From the "Romance of Modern Electricity" (Seeley, Service 6* Co.). 



A VIVID FLASH OF FORK LIGHTNING TAKEN OVER HOUSE-TOPS 



The lightning discharge is exactly similar to the spark from an electrical 

 machine, but on an immensely grander scale. Lightning is but an electric 

 spark which may be miles in length: it passes between cloud and the earth, or 

 from cloud to cloud. A wall-known authority has estimated the average dura- 

 tion of a flash as five-millionths of a second, and its average power at 25.000,000 



h. P . 



J 



By permission of Underground Electric Railways Co., Ltd. 



HOW AN ELECTRIC TRAIN PICKS UP CURRENT 



Touching the rail between the wheels is seen a cast-iron shoe, with curved-up ends, which 

 is dragged along in contact with the rail. Current enters the motors through similar shoes 

 touching an insulated rail (not visible) between the tracks. The current then passes out 

 through the shoe shown to the running rails, which are bonded together to act as return 

 or negative conductor. 



