358 NATURAL THEOLOGY. 



nothing can be more surprising than their evolu- 

 tions, like figures in a dance, apparently produced 

 by the attraction and repulsion of the particles 

 themselves. It might be supposed that the rapid 

 evaporation from the surface of the drop would 

 produce eddies vrithin it, and that these molecules 

 were carried by the circulation of the fluid ; but 

 the ingenious mode by which Mr. Brown pre- 

 vented the evaporation of the watery particle, by 

 surrounding it with oil, whilst the motions of the 

 molecules continued, refutes this hypothesis, and 

 inclines us the more to rejoice that the curious 

 phenomenon was discovered, not accidentally, but 



by a philosopher. 



Indeed, wnusi looking upon iiiesc mulccuies, 

 we are surprised by bodies, obviously animalcules, 

 jostling them, and darting across the field of the 

 microscope ; and the natural reflection is, how 

 much more minute must the constituent parts, or 

 molecules, of these animalcules be ! Their motions 

 are not fortuitous, or owing to any polarization or 

 influence external to them, as galvanism or mag- 

 netism : they have instincts and appetites, and 

 are susceptible of excitement : their bodies are 

 nourished by digestion, or imbibition : they have 

 circulation, though it may be with a different 

 apparatus from that of larger animals : their cir- 

 culating fluids, their containing vessels, their ap- 

 paratus for motion, imply that the ultimate mole- 

 cules of their composition must be infinitely small, 

 even in comparison with the minute particles 



