468 Mr. Alexander Siemens [Feb. 26, 



ductor and a return conductor on the ground, wbicli can be either 

 the rails or an insulated conductor at practically the earth's 

 potential. 



Their idea of utilising the single-phase currents was to have a 

 single-phase motor driving a largo continuous current generator, and 

 a smaller one for exciting the fields of the generator '^nd of the 

 train motor. 



All this machinery is carried on the locomotive, which, therefore, 

 resembles a Heilmaun locomotive, except that the steam engine is 

 replaced by the single-phase motor. 



In this system the regulation of speed is e fleeted on the Ward- 

 Leonard plan by adjusting the strength of the magnetic field of the 

 continuous current generator. 



A very similar system has been carried out by the Oerlikon 

 Company for the electric railway between Seebach and Wettingen. 

 And they have kindly placed at my disposal some photographs of 

 the railway and of the locomotive, from which the slides have been 

 13repared. 



One feature which deserves attention is the form of the collector, 

 which is a curved bar turning round a horizontal axle on the carriage 

 and i^ressed against the conductor by a spiral spring. This arrange- 

 ment allows the collector to adapt itself to all the various positions 

 which the conducting wire may successively take up relative to the 

 moving carriage. 



It is, however, possible to use single-phase motors direct for the 

 propulsion of vehicles by reverting to the induction-motor, and this 

 has been done by Mr. Lamme, an engineer of the Westinghouse 

 Company in America, and by Dr. Finzi in Milan, and by the Union 

 Company of Berlin. 



This latter company is running such electric motor cars on an 

 experimental track about 4 km. long between Johannisthal and 

 Spiudlersfeld near Berlin. 



Their working current is 6000 volts, which passes direct into the 

 stator of the motors, while about the sixth part of the current is trans- 

 formed down for lighting and regulating purjjoses. 



The working conductor is supported by being connected at 

 intervals of 3 metres to a carrying wire, which has not much strain 

 on it, the object being that, in the case of the wire breaking, its ends 

 cannot touch the ground. 



The Union Company have kindly sent me some photographs of 

 the line, which fully explain the arrangements. 



Eeverting now to the Studiengesellschaft, which was formed in 

 November 1899, they resolved to carry out experiments for the 

 jmrpose of attaining a speed of 200 km. (125 miles) per hour, and to 

 utilise three-phase currents of at least 10,000 volts. 



The Allgemeine Elektricitiits Gesellschaft and Siemens and 

 Hiilske were requested each to design a motor car capable of accom- 

 plishing this speed in a satisfactory manner, and Mr. Lasche, an 



