302 HISTORY OF GALVANISM. 



ticularly diftinguifhed himfelf by his afliduity in varying the 

 experiments. Dr. Monro wrote upon the fubject, and the 

 National Inftitute of France publiflied an elaborate report, 

 drawn up by a Committee compofed of feveral of its moft 

 learned members. As however thefe works do not appear to 

 contain any facts which materially illuftrate the nature of the 

 galvanic influence, or lead us to form any more accurate no- 

 tions refpecting its operations, we fliall in this brief fketch 

 FabronI: that only notice the papers of Fabroni, of which an account may 

 merely a^he- * )e f° und m tne 4tn Vo *- °f Nicholfon's Journal. He deduces 

 mical phenome- from his experiments that galvanifm is intirely a chemical 

 phenomenon ; he finds that metals become oxidated when in 

 conta6twith each other in circumflances where this would not 

 take place if they were kept feparate. This idea he confirms 

 by many obfervations and experiments, and fuppofes that 

 when the galvanic influence is excited by the action of two 

 metals that a chemical affinity is exerted ; he does not how- 

 ever point out very clearly in what manner the chemical ac- 

 tion which is exerted by the metals can be connected with the 

 phenomena of galvanifm. 

 Hiftoryofthi* In the year 1789, Cavallo publiflied a new edition of his 



JJ^EIearicit 31 ," Ele ft ricitv > and hc added a g ood account of the principal 

 and the Supple- facts in galvanifm ; an ample hiilory of this fcience m3y be 

 ment to the En- a [f f 0U pd \ n the Supplement to the Encyclopaedia Brilannica. 



cyclopaedia Bn- \ , , , r i V 



tannica. -1" "lis itate our knowledge of galvanilm continued until 



Grand difcovery the beginning of the year 1 800, when Volta made his difco- 



VoIta. P,e ^ verv °f tne apparatus ufed called the Galvanic Pile. In the 

 Phil. Tranf. for that year is a letter from Volta containing an 

 account of the pile, and a detail of many curious experiments 



Defcription. which he had performed with it. This inftrument confifts of 

 a number of circular pieces of two different metals, laid alter- 

 nately upon each other, with a piece of moiflened pafieboard 

 or fkin interpofed between each pair. The metals which 

 anfwer the belt for this purpofe are zinc and filver, which 

 were found to be the moll powerful in exciting the mufcular 

 contractions in the former experiments. If the two pieces of 

 metal which form the extremities of the pile be grafped firmly 



Galvanic /hock, in the hands previoufly moiflened, a fhock will be felt through 

 the hands and arms, more or lefs powerful in proportion to 

 the fize of the pile. This /hock may be repeated a^ long as 



the' 



