?.56 NATURAL THEOLOGY. 



v/hich result from the projectile impulse. By calculations 

 drawn from ancient notices of eclipses of the moon, we can 

 prove that, if such a fluid exist at all, its resistance has 

 had no sensible effect upon the moon's motion for two thou- 

 sand five hundred years. The truth is, that except this one 

 circumstance of the variation of the attracting force at differ- 

 ent distances agreeing with the variation of the spissitude, 

 there is no reason whatever to support the hypothesis of an 

 emanation ; and there are, as it seems to me, almost insu 

 perable reasons against it. 



(*) II. Our second proposition is, that while the possi 

 ble laws of variation were infinite, the admissible laws, oi 

 the laws compatible with the preservation of the system, lie 

 within narrow limits. If the attracting force had varied 

 according to any direct law of the distance, let it have been 

 what it would, great destruction and confusion would havB 

 taken place. The direct simple proportion of the distance 

 would, it is true, have produced an ellipse ; but the per- 

 turbing forces would have acted with so much advantage 

 as to be continually changing the dimensions of the elhpse 

 in a manner inconsistent with our terrestrial creation. For 

 Instance, if the planet Saturn, so large and so remote, had 

 attracted the earth, both in proportion to the quantity of 

 matter contained in it, which it does, and also in any pro- 

 portion to its distance, that is, if it had pulled the harder 

 for being the further off, instead of the reverse of it, it would 

 have dragged out of its course the globe which we inhabit, 

 and have perplexed its motions to a degree incompatible 

 with our security, our enjoyments, and probably our exist- 

 ence. Of the inverse laws, if the centripetal force had 

 changed as the cube of the distance, or in any higher pro- 

 portion ; that is — for I speak to the unlearned — if, at double 

 the distance, the attractive force had been diminished to an 

 eighth part, or to less than that, the consequence would have 

 been, that the planets, if they once began to approach the 

 Eun, would have fallen into his body ; if they oviv.o. thoiigh 



