yo CORRELATION OF PHYSICAL FORCES. 



to the beginning or end of worlds, are contemplated from a 

 physical point of view, the period of time over which our 

 experience, in its most enlarged sense, extends, is so inde- 

 finitely minute with reference to that which must be 'required 

 for any notable change, even in our own planet, that a variety 

 of theories may be framed equally incapable of proof or of 

 disproof. We have no means of ascertaining whether many 

 changes, which endure in the same direction for a term 

 beyond the range of human experience, are really continuous 

 or only secular variations, which may be compensated for at 

 periods far beyond our ken, so that in such cases the question 

 of comparative stability or change can at best be only 

 answered as to a term which, though enormous with reference 

 to our computations, sinks into nothing with reference to 

 cosmical time, if cosmical time be not eternity. Subjects 

 such as these, though of a kind on which the mind delights 

 to speculate, appear, with reference to any hope of attaining 

 reliable knowledge, far beyond the reach of any present or 

 immediately prospective capacity of man. 



