64 



60 miles of tower line as approximately $17,000, with a salvage on. 

 aluminium from the other two lines at 52 cents a pound f.o b. Butte 

 railway station, of approximately $60,000."* 



Respecting the proportion of aluminium and copper used in high 

 tension lines, — 70,000 volts and over — data compiled from a tabular 

 statement in the Electrical World'\ show that, in 1914, North America 

 had some 7,000 wire-miles of aluminium against some 19,000 wire- 

 miles of copper in use on lines operating above this voltage. In other 

 parts of the world, the table shows no aluminium used on lines of over 

 70,000 volts. This is partly owing to the fact that there are compara- 

 tively few lines outside of America operating under these higher 

 voltages, but aluminium is also extensively used on the shorter lines 

 found there, notably in Norway, Sweden and New Zealand. 



Canada probably has in use a greater proportion of aluminium 

 lines than any other country. A recent survey by the Commission of 

 Conservation shows that on all lines in the Dominion, operating at 

 10,000 volts and over, there are 13,000 wire-miles of aluminium and 

 8,000 wire-miles of copper. 



* Electrical World, Feb. 24, 1917. 

 t Electrical World, April 25, 1914. 



