33 



the ocean within its hounds. Though the waves thereof 

 roar and swell, yet, checked by this curb, they are un- 

 able to pass even the slightest barrier of sand. To this 

 the mountains owe -that unshaken fimiiuss which laughs 

 at the shock of careering winds. By virtue of this invi- 

 sible mechanism, without any instrument of human de- 

 vice, thousands of tons of water are raised every mo- 

 ment into the regions of the firmament. By this they 

 continue suspended in the " air without any cistern to 

 contain them. By the same variously-acting power 

 they in due time dropdown again in gentle falls of dr.iv, 

 or are precipitated in copious showers of rain: they 

 slide down in fleecy flights of snow, or dart in clattering 

 showers of hail : this occasions the strong cohesion of 

 solid bodies, without which our large machines would 

 be utterly useless, and the nicer utensils of life elude our 

 expectations of service. In short, this is the laliast 

 which composes the equilibrium, and constitutes the 

 stability of things : this the great chain which forms 

 the connexion of universal nature, and the mighty. 

 engine, which in good measure accomplishes almost all 

 her operations. What complicated effects from a single 

 cause ! What profusion amidst frugality P 



How extremely plausible is ail this ! And what pity 

 that it is only plausible ! but it is really no more : it is 

 not capable of any substantial proof ; I mean, with re- 

 gard to the motion of the heavenly bodies, and the 

 causes of that motion. 



I do not know that any one has yet given a rational 

 answer to Dr. Rogers' observations on that head. " The 

 action of these two powers (gravitation and projection) 

 is inadequate to such a motion ; because, in order to 

 produce it, the gravitating force must exactly balance 

 the projectile : but where this done, one would destroy 

 the other: this will appear. plain if \ve consider the na- 

 ture of these two forces. Gravitation, by which the 

 earth attracts all bodies, is at all times uniformly ex- 

 erted in right lines, from the earth to the body attracted, 

 C 4 



