200 COSMICAL ARRANGEMENTS. 



the same Providence which formed the system, 

 should permit it to continue so long) when this 

 cause will entirely change the length of our year 

 and the course of our seasons, and finally stop 

 the earth's motion round the sun altogether. 

 The smallness of the resistance, however small 

 we choose to suppose it, does not allow us to 

 escape this certainty. There is a resisting me- 

 dium ; and, therefore, the movements of the solar 

 system cannot go on for ever. The moment such 

 a fluid is ascertained to exist, the eternity of the 

 movements of the planets becomes as impossible 

 as a perpetual motion on the earth. 



3. The vast periods which are brought under 

 our consideration in tracing the effects of the 

 resisting medium, harmonize with all that we 

 learn of the constitution of the universe from 

 other sources. Millions, and millions of millions 

 of years are expressions that at first sight appear 

 fitted only to overwhelm and confound all our 

 powers of thought : and such numbers are no 

 doubt beyond the limits of any thing which we 

 can distinctly conceive. But our powers of con- 

 ception are suited rather to the wants and uses 

 of common life, than to a complete survey of the 

 universe. It is in no way unlikely that the 

 whole duration of the solar system should be a 

 period immeasurably great in our eyes, though 

 demonstrably finite. Such enormous numbers 

 have been brought under our notice by all the 



