1912] on Electricity Sttpply : Fad, Present and Future. 1-45 



CommDUwealth Electric Co., of Chicago, in America, for their Fisk 

 Street Station, the order havinij; come to this country mainly by reason 

 of the superior economy guaranteed, the figure that it is confidently 

 expected will be obtained being something like ten per cent, lower 

 than anything that has previously been obtained with steam plant. 

 This ten per cent, economy in steam, with a plant of these dimensions, 

 means a saving of about two tons of coal per hour when working at 

 full load. 



As will be observed from the sectional drawing, the turbine is 

 divided into two. The steam first passes from one end to the other 

 through a high-pressure part, where the blades are shown as made of 

 copper, which is better suited to stand super-heat than the usual 

 bronze. Next, the steam is carried to the centre of a low-pressure 

 turbine, where, just as was the case in the original Parsons machine, 

 it divides, and passing partly to the right and partly to the left, 

 finally reaches the surface condenser, which has a cooling surface of 

 about 39,000 square feet, and is made part of the machine so as to 

 avoid all losses in connecting pipes. The speed of the machine will 

 be 750 revolutions per minute, and the steam pressure employed 

 200 Ibs.per square inch with 200" F. normal superheat. 



In electricity supply the next most important thing after economi- 

 cal generation is obviously economical transmission and distribution, 

 and in relation to these latter considerable advance has been made in 

 recent years, more especially in the direction of employing very high 

 voltages, which enable great distances to be covered with compara- 

 tively little loss. There used to be great prejudice in this country 

 against the use of overhead wires, but this is disappearing, particu- 

 larly in industrial districts where the aesthetic point of view does not 

 count. 



In America and in Canada, notably by the Ontario Power Com- 

 pany, pressures as high as 100,000 volts are in use on overhead lines, 

 and similar voltages are at present being adopted in Germany in one 

 instance. In the ordinary way consumers are all connected up in 

 parallel, exactly as was shown in the diagram attached to Lane Fox's 

 early specification, but, of course, using a metallic and not an earth 

 return. A very interesting method in which the consumers are all 

 joined in series, instead of in parallel, has, however, been worked out 

 in Switzerland by Mr. Thury, and is largely adopted in Geneva. It 

 has now been applied by Mr. Highfield for the Metropolitan Company 

 in the outskirts of London. 



In the latter case there are seven miles of cable constructed to 

 carry 100 amperes and up to 120,000 volts continuous current ; the 

 sub-stations, where there are motor generators, taking a voltage 

 dependent upon the power required, being placed all in series. The 

 ultimate capacity of the circuit is 10,000 kilowatts running at 

 100,000 volts and 100 amperes. At present only 1500 kilowatts are 

 being transmitted with 15,000 volts. The voltage will be raised from 



