concerned in the Phenomena of ordinary Electricity, fyc. 205 



property of the wire, not of the current ; the ignition remains 

 momentarily because it was once excited; but the original igni- 

 tion is the phenomenon to be explained. So also with attrac- 

 tion and repulsion. 



If a temperature of 100° could be transmitted through a bar 

 of iron in an equable flow, the bar would no more rise beyond 

 100° than the temperature of a metallic tube would exceed 212°, 

 because boiling water had been long passed through it. So 

 electricity passing in a feeble, although abundant current, any 

 one portion of which is incapable of even affecting an electro- 

 meter, cannot by its total quantity passing in successive portions, 

 however rapidly, effect anything unless by accumulation ; and 

 then intensity must proportionally increase. But high intensity 

 is excluded by the hypothesis, and denied to exist in the case of 

 one pair of plates ; yet one large pair will exercise powers of 

 ignition which no other means in nature arc capable of. 



If the effective current from a single pair of large plates be 

 electricity, we might naturally expect it, whether in large or 

 small quantity, to evince its usual attributes of attraction and 

 repulsion. The circumstance of its being in large quantity, or 

 in rapid flow, should not deprive it of properties which are cha- 

 racteristic, as we have reason to believe inseparable, and the 

 absence of which has been always admitted as a proof of the 

 absence of the fluid itself. Why, then, is not that absence of 

 properties in certain voltaic phenomena admitted equally as a 

 proof that electricity is not in operation ? We should expect that 

 great quantity in rapid flow would rather promote than destroy 

 these peculiar effects. 



I think all the preceding considerations tend to show that the 

 agency of a large quantity of common electricity, at a low inten- 

 sity, fails to explain voltaic phenomena; or to account for the 

 absence of the properties of common electricity, while these 

 alleged large quantities of it are in the act of producing voltaic 

 phenomena; or to assign a reason for the presence, in a high 

 degree, of properties developed during voltaic phenomena, which 

 belong to common electricity only in a small degree. In fine, I 

 (•in i rind no evidence to prove that the alleged large quantity 

 of common electricity is at all present, since the most feeble de- 

 monstrations of it only are discoverable. But more of this here- 

 after. 



Quantity, considered as a cause, seems therefore to be of no 

 avail ; intensity appears to be the only intelligible source of 

 activity. I do not think there is one known phenomenon the 

 explanation of which receives any real assistance from the assumed 

 agency of quantity. M. Biot, probably observing this defect in 

 its supposed operation, has substituted the influence of velocity. 



