THEIR ARRANGEMENTS AND FORMATION. 7 



these marvels rest on mathematical calculations of the nicest 

 exactness, insomuch that, taking one as an example, astrono- 

 mers have computed ten years beforehand, the time at which 

 the planet Jupiter would pass our meridian, and the predicted 

 time was correct within half a second. 



Since Xewton stated the laws of gravity and of the pla- 

 netary motions, there have been some important additions to 

 his philosophy. It has been shown, that certain perturbations in 

 the planetary movements, which appeared to him as denoting 

 a necessary end to the system, observe periods, and are only 

 further proofs of the stability of the whole arrangement. It has 

 also been discovered that the laws of motion extend beyond 

 the solar system. Amongst the serene orbs, which seem so 

 still to our ordinary perceptions, we now know that there is 

 no such thing as rest. Stars are ascertained to have proper 

 motions, of the same nature with that found in our own sun. 

 Many are seen to be, in reality, double or triple that is, com- 

 posed of a plurality of suns, which perform regular revolution- 

 ary motions around each other in ellipses. The periods of 

 some of these movements and revolutions are of such brevity, 

 that their elements are already in the book of the astronomer ; 

 others are seen to be of such vastness, that the times which have 

 determinated the youth and death of our oldest empires, would 

 be, in the comparison, but as a little spoke in some enormous 

 wheel. Yet of all of them no doubt can be entertained that 

 they depend upon those simple physical laws which preside 

 over every particle of tangible matter in our own sphere. 



Here it is right to advert to some general features of the 

 solar system, most of which have also been discovered since 

 the days of Xewton. It is, in the first place, remarkable, 

 that the planets all move nearly in one plane, corresponding 

 with the centre of the sun's body. Xext, it is not less worthy 

 of attention, that the motion of the sun on its axis, those of 

 the planets around the sun, and the satellites around their 

 primaries, ( 4 ) and the motions of all on their axes, are in one 

 direction namely, from w r est to east. Had all these matters 

 been left to accident, the chances against the uniformity 

 would have been, though calculable, inconceivably great. 



