414 Electro-Magnetic Experiments. 
action of the conjunctive wire of a galvanic battery upon a magnetic 
needle. 
The south pole of the magnet presented opposite results, the effects 
produced by removing the coil were such as would have occurred in 
replacing it upon the north pole. 
As the removal of the coil produces a contrary effect from that ob- 
tained when it is placed upon the pole, the representation is complete 
from the opposite magnetic currents produced in these cases. When 
the coil is drawn along the magnet towards the north pole, it is easy 
to conceive that passing successively to more magnetic parts, or ex- 
posed to magnetism of different intensities, the current of magnetism 
with regard to the wire is from south to north; this, by the reversion 
of the hypothesis in relation to the galvanic current, produces (since 
the north pole is towards the operator,) an electrical current from west 
to east, or from left to right, below the magnet. ‘The same is true for 
the south pole. 
We conclude that the effects of a magnet upon a coil of wire may 
be represented by an electrical current at right angles to the direction 
in which the wire moves upon the magnet, and directed below the mag- 
net from west to east when the coil is moved from the south pole to the 
north pole of the magnet, and vice:versa, the poles of the magnet 
being turned to the south. 
The denominations will change of course if it be considered more 
convenient to turn both poles to the north. 
It would seem easy to bring the facts relating to the removal of 
the keeper upon which wire is coiled, under the same expression. 
In that case the magnetism is in motion with respect to the coil, leay- 
ing the soft iron which forms the keeper. 
With fifteen turns of copper wire upon the prismatic keeper of the 
magnet before used, a vibration through twenty degrees, at the maxi- 
mum, was produced: beyond this the power of the current could 
not carry the needle. ‘The wire was wrapped with silk. 
With five turns upon the same keeper a vibration through an are of 
ten to twelve degrees was obtained. 
The coil being at rest upon the magnet no permanent deflection is 
produced. ‘This agrees with an observation of Nobili and Antinori. 
The amount of vibration may be easily increased by providing two 
coils, one for each pole, the direction of the coils being opposite to 
each other, the outer wires of each coil being united as well as the 
inner ones, the effect of two coils would be produced. ‘They may 
