ON THE THEORY OF GALVANISM. 71 



means this difference of intenfity is produced. By different 

 degrees of electrical intenfity it is generally underitood, that 

 the fame quantity of uncombined * electric matter may be dif- 

 fufed through a greater or left fpace, and in confequence of 

 this, as it exifts in a irate of concentration or dilution, it will 

 exhibit effects more or lefs violent. In the galvanic pile it 

 might have been fuppofed from the fmall bulk of the apparatus, 

 that a large quantity of electric matter could not have exifted 

 in it except in a concentrated ftate, but we find that the con- 

 trary is invariably the cafe ; nor has any method been hitherto 

 contrived by which the electricity of the pile can be made to 

 exhibit the fame marks of intenfity with that of the common 

 machine. Future experiments will probably enable us to de-but the nature 

 termine with more precifion in what the difference between a of the differences 



l irt-n-i of intenfity have 



greater or lefs intenfity confiits; poilibiy the electric fluid, as no tbeen ex- 

 is the cafe with many other bodies, may differ in its nature plained. 

 according to the method employed for extricating it from the 

 fubftanees with which it w r as previoufly united. 



2. That the extrication of the electric fluid in the pile of The electricity 

 Volta depends upon the rapidity with which the furface of the of the P lle , de - 



i--ii/* i • i-i, , pends on the ra- 



metal is oxidated, after the experiments which have been pjaity of oxida- 



performed, and particularly thofe of Mr. Davy, feems to re- tion > &c * 



quire no farther proof. It is however not only neceffary that 



the fluid (hould be extricated, but that when difengaged it be 



concentrated and carried forward in a uniform direction. This 



confideration clearly explains the reafon why in the conftruc- 



tion of a pile there muff either be two metals employed, which 



are differently acted upon by the interpofed fluid, or that the 



different furfaces of the fame metal be fubjected to the aclion 



of different flnids. Dr. Van Marum conceives it impoffibleDr. VanMarum 



that the extrication of the ele&ric fluid can depend upon the denies this * 



oxidation of the metals, becaufe he found that the pile acted 



more powerfully when he ufed the muriate of ammoniac, than 



when a diluted acid was employed ; but the objection of the 



learned experimenter is fufficiently obviated by the confide- . 



ration fuggefted above. He farther alledges in fupport of his particularly be- 



opinion, that a pile with potafh interpofed between the plates f^J^*^^ 



acted very powerfully, though no oxidation was produced. I without oxida- 



have repeated this experiment, and have on the contrary uni-f l0n », 



r . * J but the contrary 



• proved to be the 

 * Or uncempenfated by its oppolite.---N. fact. 



formly 



