on a Permanent Electric Current. 167 
a 
action of magnets on conductors bearing currents. This being 
the case, it seemed desirable to make experiments with several 
strips of the same metal and determine whether the ratio 
am prove to be a constant for all. The dimensions of 
Mx 
EK 
many of the strips used, of whatever metal, are given below, 
and in order that the conditions to which they were variously 
arrows in fig. 2 show the direction of the transverse current 
relatively to the direct current in gold, the magnet ole, 5, 
being a south pole, i. e., the pole attracting the north pointing 
: : ih ; 
two currents and the magnetic force is the same in all of the 
four gold plates which have been examined in’ this particular. 
he same uniformity is observed in the four silver plates, and 
the three iron plates, which have been tested in the same way. 
With the two plates of tin which have been examined there 
has been a trifle of uncertainty upon this point, as the effect in 
this metal is at best very small, but this uncertainty is hardly 
sufficient to cast doubt upon the correctness of the rule that, so 
far as observation has gone, the relative direction of the trans- 
_verse current is always the same for any particular metal. This 
uniformity in so many cases could hardly be accidental. 
This matter of direction is evidently one of fundamental im- 
portance. ‘The direction was found to be the same for silver 
same as in gold. This fact will be discussed further on. The 
conductors which have, up to this date, been subjected to ex- 
* Am. Journ. Math., vol. ii, p. 355. 
