CHAPTER XIII. 



MISCELLANEOUS EXAMPLES OF THE EXPLANATION OF 

 LAWS OF NATURE. 



1. THE most striking example which the history of 

 science presents, of the explanation of laws of causation and 

 other uniformities of sequence among special phenomena, by 

 resolving them into laws of greater simplicity and generality, 

 is the great Newtonian generalization : respecting which 

 typical instance so much having already been said, it is 

 sufficient to call attention to the great number and variety of 

 the special observed uniformities which are in this case 

 accounted for, either as particular cases or as consequences of 

 one very simple law of universal nature. The simple fact of 

 a tendency of every particle of matter towards every other 

 particle, varying inversely as the square of the distance, 

 explains the fall of bodies to the earth, the revolutions of the 

 planets and satellites, the motions (so far as known) of comets, 

 and all the various regularities which have been observed in 

 these special phenomena; such as the elliptical orbits, and 

 the variations from exact ellipses ; the relation between the 

 solar distances of the planets and the duration of their 

 revolutions ; the precession of the equinoxes ; the tides, and a 

 vast number of minor astronomical truths. 



Mention has also been made in the preceding chapter of 

 the explanation of the phenomena of magnetism from laws of 

 electricity ; the special laws of magnetic agency having been 

 affiliated by deduction to observed laws of electric action, in 

 which they have ever since been considered to be included as 

 special cases. An example not so complete in itself, but even 

 more fertile in consequences, having been the starting point 

 of the really scientific study of physiology, is the affiliation, 

 VOL. i. 34 



