4 6 



ELECTRIC LIGHTING. 



MAGNETO-ELECTRIC GENERATORS. 



The method of generating electricity by chemical action, 

 and especially by the oxidation of zinc, is, as will presently 

 be seen, extremely costly, and if this were the only way of 

 producing the electric light, that method of illumination 

 could not be entertained; but it is not the only way, for, 



thanks to the powers of induction, 

 generators of the light have been 

 formed which require nothing- 

 more than motive power, and this 

 brings the production of electri- 

 city to the matter of a greater or 

 less consumption of coal, which 

 is of all chemical reactions the 

 simplest and cheapest. In this 

 respect the results obtained have 

 exceeded all expectations, and it 

 may be said that if the solution 

 of the problem depended only on 

 the production of electric action, 

 it has now been almost realized ; for, light for light, the cost 

 of illuminating in this way would be ever so much less. But 

 the question is, as will be seen, much more complex, and until 

 we have treated it from the various points of view that re- 

 quire to be taken into consideration, the generators founded 

 on the effect of induction will engage our attention. 



History of the Question. When a voltaic current cir- 

 culates spirally round a core of iron, steel, or any magnetic 

 substance, the latter is magnetized, and, with certain mag- 

 netic substances possessing, like iron, a non-persistent coer- 

 cive force, this magnetism disappears as soon as the current 



FIG. 10. 



