.SYA 1 \\-ILUA.M .s/AM//:.\-.s, I-'.R.S. 189 



ling caloric motors, and with an expenditure of fuel certainly 

 not greater ; because, although perhaps only 40 per cent, of the 

 power exerted at the central station was actually obtained at the 

 further station, it was nevertheless obtained at a very low rate. 



!A lo. i 111*, engine, economically constructed, would produce 1 III', 

 with less than :> Ibs. of coal ; whereas a small motor of '1 or 3 HP. 

 would consume probably 6 to 8 Ibs. of coal per HP. per hour. 

 ng that difference in mind, the magneto-electric engine would 

 be an economical one. How far the principle might be applicable 

 ultimately, for the utilisation of such natural forces as water-power 

 from a distance, remained to be seen. The difficulty was in regard 

 to the length of the electrical conductor. Its resistance increased 

 in the ratio of its length ; and as the increased resistance would 

 mean loss of useful effect in the same proportion, it would be 

 necessary to double the area of the electric conductor in doubling 

 its length, in order to maintain the same ratio of efficiency ; but 

 if that were done, the resistance might be increased to many miles, 

 and he believed profitably, without further loss of power. 



He desired to direct attention to the dynamometer employed in 

 the experiments to ascertain the power consumed in the magneto- 

 electric machine which received the power of the engine. The 

 first experiments, made by indicating the steam-engine with the 

 machine on, and w r ith the machine off, gave very imperfect results ; 

 but a dynamometer had been contrived which he thought was of 

 sufficient interest to be brought before the Institution. The belt 

 that drove the machine was nipped between two pulleys, which 

 rested in a slide and were held by a spring adjustment and screws. 

 I f the resistance increased, one side of the belt tended to become 

 straight, and it could not become straight without pulling in the 

 slack side of the belt ; but it was held back by the elastic pressure 

 on the slide crossways, which indicated the amount of force 

 necessary to pull the strap straight ; and that simple indication, 

 multiplied into the number of revolutions, gave the absolute 

 measure of the power transmitted. The want was often felt of 

 such means of telling how much power a machine consumed. It 

 was not sufficient to say, " If we stop it we shall see how much 

 power the steam-engine indicates, and how much it indicates 

 when working ; " because between the two there was the friction 

 of the machine, and there were all sorts of disturbing elements to 



