'$19.] und a neio Galvanic Instrument. 179 



nescent ignition, was too minute to allow him to make the 

 observations which I had in view. 



Twenty copper and twenty zinc plates, about 19 inches 

 square, were supported vertically in a frame, the different metals 

 alternating a t one half mch distance from each other. Alt the 

 plates of the same kind of metal were soldered to a common 

 slip, so that each set of homogeneous plates formed one conti- 

 nuous metallic superficies. When the copper and zinc surfaces 

 thus formed are united by an intervening wire, and the whole 

 immerged in an acid, or aceto-sahne solution, in a vessel devoid 

 of partitions, the wire becomes intensely ignited ; and when 

 hydrogen is liberated, it usually takes fire, producing a very 

 beautiful undulating or corruscating flame. 



1 am confident, that if Voita and the other investigators of 

 galvanism, instead of multiplying the pairs of galvanic plates, 

 had sought to increase the effect by enlarging one pair as I have 

 done (tor 1 consider the copper and zinc surfaces as reduced to 

 two by the connexion), the apparatus would have been considered 

 as presenting a new mode of evolving heat as a primary effect 

 independently of electrical influence. There is no other indica- 

 tion of electricity when wires from the two surfaces touch the 

 tongue than a slight taste, such as is excited by small pieces of 

 zinc and silver laid on it and under it, and brought into contact 

 with each other. 



It vyas with a- view of examining the effects of the proximity 

 and alternation m the heterogeneous plates that I had them cut 

 into separate squares. By having them thus divided, I have 

 been enabled to ascertain that when all of one kind of metal are 

 ranged on one side of the frame, and all of the other kind on the 

 other side of it the effect is no greater than might be expected 

 from one pair of plates. 



Volta considering the changes consequent to his contrivance 

 as the effect of a movement in the electric fluid, called the pro- 

 cess electro-motion, and the plates producing it electro-motors. 

 But the phenomena show that the plates, as I have arranged 

 them, are calon-motors, or heat movers, and the effect caiori- 

 motion. lhat this is a new view of the subject, may be inferred 

 iroin the following passage in Davy's Elements. That great 

 chemist observes, " When very small conducting surfaces are 

 used tor conveying very large quantities of electricity, they 

 become ignited ; and of the different conductors that have been 

 compared, charcoal is must easily heated by electrical 

 discharges,* next iron, platina, gold, then copper, and lastly 

 zinc. J he phenomena of electrical ignition, whether takin' 

 place in gaseous, fluid, or solid bodies, always seem to be the 

 resu t of a violent exertion of the electrical, attractive, and 

 repellent powers, which may be connected with motions of the 



T luJ : app O arai J ui! ,nSa,edraWn froraex P eri " u ' n(s '»ade by ll.e electrici.y of the 



vi V 



