108 TERRESTRIAL ADAPTATIONS. 



water, of steam, of air, the effects of the earth's 

 annual and diurnal motions, and probably other 

 causes, so adjusted, that through all their struggles 

 the elemental world goes on, upon the whole, so 

 quietly and steadily ? Why is the whole fabric 

 of the weather never utterly deranged, its balance 

 lost irrecoverably ? Why is there not an eternal 

 conflict, such as the poets imagine to take place 

 in their chaos ? 



" For Hot, Cold, Moist, and Dry, four champions fierce, 

 Strive here for mastery, and to battle bring 

 Their embryon atoms : 



to whom these most adhere 

 He rules a moment : Chaos umpire sits, 

 And by decision more embroils the fray."* 



A state of things something like that which 

 Milton here seems to have imagined, is, so far as 

 we know, not mechanically impossible. It might, 

 have continued to obtain, if Hot and Cold, and 

 Moist and Dry had not been compelled to " run 

 into their places." It will be hereafter seen, 

 that in the comparatively simple problem of 

 the solar system, a number of very peculiar 

 adjustments were requisite, in order that the 

 system might retain a permanent form, in order 

 that its motions might have their cycles, its 

 perturbations their limits and period. The prob- 

 lem of the combination of such laws and materials 



* Par. Lost, b. 11. 



