184 UNION OF AIR AND VAPOUR. 



the water has ascended the more minutely must it 

 be divided, and the farther must all the parts be from 

 each other. The action of the heat destroys the 

 cohesion of the water with the pool, or the leaf, or 

 other surface from which it rises, the very moment 

 that it begins to ascend ; and the cohesion of the 

 ascending parts becomes less and less, even much 

 faster than the diminishing size, because of the 

 distance that they are apart, and that is the reason 

 why vapour, which is so dense as not only to form 

 a light floating rack, but castled clouds, with edges 

 as well defined as if they were terrestrial solids, 

 and even an entire covering, that extends over the 

 whole visible heavens, and shadows the earth to very 

 deep gloom, while yet that these formations ride 

 buoyant on the air, and some of them are indications 

 of dry weather. 



Thus though the air is the passage of the ascend- 

 ing watef which is to maintain the springs, it is no 

 more the cause of the ascent than the channel of a 

 river is the cause why the tide of that river flows 

 downwards, and the vapour, whether it be invisible 

 or in clouds, is obeying the laws of its own nature, 

 and in nowise under the control of or attracted by 

 the air. Were there an attraction, and if the air 

 and the water actually united in their ultimate par- 

 ticles, and formed a new substance, as an acid and 

 an alkali do in the formation of a salt, we should 

 soon, from the vast extent of surface at which they 

 constantly meet each other (which may be said to 

 be, considering how many moist substances stand 

 surrounded by the air, and how often the face of the 

 water is wrinkled with waves, equal to that of the 

 whole globe) if they acted chymically upon each 

 other we should very soon have neither air nor 

 water; but a compound of the two: differing as 

 much in its properties from either as the neutral salt 

 does from the acid and the alkali. Common salt, 

 which renders our food so savoury and so whole- 



