ON THE ELECTRIC COLUMI^r. 



91 



the whole column being now in this state [Exp. 8, 1.), hxA 

 they fall in purt, when the gold leaf strikes at the zinc side, 

 and rise in the intervals of tlie strikings; thus pointing ont 

 clearly a current flowing from B to A, at a higher level 

 than \.\\e standard, which level alternatelj- rises nTud falls. 



3. When the adhesion of the gold leaf takes place at A, 

 the 2/«c side; which civcunistaiice, producing a continued 

 communication of this side with the ground, renders the 

 column negative in the whole (Exp. 8, 2.) ; while the ^old 

 leaf at B, the copper side, goes on striking; a current of 

 electric Jiuid is also produced, but at -a lower level than the 

 standard: the divergence of the gold leaves in the middle 

 electroscope is consequently negative, and, as in the former 

 case, they full in part at every striking, and rise in the in- 

 tervals; but while in that case they fell by the lowering of 

 level of the c arcnt, and rose when it came Mgl^r; now di» 

 verging as negative, they Jail at every striking, because 

 fiome jftuid, ascending from the ground, makes the cohuna 

 less negative; and they rise again while this fluid flows into 

 the ground by the zinc side, and thus prepares another 

 striking. 



I have made the same experiments on the motions of the Motinns of th« 

 electric fmid within the pile itself; they are more confused fiii'*^ i" the 

 and less lasting on account of the calcination of the medals: fused and les«' 

 but the column, being in fact the electric machine of the ^^•'^ling- 

 pile, shows clearly and permanently these motions, which I 

 shall now follow in the circuit, or when the two extremities 

 of the column (or the pile) are connected together by some 

 interrnediate body. In this case the motion of the electric 

 Jluid is manifested by more or less retardation of its current, 

 according to the degree of conducting faculty of the body 

 employed. 



For this class of experiments (see X\\ejigvre) brass hooks, Ad<' t .nal ap- 

 5 and 6, are fixed to the small brass plates, terminating paraius. 

 the column at each extremity, and against which press the 

 screws: these hooks project a little more than an inch, and 

 s^rve for different purposes. The following experiments 

 will relate to the conducting faculty of that kind of glass 

 tube filled with water, entered by wires on both sides, in 

 which chemical effects are produced when it is a^'plied to 



th.e 



