Viilla on Annual TJeclndty. 6'j 



wc lliall now try what will be the refult, accorduig to my 

 principles, with four pieces of metal, two of which are of 

 one kind ; for example, zinc, when connefied with moiil 

 condu(Stors of difierent kinds. 



I {hall firll obferve, that when they are connefted in a cir- 

 cle, as at fig. II, the powers which endeavour to put the 

 electric fluid in a ftreaming movement will be oppofed to 

 each other, and in perfe6l equilibrium, and thai confequent- 

 ly no movement can take place in the frog, here fuppofed to 

 be the moift conduclor a or a part of it, however irritable 

 and well prepared it may be ; and if the experiment be made 

 with accuracy and the neceflary precaution, fo that the me- 

 tals, in particular, be very clean and dry at the points of con- 

 tact, it will perfectly confirm what I have above faid : the 

 frog will experience no agitation, no convulfive movement. 



Thefe movements, on the other hand, took place, as might 

 be forefeen from my principles, as often as I omitted one of 

 the middle pieces, or changed the order. 



Thc conductors of the fecond clafs, which in all the figures 

 are denoted by fmall letters, may be cups with water, in which 

 the ends of the pieces of metal denoted by the large letters are 

 inimcrfed ; or fponges or other bodies which have imbibed 

 aqueous moifture. They may be either large or fmall ; and 

 may confilt of one or more pieces, provided they be in pro- 

 per contaft : they may alio be perfons, if their fkin be moift- 

 ened at the places of contaft, &c. By the laft method the 

 experiments v.ill be very beautiful and inceflluit, when the 

 circle conuds of three or more perfons (I have formed it fre- 

 quently often and even more), of two or more frogs pro- 

 perly j>rcpared, and of four pieces of metal, two of filver and 

 two of iron, tin, and particularly zinc. The change of 

 efleft, when you cliange the connexion, is ftriking. 



Let the pofition be as rcprefentcd in fig. 12, where g is 

 the prepared frog, which the two perfons />, f, hold in their 

 hands, one on the one fide by the leet, and the other on the 

 oppolite by the rump. Z, Z are two. plates of zinc, whi^ih 



