6 FINAL CAUSES. 



In the investigation of the powers which are con- 

 cerned in the phenomena of living beings we meet 

 with difficnlties incomparably greater than those 

 that attend the discovery of the physical forces 

 which actuate the parts of inanimate matter. The 

 elements of the inorganic world are few and simple ; 

 the combinations they present are, in most cases, 

 easily unravelled ; and the powers which effect 

 their union, their changes, and their motions, are 

 reducible to a small number of general laws, of 

 which the results may, for the most part, be an- 

 ticipated and exactly determined by calculation. 

 What law, for instance, can be more simple than 

 that of gravitation, to which all material bodies, 

 whatever be their size, figure, or other properties, 

 and whatever be their relative positions, are equally 

 subjected ; and of which the observations of modern 

 astronomers have rendered it probable that the 

 influence extends to the remotest regions of space? 

 The most undeviating regularity is exhibited in the 

 motions of those stupendous planetary masses, 

 which continually roll onwards in the orbits pre- 

 scribed by this all -pervading force. Even the 

 slighter perturbations occasioned by their mutual 

 influence are but direct results of the same general 

 law ; and are necessarily restrained within certain 

 limits, which they never can exceed, and by which 

 the permanence of the system is effectually secured. 

 All the terrestrial changes dependent on these 

 motions partake of the same constancy. The same 

 periodic order governs the succession of day and 

 night, the rise and fall of the tides, and the return 

 of the seasons : which order, as far as we can per- 

 ceive, is incapable of being disturbed by any exist- 

 ing cause. 



