190 'I HE SCIENTIFIC PAPERS OF 



be taken into account. With the dynamometer in question the 

 measure was direct and absolute. While the machine was taking 

 its power it indicated the amount of power without loss. In 

 that way it was possible to get accurate results. The authors had 

 stated that one-half of the power was necessarily lost. It was 

 remarkable how nearly the best experimental results had come 

 up to the maximum. He believed that 49 per cent, had been 

 actually realised. He was not sure whether the theory in ques- 

 tion held good, that the maximum effect was produced when the 

 velocity of the machine that received the power, and gave it 

 off at the further station, was only one-half of the velocity of the 

 motor. He was under the impression, after some consideration, 

 that about two-thirds of the velocity would give the maximum 

 result. The subject, however, was too new to speak positively 

 on so intricate a point. Enough, he believed, had been said to 

 show that this method of electric lighting and transmission of 

 power was more than a mere speculation ; and that it had entered 

 the ranks of practical application of natural science. 



Dr. Siemens said he believed the flickering of the light was due 

 to imperfection in the carbons. No doubt if the moving power 

 at the distant station were uncertain, if it should vary in speed, 

 there would be cause for irregularities in the working, but at 

 present the carbons were the most imperfect portion of the whole 

 arrangement. They had been much improved, but were not yet 

 perfect. The difficulty, however, he thought, was not an insuper- 

 able one. With care and attention homogeneous carbons would 

 no doubt be produced. Every now and then foreign matter, when 

 it came to the front, would cause a little explosion and a little 

 separation in the piece of carbon, and so occasion a nickering. 

 In order to light a room electrically, at least two electric candles 

 ought to be used, so that the flickering of the one would melt 

 away, as it were, in the steadiness of the other. The room in 

 which the meeting was assembled was very unfavourable for 

 electric lighting. The screen put up to intercept the rays was an 

 imperfect one, and would allow a large portion of the luminous rays 

 to pass through. If there had been a whitewashed ceiling, and the 

 light were spread over its entire surface, the steadiness and in- 

 tensity of the light would have been much greater. With regard 

 to the question of cost, he believed the price of a machine of the 



