Associated cases of Current and Static Effects. 91 
Miles per second. 
* Wheatstone, in 1834, with copper wire made it 288,000 
* Walker, in America, with telegraph iron wire 18,780 
*O’Mitchell, do. do. do. 28,524 
_* Fizeau and Gonnelle (copper wire) - - 112,680 
e iron wire) - - - 62,600 
0. : 
t A. B. G. (copper) London and Brussels Telegraph 2,700 
t Do. (copper) London and Edinburgh Telegraph 7,600 
Here the difference in copper is seen by the first and sixth re- 
sults to be above a hundred fold. It is further remarked in Lie- 
big’s report of Fizeau and Gonnelle’s experiments, that the 
velocity is not proportional to the conductive capacity, and is in- 
dependent of the thickness of the wire. All these circumstances 
and incompatibilities appear rapidly to vanish, as we recognize 
and take into consideration the lateral induction of the wire car- 
tying the current. If the velocity of a brief electric discharge 
1s to be ascertained in a given length of wire, the simple circum- 
stances of the latter being twined round a frame in small space, 
or spread through the air through a large space, or adhering to 
walls, or lying on the ground, will make a difference in the re- 
sults, And in regard to long circuits, such as those described, 
their conducting power cannot be understood whilst no reference 
1s made to their lateral static induction, or to the conditions of 
intensity and quantity which then come into play ; especially in 
the case of short or intermitting currents, for then static and dy- 
namic are continually passing into each other. 
It has already been said, that the conducting power of the air 
and water wires are alike for a constant current. This is in per- 
fect accordance with the principles and with the definite charac- 
ter of the electric force, whether in the static, or current, or tran- 
Sition state. When a voltaic current of a certain intensity is sent 
®mes proportionate to the battery intensity, an 
equals that in the air wire, in which the same state is (because of 
the absence of lateral induction) almost instantly attained. Then 
of course they discharge alike, and therefore conduct alike. 
_Asstriking ‘proof of the variation of the conduction of a wire 
by variation of its lateral static induction is given in the experi- 
er 
Liebig and Kopp’s Report, 1850 (translated), p. 168. 
t Atheneum, January 14, 1864, phon ; 
