied by our Sidereal 

 System, is equal to that which our Sidereal System radiates ; 

 in which case the quantity of motion possessed by it, re- 

 maining undiminished, it may continue during unlimited 

 time its alternate concentrations and diffusions. But if,* 

 on the other hand, throughout boundless space filled with 

 ether, there exist no other Sidereal Systems subject to like 

 changes, or if such other Sidereal Systems exist at more 

 than a certain average distance from one another; then it 



