magnetic phenomena produced by electricity. 17 
As bodies magnetized by electricity put a needle in motion, 
it was natural to infer that a magnet would put bodies mag- 
netized by electricity in motion ; and this I found was the 
case. Some pieces of wire of platinum, silver, and copper, 
were placed separately upon two knife edges of platinum 
connected w r ith two ends of a powerful voltaic battery, and a 
magnet presented to them ; they were all made to roll along 
the knife edges, being attracted when the north pole of the 
magnet was presented, the positive side of the battery-being 
on the right hand, and repelled when it was on the left hand ; 
and vice versa, changing the pole of the magnet. Some folds 
of gold leaf were placed across the same apparatus, and the 
north pole of a powerful magnet held opposite to them ; the 
folds approached the magnet, but did not adhere to it. On 
the south pole being presented, they receded from it. 
I will not indulge myself by entering far into the theoretical 
part of this subject ; but a number of curiPus speculations can- 
not fail to present themselves to every philosophical mind, in 
consequence of the facts developed ; such as whether the 
magnetism of the earth may not be owing to its electricitv, 
and the variation of the needle to the alterations in the elec- 
trical currents of the earth in consequence of its motions, 
internal chemical changes, or its relations to solar heat ; and 
whether the luminous effects of the auroras at the poles are 
not shown, by these new facts, to depend on electricity. This 
is evident, that if strong electrical currents be supposed to 
follow the apparent course of the sun, the magnetism of the 
earth ought to be such as it is found to be. 
But I will quit conjectures*, to point out a simple mode of 
making powerful magnets, namely, by fixing bars of steel 
- mdcccxxi. D 
