10? 



cates to air and water, when reduced into vapours, that 

 prodigious force which renders them capable of shaking 

 the earth, and breaking the hardest bodies. 



Lastly, it is fire, that by penetrating fluids, preserves 

 to them their fluidity. As it is exact itself, in putting 

 itself in equilibria, it passes from those bodies where it 

 is most abundant to those where it is least so, and car- 

 rying with it the most volatile particles, it deposits them 

 on the surface of the latter, whei'e they appear in the 

 form of vapours, exhalations or mists. 



7- The air, by its fluidity, thinness, weight, and spring, 

 is next to fire, the most powerful agent in nature. It is 

 one of the great principles of the vegetation of plants, 

 and of the circulation of liquors in all organized bodies, 

 It is the receptacle of the particles which exhale from, 

 different matters : and had we eyes sufficiently piercing, 

 we should see it in the abridgement of all the bodies 

 that exist on the surface of our globe. From vapours 

 and exhalations which it carries in its bosom, and dis- 

 perses into all parts, are produced aqueous and fiery 

 meteors, which are so useful, but sometimes dreadful. 



The air does not only receive bodies : it even enters 

 into their composition. When divested of its elasticity, 

 it unites itself to the particles which compose them, and 

 augments their bulk. But being more unalterable than 

 gold, it resumes its former nature when these bodies 

 change or are dissolved. Being disturbed in its equi- 

 librium, it swells the sails of our ships, and conveys to 

 our countries those. rich fleets that cause plenty. Be- 

 coming impetuous, it causes tempests and hurricanes : 

 but even this impetuosity is not without its use : the air, 

 by this means, divest itself of noxious vapours, and 

 the waters being strongly agitated, are preserved from a 

 fatal corruption. 



Lastly, the air is the vehicle of sounds and odours,,, 

 and under these new relations it is essentially allied to 

 two of our senses. The partial vibration which com* 

 motion excites in a sonorous body, communicates itself 



