272 



ELECTRIC LIGHTING. 



minute, and expends 4 H.-P. the light produced varies from 

 1,000 to 2,000 lamps. In the second case it makes 1,200 

 turns, employs 8 H.-P., and gives light equal to from 2,000 to 

 2,500 lamps. When the weather is clear, the machine is 

 joined up for quantity, and the expenditure of steam is then 



FIG. 71. 



small, the working easy, and the carbons are consumed 

 slowly. When the weather is foggy and thick, the machine 

 is arranged for tension, the expenditure of steam increases, 

 the working requires rather more care, and the carbons are 

 consumed quickly. With the Brotherhood motor the change 

 of power is effected instantaneously. 



For war signalling, Gramme has fitted up a small machine 

 which can be worked by a man's arm. This machine. 



