FINAL CAUSES. 21 



two centuries, been carried to a height of perfection which 

 affords just grounds for exultation in the achievements of the 

 human intellect. 



In the investigation of the powers which are concerned in 

 the phenomena of living beings, we meet with diflficulties in- 

 comparably greater than those that attend the discovery of 

 the physical forces by which the parts of inanimate matter 

 are actuated. The elements of the inorganic world are few 

 and simple; the combinations they present are in most cases 

 easily unravelled; and the powers which actuate their mo- 

 tions, or effect their union and their changes, are reducible 

 to a small number of general laws, of which the results may, 

 for the most part, be anticipated, and exactly determined by 

 calculation. What law, for instance, can be more simple 

 than that of gravitation, to which all material bodies, what- 

 ever 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 prescribed 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 per- 

 manence of the system is effectually secured. All the ter- 

 restrial changes dependent on these motions partake of the 

 same constancy. The same periodic order governs the suc- 

 cession 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 existing cause. 



Equally definite are the operations of the forces of cohe- 

 sion, of elasticity, or of whatever other mechanical powers 

 of attraction or repulsion there may be, which actuate, at in- 

 sensible distances, the particles of matter. We see liquids, 

 in obedience to these forces, collecting in spheroidal masses, 



