

TELPHERAGE 265 



difference could be detected when the deflection was materially 

 reduced. This resistance was measured by pulling a train along, 

 span after span, by one end of a rope passing over a pulley on 

 the leading truck, and having a weight hanging vertically from 

 the other end of the rope. The weight thus limited the pull. 

 This pull differs extremely little as the train moves along, for 

 when one part of the train is descending the curve the other 

 part- is ascending. It should be noted that during this experi- 

 ment no special care had been taken to oil the bearings, and I 

 have no doubt this pull can be materially reduced. I have 

 ventured to dwell at some length on the mechanical problems 

 involved in this form of telpherage, because the experiments 

 made so far have chiefly borne on questions of mechanics. The 

 makers of dynamos can put at our disposal apparatus which 

 will generate day after day, with perfect certainty and regularity, 

 currents of electricity such as will transmit the horse-power 

 generated by powerful steam-engines. These makers have 

 already solved the chief electrical problems which present them- 

 selves in connection with telpher lines. They can give us at will 

 constant current or constant electromotive force, high or low, as 

 we may choose. They are now able to arrange their apparatus 

 so that any number of incandescent lamps may be turned off or 

 on, without disturbing the regularity with which other lamps 

 are supplied ; and by the same arrangement we are enabled to 

 start or stop any number of telpher trains without disturbing 

 the running of others. The electrical problems of the telpher 

 line and those of electric lighting run in absolutely parallel lines. 

 The electric motor, although it may be termed a mere inversion 

 of the dynamo, has not as yet been brought to equal perfec- 

 tion ; but month by month improved designs, proportions, and 

 materials are being introduced, and the result already attained 

 is sufficient for our purpose. It is all the more encouraging 

 to feel that these results will certainly be surpassed and far 

 surpassed in the immediate future. 



The following short summary of the problem of the trans- 

 mission of power by means of electricity may interest those who 

 have not studied the subject. There are three steps in this 

 transmission 1st, we convert mechanical power into electricity 

 by means of a dynamo ; in doing so we incur a loss of from 10 

 to 20 per cent. ; 2nd, this electricity, in flowing along a con- 



