THE LAWS OF MOTION. 237 



for the selection of this law of the preservation 

 of motion. If the case had been otherwise, the 

 universe must necessarily in the course of ages 

 have been reduced to a state of rest, or at least 

 to a state not sensibly differing from it. If the 

 earth's motion, round its axis, had slackened by 

 a very small quantity, for instance, by a hun- 

 dredth of a second in a revolution, and in this 

 proportion continued, the day would have been 

 already lengthened by six hours in the 6000 

 years which have elapsed since the history of the 

 world began ; and if we suppose a longer period 

 to precede or to follow, the day might be increased 

 to a month or to any length. All the adaptations 

 which depend on the length of the day would 

 consequently be deranged. But this would not 

 be all ; for the same law of motion is equally 

 requisite for the preservation of the annual motion 

 of the earth. If her motion were retarded by 

 the establishment of any other law instead of the 

 existing one, she would wheel nearer and nearer 

 to the sun at every revolution, and at last reach 

 the centre, like a falling hoop. The same would 

 happen to the other planets ; and the whole solar 

 system would, in the course of a certain period, 

 be gathered into a heap of matter without life or 

 motion. In the present state of things on the 

 other hand, the system, as we have already ex- 

 plained, is, by a combination of remarkable 

 provisions, calculated for an almost indefinite ex- 

 istence, of undiminished fitness for its purposes. 



