$6 ELECTRIC LIGHTING. 



of which are wound the induced coils. These coils are 

 wound to the shape of a spindle with a curvature so calcu- 

 lated that the four angular parts of the cores are nearly on a 

 level with the external spires of these different coils, and 

 therefore are able to pass the inducing poles at a very small 

 distance. The frames are also so arranged that the angular 

 and uncovered parts of the cores retire from each other so as 

 to present themselves conformably to a spire of a coil. It fol- 

 lows that the magnetizing actions are produced successively, 

 and that the currents due to these actions, as well as to that 



between the wires of the coils, 

 are always of the same inten- 

 sity in the different phases of 

 each revolution of the ring. 

 The induced coils are, more- 

 over, wound in directions al- 

 ternately reversed, in order to 

 obtain currents in the same 

 direction in each half of the 

 ring. Finally, these coils are 

 joined to a collector exactly in 

 FIG. 31. the same way as in Gramme's 



and in Siemens' machines, 



and this arrangement allows continuous currents to be 

 obtained. 



The inducer has also the same arrangement as that of the 

 Siemens machines, and the induced current traverses it in 

 its entirety as in those machines. 



Experiments made in my presence at Geneva, in the work- 

 shops of Turetini, who is the maker of these machines, 

 showed that they have for a given velocity exactly the same 

 luminous power as the ordinary form of Gramme machines, 

 but they have the advantage of becoming very much less 

 heated. In fact, it may be said that they are hardly heated 

 at all. As regards construction, they also present some 

 advantages; thus, for instance, the uncovered parts of the 



