TKANSACTIONS OF SECTION G. 855 



to private consumers for industrial purposes Las not yet made as much progress as 

 might have been expected. Perhaps electrical engineers have been so busy with 

 problems of electric lighting that they have had no time to settle the corret^pond- 

 iug problems of power distribution. 



No doubt continuous current distribution presents at the moment the fewest 

 difficulties, or, at any rate, involves the fewest comparatively untried expedients. 

 Several continuous current plants for distributing power are in operation, of which 

 perhaps tlie most interesting is that at Oyonaz, which was described in Section G- 

 last year by Professor G. Forbes. There 300 horse-power obtained by turbines is 

 transmitted 8 kilometres at 1,800 volts. It is then let down by motor transformers 

 to a voltage suitable for lighting and driving motors. A number of small work- 

 shops are driven, the power being supplied at a fixed rent. 



At the Calumet and Hecla mines on Lake Superior, at the Dalniatia mines in 

 California, and some other places, energy derived from turbines is transmitted 

 distances of a mile or two by continuous electric current-', and used in driving 

 mining machinery, and some cases of the use of electiical distribution in mines in 

 this country were mentioned by my predecessor in his Address last year. 



At Bradford a few electric motors are b'jing worked from the electric lighting 

 mains. The largest of these is of 20 hovse-power. The price at which the elec- 

 tricity is supplied is not given, but I believe the cost is high when reckoned for 

 continuous working. It would seem that it must be so when the electric current 

 is generated by steam-power. 



At Schaffhausen an electric transmission has now been constructed alongside 

 of the wire-rope transmission. The power is derived from two turbines, and is 

 transmitted across the Rhine, a distance of 750 yards, at 024 volts. The current 

 drives a spinning-mill, in which the largest motor is 3.^0 horse-power. The power 

 is sold, I believe, at '31. per horse-power of the motors per aimum. 



Many engineers have now apparently come to the conclusion that alternating 

 currents will be better for power transmission to considerable distances than con- 

 tinuous currents. One interesting alternate current transmission, partly for power, 

 partly for lighting purposes, has been for some time in operation at Genoa. 



On the line of the aqueduct bringing water from the Gorzente rivulet three 

 electric stations are being established. The reservoirs are i?,050 feet above Genoa, 

 and as this is a much greater fall than is required Jor water-supply purposes, part 

 can be used to generate about 1,600 horse-power. 



In the first of the power stations erected there are 1 urbines of 450 horse-power 

 driving two dynamos. A second larger station was completed in November. In 

 this there are eight alternate current dynamos of 70 horse-power each. Six alter- 

 nators are worked in series, transmitting a current of G,0CO volts. The current is 

 transmitted sixteen miles by bare copper wires, 8'0 mm, diameter, placed overhead. 

 The current is used both for lighting and power purposes. 



Another method of using alternating currents was adopted in the remarkable 

 experiment at Frankfort last year. In that case energy obtained by turbines at 

 LaufTen was transmitted to Frankfort, a distance of 108 miles, and used for 

 lighting and driving a motor. The current was obtained at low tension, trans- 

 formed up to a tension of 18,000 to S7,000 volts for transmission, and then trans- 

 formed down again for distribution. The loss in the conducting wives ranged from 

 5 horse-power, when the turbines worked at 100 horse-power, to 25 horse- power, 

 when the turbines worked at 200 horse-power. The efficiency of dynamo, two 

 transformers, and line ranged from 08 to 75 per cent.— a remarkably satisfactory- 

 result. 



There can be little doubt that if efficient and durable transformers can be con- 

 structed, they do give a considerable advantage to an alternate current system. 

 To an ordinary engineer it appears also that the system of producing current at low 

 tension in the dynamo, and using it at low tension in the motors, permits the con- 

 struction of dynamos and motors more mechanically unexceptionable than those 

 working at high voltage. 



I have spoken of the growth of a demand for power distributed in a convenient 

 form in towns. The power distribution in London, Manchester, Birmingham, 



