[ 49 ] 
order to produce the electrical phenomena, 
that the metal fhould be in contact with 
the coating. 
If the conductor con lilts only of one 
metal, it is fufficient that its two extre¬ 
mities touch the water in the two glafles. 
But in a little time, its conducting fa¬ 
culty becomes fo much weakened, as not 
to give any apparent mark of the circula¬ 
tion of the eleCtrical fluid. In fome 
frogs even it is found ufelefs, although 
employed immediately after their prepara¬ 
tion. 
But if two different metals be fubffi- 
tuted as conductor, the movements will 
take place ; the power of this compound 
conductor, has, however, its limits j the 
electricity not palling in a fufficient quan¬ 
tity to put the mufcular fibres in aCtion. 
To produce this effeCt, it fhould be 
carried to the nerves by better conductors 
than water. Metals are the belt, and it 
E is 
