Reproduced by permission of the British Aluminium Co., Ltd. 



A MARVEL OF POWER TRANSMISSION BY OVERHEAD CONDUCTORS 



The 60 conductors seen make up 20 three-phase circuits, transmitting between them 200,000 horse-power at a pressure of 

 10,000 volts. The bare conductors are insulated from the supporting steel trestles by large porcelain insulators of very high 

 resistance. In this case they are of aluminium, a metal which is widely used for transmission lines. Current is now trans- 

 mitted at pressures up to 220,000 volts, and for power purposes over distances of up to 200 miles. 



Reproduced by permission from "Fifty Years of 

 Electricity" (The Wireless Press. Ltd.). 



A COPPER RING HELD OVER THE POLE OF 

 AN ALTERNATING CURRENT ELECTRO- 

 MAGNET IS STRONGLY REPELLED AND JUMPS 

 UP IN THE AIR WHEN RELEASED 



