Source of Motions upon the Earth. 305 



and active, although the chemical force itself is probably lessened in 

 power in the same degree in which the molecules of matter are se- 

 parated from each other, or even perhaps in a greater degree. 



We accordingly find, that, in different regions, motions take place 

 to different amounts, in different modes, and with various energies ; 

 and that they possess organised bodies either peculiar to themselves, 

 or with variations and adaptations of their natures to the condition of 

 the forces proper to the several regions. In the frigid and temperate 

 parts of the earth, we have life existing in comparatively iew indivi- 

 dual beings, and its operations tai'dy and sluggish. Within the 

 tropics, again, we have vital forces acting with extreme activity, so 

 that more organisable matter seems to come within their influence, 

 and to be kept in action ; and we have life present in a great number 

 of individual beings, different in structure and in nature from those 

 of the other regions. But, although in different parts of the earth 

 the individual forces may vary in intensity, and act in different pro- 

 portions to each other, it must be held to be improbable that the two 

 classes of force ever vary in their proportion to each other, to any 

 great extent, or for any length of time. For any such variation 

 would be attended with most destructive consequences, as we have 

 endeavoured to shew. If any one force varies — if it is increased for 

 instance — and so tends to exalt the power of one of the classes over 

 the other, it must either be compensated by a depression of one or 

 more of the other forces belonging to the same class, or else there 

 must be a corresponding and equivalent exaltation of one or more of 

 the forces belonging to the opposite class, so as to preserve the ba- 

 lance between the two. For the absolute energy of both the classes 

 may be conceived to be increased or dinunished without any material 

 derangement of nature, if, in their increase or decrease, they pre- 

 serve the same proportion between themselves. And, again, the ab- 

 solute energies of the several forces belonging to each class may dif- 

 fer to some extent, if the general power of the whole of the forces 

 belonging to each class is proportional. Thus, if at any place 

 the forces of gravity and cohesion are lessened, and the solar and 

 vital forces be conceived to remain at the usual standard, it will be 

 necessary, for the continuance of the existing order of nature, that 

 the chemical forces be rendered more powerful, or more active, in 

 the degree in which the other forces of the same class are impaired. 

 For a greater activity of chemical force will compensate for a less 

 activity of the other physical forces, and vice versa. In the same 

 way a greater activity of vital force, in the case of plants, may be 

 compensated by a less activity of solar foi'ce, or vice versa. 



We have thus set before us, upon a small scale in the earth, the 

 results of the actions of various proportions of the forces productive 

 of motion and of organisation ; and only by a study and knowledge 

 of these — by discovering their exact effects in producing and varying 



