NATURAL THEOLOGY. 27 



for ever wheel round the earth instead of falling 

 down upon it. This is the principle which sus- 

 tains the heavenly motions. The Deity having 

 appointed this law to matter, (than which, as we 

 have said before, no law could be more simple,) 

 has turned it to a wonderful account in construct- 

 ing planetary systems. 



The actuating cause in these systems is an at- 

 traction which varies reciprocally as the square of 

 the distance ; that is, at double the distance, has a 

 quarter of the force ; at half the distance, four 

 times the strength ; and so on. Now concerning 

 this law of variation, we have three things to ob- 

 serve ; first, that attraction, for any thing we know 

 about it, was just as capable of one law of varia- 

 tion as of another ; secondly, that, out of an infi- 

 nite number of possible laws, those which were 

 admissible for the purpose of supporting the hea- 

 venly motions lay within certain narrow limits : 

 thirdly, that of the admissible laws, or those which 

 come within the limits prescribed, the law that 

 actually prevails is the most beneficial. So far as 

 these propositions can be made out, we may be 

 said, I think, to prove choice, and regulation : 

 choice, out of boundless variety ; and regulation, 

 of that which, by its own nature, was, in respect 

 of the property regulated, indifferent and indefinite. 



I. First, then, attraction, for any thing we know 

 about it, was originally indiflferent to all laws of 

 variation depending upon change of distance, i. e. 

 just as susceptible of one law as of another. It 



