40 NATURAL THEOLOGY. 



(*) V. What we have seen in the law of the 

 centripetal force, viz. a choice guided by views of 

 utility, and a choice of one law out of thousands 

 which might equally have taken place, we see no 

 less in the figures of the planetary orbits. It was 

 not enough to fix the law of the centripetal force, 

 though by the wisest choice ; for even under that 

 law, it was still competent to the planets to have 

 moved in paths possessing so great a degree of 

 eccentricity, as, in the course of every revolution, 

 to be brought very near to the sun, and carried 

 away to immense distances from him. The comets 

 actually move in orbits of this sort ; and, had the 

 planets done so, instead of going round in orbits 

 nearly circular, the change from one extremity of 

 temperature to another must, in ours at least, have 

 destroyed every animal and plant upon its surface. 

 Now the distance from the centre at which a planet 

 sets off, and the absolute force of attraction at 

 ^ that distance, being fixed, the figure of its orbit, 

 its being a circle, or nearer to, or further off from 



tions of the sun and planetary masses on each other. Why was 

 it not extended to these ? The simple answer is, that it would not 

 only have been useless, but it would have interfered with the 

 purposes for which these bodies were designed. Thus these 

 great bodies are moved by laws of the utmost simplicity, while 

 their component parts act on each other by a combination of 

 forces of various kinds; which forces appear to act at small dis- 

 tances only, while the forces on which depend the welfare and 

 preservation of our earth and the planets, act through a vast ex- 

 tent of space, and by one simple and uniform law, in which there 

 is no conflicting interference of other actions. 



