164 CHEMISTRY. 



and there stands at the porch of nature no snarl- 

 ing Cerberus, with his three heads, all wrong ones, 

 and his " confusion of tongues. 



How this singular action of matter in the state 

 of air is carried on in all cases, so as to produce 

 the endless variety that we see in nature, we can- 

 not of course know ; but we do know the results 

 of it in many instances, and that knowledge is, 

 the foundation of nine-tenths of those arts by the 

 practice of which we get our food, our clothing, 

 and all our accommodations and comforts. Men 

 have " groped their way" to some portion of that 

 knowledge; but it is only since -the introduction of 

 modern or pneumatic chemistry, that is, the science 

 of " the secrets of airs" that it has been followed 

 as a regular science : and when we think of gas- 

 lights, and steam-boats, and ten thousand other 

 things that we possess in consequence of it, we 

 cannot be too grateful to those who made and 

 applied the- -discoveries to which we owe these. 

 And we have this to encourage us in the matter, 

 that the whole is the result of observation of that 

 observation of nature which is far more open to 

 us than it was to those men, for they have left us 

 their keys. 



But if the aerial state of things be, as it cer- 

 tainly is, the real and only state in which nature 

 acts, then the atmosphere must necessarily be the 

 general theatre of nature's acting. Nor is there 

 any doubt that it is. There are, indeed, some 

 operations which could not be carried on in the 

 atmosphere, because some of the materials would 

 be dissipated by that; and there are others in 

 which all the materials would go off together. 

 Thus we can get the water out of brine, and leave 



