ANIMAL ELECTRICITY. 233 
convulfions were much lefs obfervable, when lead, iron or cop-. 
per were fubftituted inftead of thefe. 
EXPERIMENT II. 
I next tried all the above mentioned experiments: with one 
half-crown piece only, placed oppofite to the tinfoil; and on 
prefling the tinfoil againft the filver-piece, by means of a brafs- 
wire which I held in my hand, I found, that the mufcles: were 
convulfed exactly in the fame manner as where two. pieces. of 
the filver were employed in the manner before mentioned. 
EXPERIMENT JII. 
I rounp likewife, that the experiment fucceeded equally well, 
ie. although the filver-piece did not touch the bedy of the animal; 
but was merely brought into conta¢t with the tinfoil put around’ 
the nerve, by preffure with a brafs-wire held in the hands 
EXPERIMENT IV. 
_ Arrer inclofing the upper part of the fciatic-nerve-in tinfoil, 
I tied a linen-thread around it, where it is about to-pafs from: 
the trunk into the thigh, fo tight as to deprive the mufcles of 
their power of a¢ting by the ordinary exertions of the animal, 
-and the fkin and toes of their feeling, yet when, with a brafs- 
wire held in my hand, I prefled the tinfoil againft the filver- 
piece, the mufcles of the limb. were violently convulfed, 
Vo, Ill. Gg Exp s- 
