208 



ON THE AIR AND BAIN OF MANCHE8TEB. 



thinking are too indefinite to be considered as opinions, and 

 they belong also to that state of mind so common to early 

 ages, and not uncommon in our own times, which confounds 

 the idea of substance and elements with the ideas of power 

 and character. These words may certainly be made to bear a 

 closely approaching signification when viewed from a meta- 

 physical point of view, but in physical science their limits are 

 distinct. 



The air has been a fertile source of inquiry and speculation 

 in all times ; the early writers seem lost in the vastness and 

 vagueness of the subject, and the history of opinion upon it, 

 up almost to the present century, is like the history of some 

 non-physical or metaphysical subject. It is a common notion 

 that our mental part must resemble air, and we might readily 

 make an interesting history of the indefinite ideas and con- 

 fused reasoning which introduced into our language such ex- 

 pressions as " the spirit of wine" and "pneumatic chemistry." 

 But here, as in many other cases, whilst the true solution has 

 been difficult and late, the main points have been seized very 

 early, and whilst we may fairly object to, or smile at the 

 use of phrases which shew our opinions to be taken from 

 those who thought, like Anaximenes, that the soul was 

 aerial, we scarcely diflfer from him when we say, as we may 

 fairly do, " that plants and animals are made of air and return 

 to air." 



We cannot say much for the increase of clearness of 

 thought when we compare this with a description of air 

 written (per Johnsonum Chymicum) in 1552. " Aer est spi- 

 ritus, spiritus est ventus," " The air is spirit, spirit is wind." 

 Nor even coming later, to the time of Stahl, who lived at the 

 beginning of the last century, and who had followers, great 

 men, also in this century, do we see it much improved. Stahl 

 says, — "Air is nothing but aether mixed with aqueous efiluvia 

 and the exhalations of solid bodies." Also he calls it in better 

 style, " a light dry body, mixed with various particles of saline, 



