248 NATURAL THEOLOaY. 



glomes, etc., bear no affinity to them, in the cause and prin- 

 ciple by which their motions are actuated. I can assign fbi 

 this difference a reason of utihty, namely, a reason why,- 

 though the action of terrestrial bodies upon each other be, in 

 almost all cases, through the intervention of solid or fluid 

 substances, yet central attraction does not operate in this 

 manner. It was necessary that the intervals between the 

 planetary orbs should be devoid of any inert matter, either 

 fluid or solid, because such an intervening substance would, 

 by its resistance, destroy those very motions which attrac- 

 tion is employed to preserve. This may be a final cause o1 

 the difference ; but still the difference destroys the analogy. 



Our ignorance, moreover, of the sensitive natures by 

 which other planets are inhabited, necessarily keeps from us 

 the knowledge of numberless utilities, relations, and subser- 

 viences, which we perceive upon our own globe. 



After all, the real subject of admiration is, that we un- 

 derstand so much of astronomy as we do. That an animal 

 confined to the surface of one of the planets, bearing a less 

 proportion to it than the smallest microscopic insect does to 

 the plant it lives upon — that this little, busy, inquisitive 

 3reature, by the use of senses which were given to it for its 

 domestic necessities, and by means of the assistance of those 

 senses which it has had the art to procure, should have been 

 enabled to observe the whole system of worlds to which its 

 own belongs and the changes of place of the immense globes 

 which compose it, and with such accuracy as to mark out 

 beforehand the situation in the heavens in which they will 

 be found at any future point of time ; and that these bodies, 

 after sailing through regions of void and trackless space, 

 should arrive at the place where they were expected, not 

 within a minute, but within a few seconds of a minute, of 

 the time prefixed and predicted : all this is wonderful, 

 whether Vv'^e refer our admiration to the constancy of the 

 heavemy motions themselves, or to the perspicacity and pre- 

 cision wdth which they have been noticed by mankind. 



