256 ON THE ELECTRIC COLUMN. 



** raento : neque minus inter se difFerunt, quam denstt Sc 

 *• tangibiles pa'rtes, ornnibusque tavgibUibus corporibus in- 

 *' sunt plus minusve, & plerumque nunquam ccfesant. Ab 

 •*' his, eoruraque motibus, prwcipue procedunt arefactio, 

 *' colliquatio, coucoctio, maturatio, putiefactio, vivificatio, 

 *' h praecipua naturce efFecta*." 

 Occult causes. Not to admit the existence of such substances, because 

 they escape our sight or touchy would be returning back to 

 occult properties, essential qualities, which, in the infancy 

 ^ of natural philosophy gratified the imagination under the 



shape of cmises. However, these conceptions were a be- 

 ginning of knowledge, as under that form were gathered a 

 certain number of important phenomena, successively ob- 

 served ; but of these the agents were still to be sought for. 

 Imponderable However it has been only at the birth o{ pneumatic physics, 

 substances, ^pj when its progress has occasioned the investigation oF 

 the chemical affinities of light and Jire, that many mysteries 

 in nature have been unfolded; and what a field of new re- 

 , searches has been opened by the attention given to a third 



imponderable substance, the electric Jiuid ! Now, these very 

 great steps teach us, that no progress, marked by such me- 

 morable epochs, and followed by so many important con- 

 sequences, can be expected but by farther discoveries in 

 still to be dis- the same class of substan^-es, some of which may happen to 

 covered, manifest themselves also by characteristic effects, either- 



known but mistaken, or yet unnoticed, and in these cases 

 they might in some degree be submitted to analysis, by the 

 changes they operate i-n certain phenomena, already known, 

 but not sufficiently determined. 



* " Human knowledge ha? hitherto been guided by viewing and behold- 

 irg; so that whatever escapes our eyes, either from the SKiallness of the 

 body itself, the tenuity of its particles, or the subtility of its motions, is 

 but little explored. By these however nature is chiefly governed; and 

 if they be neglected, a ju^t analysis cannot be made, or the processes of 

 nature disclosed. The expansible fluids, that exist in all tangible sub- 

 stances, are scarcely known. Tliese fluids are nothing but natural bo- 

 ' dies, proportionally rarefied, included in the parts of tangible substances 



as in a case : nor do they differ less from each other, than the dense and 

 tangible parts, they inhere more or less in all tangible bodies, and for the 

 most part are never still. To these, and their motions, are owing in 

 particular rarefaction, dissolution, concoction, maturation, putrefaction, 

 vivification, and the principal effects of juitiu-e." ' C. 



