ELECTRIC LIGHT. 



267 



by an armature, which is, in its turn, adjusted by the screw, D. When it 

 happens that the magnetic force is reduced the spring acts and permits the 

 points to approach again, and the light is rekindled ; the carbons are then 

 locked till required to move. The second illustration (fig. 268) shows a 

 section of the lamp with the wheel arrangements for controlling the advance 

 of the carbon points as they waste away. 



In the " Brush " light, which is in use in London, and is fitted for large 

 spaces, the carbon points are held by a 

 regulator side by side, and they last 

 eight hours without renewal. The 

 power is generated by an electro- 

 dynamic engine. We give illustra- 

 tions of the lamps of Wallace and 



Fig. 269. Wallace lamp 



Houston (figs. 269, 270). The current 

 is conveyed through b and the mag- 

 net, m. The armature, a, separates the 

 electrodes, and the weakened current is 

 restored by b t and the light continues. 

 The pillar, /, is hollow, with a wire 

 running through it. The positive elec- 

 trode is supported by J, the negative by c; V is a button which comes 

 in contact with the lever, T, when the carbon points are exhausted, and 

 cuts the lamp out of the circuit by passing it direct through mercury cups. 



The Jablochkoff candle and chandelier are also represented (figs. 271, 

 272). The candles consist of carbons connected at the top, but otherwise 

 insulated, and fixed in a socket. They do not last very long without 

 renewal. The exhibition at the Crystal Palace will be essentially an Electric 

 Light Exhibition, and all the latest forms can be studied there. The great 

 attraction will doubtless be, as at Paris, the varied and numerous inventions 



