304 Dr Robert E. Brown on the 



result and the equivalent of that manual force. Finally, we endea- 

 voured to shew that vital force is, in some degree, secondary to solar 

 force, and that all vital action is dependent upon the sun, and upon 

 circumstances produced by its agency, as well as by that of other 

 matter external to the earth. If the earth were left to itself, and to 

 its inherent forces, these would soon equilibrate themselves, and all 

 motion would cease. The forces of external nature destroy the equili- 

 brium of the terrestrial forces ; and it would therefore appear, that, 

 in external nature, and chiefly in the sun, are originated all ter- 

 restrial motions, and that under their influence all of them are sus- 

 tained. 



From these remai-ks it will result, that, for the maintenance of the 

 existing order of things, and for the production of those sorts of or- 

 ganised beings which belong to this globe, the two classes of motions 

 must be adjusted to each other in a certain proportion, and preserve 

 an exact balance between themselves. If chemical affinity and the 

 other physical forces were greater than they are, the operations of 

 life, and of external nature upon matter, would be impeded or ar- 

 rested, unless they also were intensified in a like degree ; for a greater 

 force would be necessary to overcome the chemical and physical 

 forces. If the vital and solar forces, again, were augmented out of 

 proportion to the others, other forms of derangement and confusion 

 would result, tending to their own destruction as active forces, or as 

 forces acting as they do in the existing order of nature. For the 

 number of living existences being supposed to remain the same, the 

 greater extent of their operations, and the increased quantity of mat- 

 ter which they would require, could not be compensated by the che- 

 mical forces, and vital operations would necessarily either cease, or 

 take place only at intervals ; the intervals being occupied with the 

 destruction of organic matter, and the return of its materials back to 

 an inorganic state. 



In different regions of the earth, thei'e are considerable differences 

 in the degree of energy of the individual forces, and in the propor- 

 tion in which these exist, or act in relation to each other. In the 

 torrid zone, as compared with the frigid and the temperate zones, 

 the force of gravity is diminished, consequent upon the increase of 

 the centrifugal tendency ; the solar influence, on the other hand, is 

 increased to a great degree, and as a result of this, we have cohesion 

 more strongly opposed, and, therefore, more easily overcome, by other 

 agents. With regard to the vital and chemical forces, whether they 

 are increased in real amount, or how far they are intrinsically af- 

 fected, is uncertain. But the condition of the other forces, by 

 rendering the jnolecules of matter more mobile, will cause them to 

 act with more ease, and with greater activity ; just as we know that 

 heat, by increasing the mobility of the molecules of matter, gives a 

 facility to chemical action, and renders molecular changes more easy 



