Magneto-Electricity, and Electro-magnetical Machines. 129 
ments, and instead of changing the torsion so as to obtain an 
equal number of revolutions, I let the torsion remain constant and 
changed the number of revolutions to produce equal deflection, 
and found that to maintain a torsion of 624°, required sixty revo- 
lutions per minute in one case and ninety in the other, which 
being nearly in the inverse ratio of the deflecting forces, I infer- 
red that the deflecting forces are as the number of reversals in a 
given time. 
gees => Explanation of “e Figure. 
ns. The electro etical dipping: , fastened to an axis ied in the 
two brass columns, E and F. 
A. Ts copper circles or wheels, to which are soldered the two ends of the 
coil 
B. A block of ivory having two mercury grooves, in which play the two pairs 
of semicircles of copper, C 
D. The support of the ivory 
NS. The semicircular magnet, supported by the wooden column, W. 
—No. 1. 17 
Vou. X 
