588 



THE POPULAR SCIENCE MONTHLY. 



Thus the revolving armature presents two groups of coils, gener- 

 ating two equal but opposite streams of electric force. The wire being 

 unbroken, the currents neutralize each other, and there is no circula- 

 tion. The result may be likened to what would be produced by taking 

 two batteries, each of 20 cells, and connecting them in opposition by 

 joining similar poles. 



The problem now is to pick up these dormant currents and utilize 

 their force. Its solution is apparent from the comparison we have just 

 made. To collect the electric current from two batteries which are 

 connected together in opposition, it is only necessary to fasten con- 

 ducting wires to the two points of contact of similar poles, when the 

 whole force of the batteries will flow along these wires. They were 

 hitherto opposed, they now flow together, quantity-wise. M. Gramme, 

 in the second portion of his invention, has adopted this artifice in an 

 ingenious manner. 



Fig. 4. 



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33 



i/: 1 ' 'w 



a ' ~ 



The various sections ot the continuous electro-magnet are con- 

 nected with radial jueces of copper shown at R in Figs. 3, 4, and 7, 

 insulated one from the other, but coming very close. The termination 

 of one coil of wire and the commencement of the adjacent coil are 

 soldered to the same radial connector, of which, therefore, there are as 

 many as there are coils. These radial connectors, on approaching 

 the centre, are bent at right angles, as shown at R, Figs. 4 and 7, and 

 pass through to the other side, where their ends form an inner con- 

 centric circle, being still insulated one from the other. 



The friction-pieces F (Figs. 4, 5, and 6), consisting of disks of cop- 

 per, are pressed, by means of springs shown at r (Figs. 5 and 6), against 

 the circle formed by the extremities of the conducting radii R, at two 

 points which are accurately in the equatorial line ; that is to say, at 



