I. 
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iW 
} 
bm 
B. Heavy Current. 
The provision of electrical energy at as low a price as pos- 
sible must be the aim of all countries, as this is an essential 
condition, upon which the adoption of electricity in all branches 
of industry depends. Modern practice tends to seek the solution 
of the problem in the erection of high power central stations, 
which are erected at the actual source of power, in adapting 
the supply to suit the most divergent uses and in attaining 
the most complete and efficient utilisation of the power 
available. The linking up of coal driven stations with water 
power stations is progressing from year to year, owing to the 
increase in the voltages used for transmission. The range over 
which, thanks to modern high tension lines, current can be 
transmitted, extends the sphere of heavy current distribution 
beyond national boundaries, and power supplies of different 
countries can now be linked up to supplement each other. 
During the year 1908, a pressure of 110000 Volts was first 
used for transmission in America. In 1921 the transmission 
pressure was increased to 220000 Volts. In Germany even 
higher pressures are now being adopted. 
The line at present under construction for linking up the 
South German Water Power District with the Rhineland 
Brown Coal District, using 220 ooo Volts, is so designed that 
it can be used later on for 380 000 Volts without alteration. 
For this purpose it has been necessary to design hollow copper 
cables which provide the large superficial area of slight cur- 
vature, as required for such ultra high tension alternating 
current. “With this transmission pressure of 
280000 Voltis, loads from several hundred 
thousands up to a million kilowatts can 
be transmitted over distances of 500 to 
1000 kilometers. This brings the idea of an inter- 
national linking up of water and steam power plants within 
the range of practical possibility, and entirely new prospects 
are thus opened up for international co-operation 
in the sphere of power generation New 
technical and industrial ideas have to be considered. For 
instance, it is proposed to accumulate unused