DISSOLUTION. 543 



molecular motion pervading space. Thus the questions we 

 have to consider, are — Whether after the completion of all 

 the relative equilibrations which bring Evolution to a close, 

 there remain any further equilibrations to be effected? — 

 Whether there are any other motions of masses that must 

 eventually be transformed into molecular motion? — And if 

 there are such other motions, what must be the consequence 

 when the molecular motion generated by their transforma- 

 tion, is added to that which already exists? 



To the first of these questions the answer is, that there do 

 remain motions which are undiminished by all the relative 

 equilibrations we have considered; namely, the motions of 

 translation possessed by those vast masses of matter called 

 stars — remote suns that are probably, like our own, sur- 

 rounded by circling groups of planets. The belief that the 

 stars are fixed, has long since been abandoned: observation 

 has proved many of them to have sensible proper motions. 

 Moreover, it has been ascertained by measurement that in 

 relation to the stars nearest to us, our own star travels at 

 the rate of about half a million miles per day; and if, as is 

 admitted to be not improbable, our own star is moving in 

 the same direction with adjacent stars, its absolute velocity 

 may be, and most likely is, immensely greater than this. 

 Now no such changes as those taking place within the Solar 

 System, even when carried to the extent of integrating the 

 whole of its matter into one mass, and diffusing all its 

 relative motions in an insensible form through space, can 

 affect these sidereal motions. Hence, there appears no alter- 

 native but to infer that they must remain to be equilibrated 

 by some subsequent process. 



The next question that arises is — To what law do sidereal 

 motions conform? And to this question Astronomy replies 

 — the law of gravitation. The movements of binary stars 

 have proved this. The periodic times of sundry binary stars 

 have been calculated on the assumption that their revolu- 

 tions are determined by a force like that which regulates the 



