056 



THE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



by the wires /, /', /", have their extremities placed in the same relation 

 to the teeth of the wheel as the bobbins to the armatures of soft 

 iron. When two armatures are exactly opposite, as at E E, the spring 

 r, communicating witli the electro-magnets E E, is in advance of a 



FIG. 427. Fromeut's electro-motor: the action of the currents upon the ;irmatures. 



tooth which it has just quitted, while r touches the preceding tooth 

 and closes the circuit in the coils E' E'. After the twenty-fourth 

 part of a turn r quits the tooth, and then r", by touching one in its 

 turn, throws the current into the bobbins E" E". In one word, the 

 circuit will be closed at each -^tli of a turn, and will pass by the spring, 



-a- 



Fiu. 428. Distribution of Fronient's electro-motor. 



in contact with a tooth, to the bobbins in front of the armature by 

 the same angular distance. The current returns to the negative pole, 

 after having excited each pair of .magnets, by a common wire. It 

 does not cease moreover to act on one electro-magnet, until it has 



