ALTERNATE CURRENT DYNAMO-ELECTRIC MACHINES. 
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the magnets with the copper plates in and the copper plates absent. A comparison 
shows that the copper plates do not make a great deal of difference. The principal 
effect is to diminish the current induced in a coil on the magnet placed at position 5, 
fig. 1, close behind the copper plate. 
It may be inferred that in this machine there is conductivity enough in the 
magnet cores to have in large measure the effect indicated, and that the effect cannot 
