134 THE PHILOSOPHY 



gledted during fleep, when confcioufnefs is often almoft totally fu- 

 fpended. But Nature in her operations is always wife. She has 

 given to man, and other animals, the direction of no movements 

 but what are eafily performed, contribute to pleafure and health, 

 and enable them to acquire food correfponding to the ftrudure of 

 their bodies and the elements in which they live. 



It never was my intention, and, indeed, it would have been fo- 

 reign to the defign of this work, and ill fuited to that clals of man- 

 kind to whom I wifh chiefly to be ufeful, to enter into the rationale 

 of animal motion ; to mention the number, Infertion, and diredion, 

 of the mufcles employed in moving the different parts of animated 

 bodies ; or to account for the modes by which animals walk, leap, 

 fly, fwim, creep, &c. Such difcuflions would not only require a 

 volume, but a thorough acquaintance with all the depths of anato- 

 mical and mathematical knowledge. "What follows, therefore, will 

 confift of fome defultory obfervations ; and the fubjedl fhall be con- 

 cluded by enumerating a few examples of movements peculiar to 

 certain animals. 



The motions of animals are proportioned to their weight and 

 ftrufture. A flea can leap fome hundred times its own length. 

 Were an elephant, a camel, or a liorfe, to leap in the fame propor- 

 tion, their weight would crufti them to atoms. The fame remark 

 is applicable to fpiders, worms, and other infefts. The foftnefs of 

 their texture, and the comparative fmallnefs of their fpecific gravi- 

 ty, enable them to fall vvfith impunity from heights that would 

 prove fatal to larger and heavier animals. 



Motion gives birth, perfedion, death, and reprodudion, to all 

 animal and vegetable beings. It is the caufe of all that diverfity 

 and change which perpetually affed every objedt in the univerfe. 



The 



