Production of electricity by friction. qq^ 



pie of rational theory, to receive it as a general and welt 

 established law in electrical science* I have already endea- 

 voured to show, that the decomposition of bodies by galvan- 

 ism depends on the operation of this lav/; and that the operates in gal- 

 commonly received opinions, respecting the excitement oP^"'^.'^^«^o'"- 

 tbe galvanic battery, are entirely inconsistent with it. The ' 



object of the following pages is to prove, that the excitement and is the 

 of bodies by friction is referrible to the same general law, ment bv^^"* 

 and is the effect of the contiict and separation of dissimilar friction. 

 bodies. 



In what manner the contact and separation of dissimilar How it causes 

 bodies operate as a cause of electrical excitement, I do not ^'."^^ explain. 

 pretend to explain ; nor am I, at present, anxious to deter- 

 mine, how much of the effect is to be attributed to the con- 

 tact, how much to the separation : it is sufficient, for the 

 purpose of my argument, to repeat, that no excitement is 

 visible as long as the bodies are in contact,- and that, imme- 

 diately as they are separated, they indicate opposite electri- 

 citiesi 



:■ It must be obvious, that, while we are drawing one body Contact and 

 over another, a number of points in the surface of the rub- separation 

 , ^ , 1 • -1 T ''^^ necessary 



ber are first brought into contact with a correspondmg set of effects of rub* 



points in the surface of the body rubbed ; that they are then ^'^'^K* 

 separated from them^ and brought into contact with another 

 setof points, and so on, until the one body has passed entirely 

 over the other. Now, at each separation, if the bodies be of 

 different kinds, whether conductors or nonconductors, the 

 general law, we have stated, must operate, and opposite 

 electrical states must be excited in the separated particles. 

 So far, therefore, the excitement by friction, and the excite- 

 ment by contact and separation, appear to be referrible, in a 

 general manner, to the same principle. We shall now pro- 



iceed to a more particular consideration of the subject. 



The principal facts, relative to the excitement of bodies principal facts 

 bv friction, may be expressed in the five followinon proposi- ""^'^^'^^ ^^ ex. 

 . „ J . 7 /. • .- • • . „ citementby 



.tions. 1. To produce excitanent by jriitum, it is essentinUy if^^^xion. 



necessary, that one or both the bodies employed in the opera- 

 tion be of the class of electrics, 2. // two electrics^ or an 

 electric and an insulated conductor be employed, the one body 

 ,Moilli after the operation, indicate an electricity opposite to 

 / Vol. XXXI»— April, 181 ^. X that 



