l6o 



ELECTRIC LIGHTING. 



maintain the equilibrium, and if too great a tension were 

 given to it the movement of the apparatus became too jerky. 

 This inconvenience has been got rid of by so arranging 

 the armature, to which a curved form is given, as to vary its 

 distance from the poles of the 

 electro-magnet. This motion is 

 produced by the friction of an 

 eccentric lever. This slight modi- 

 fication is shown in Fig. 40, which 

 represents the external appearance 

 of the apparatus. As the least 

 variation sensibly alters the effec- 

 tive power of the attraction, the 

 action of the electricity may then 

 be easily and very exactly regu- 

 lated, according to the power of 

 the electrical generator at a given 

 instant. 



In this new model the positive 

 pole may be placed above or below 

 as required. The -j- pole should 

 correspond with the upper carbon 

 for lighting purposes, and with the 

 lower carbon for optical experi- 

 ments, such as the combustion of 

 nnetals, &c. 



"This new regulator," says Du- 

 FIG. 40. boscq, " fulfils all the conditions re- 



quired for the application of the 



electric light to scientific experiments, and to the illumination 

 of lighthouses, vessels, workshops, theatres, &c. 



" In the present state of science the electric light is as com- 

 monly produced with the magneto-electric machine as with the 

 battery ; it may even be affirmed that the industrial generator 

 of the electric light is magnetic action : witness the electric 

 lighting of lighthouses, ships, yards, &c. It was therefore 



