1 2 2 ELECTRIC LIGHTING. 



estimated at 31 '3 per cent. ; and with . Siemens' machine, 

 having the least resistance of all, it reached 43-4 per cent. 

 By using a cable of less resistance, this loss was reduced to 

 23 per cent, with the Siemens machine, but it became 35 

 per cent, when, by coupling two Siemens machines for quan- 

 tity, their total resistance was reduced by one-half. The 

 employment of this cable of small resistance with one of the 

 Alliance machines caused a loss of 69-1 per cent, of the total 

 light, and with Holmes' machine the loss became 66 -i per 

 cent. With two Holmes machines coupled the loss rose to 

 76-5 per cent. These experiments show, therefore, that in 

 order to realize the conditions necessary for the maximum 

 of light, the resistance of the conducting wires must have a 

 certain relation to that of the machine. (See Note B). 



RESULTS PRODUCED BY COUPLING TWO MACHINES. 



According to the experiments made at the South Foreland 

 with coupled magneto-electric machines, it has been found 

 that the light produced by two coupled machines was more 

 intense than the sum of the lights produced by each acting 

 separately. Thus two Siemens machines having separately 

 given lights, the intensities of which were represented by 

 4,446 and 6,563 candles, supplied when joined for quantity 

 a light equal to 13,179 candles, or 197 per cent, more than 

 the sum of the lights produced separately. This result is 

 not peculiar to the Siemens machines, for the same occurs 

 with the Gramme machines ; but with the former it is much 

 more marked. These results are shown in the table on 

 pages 124 and 125. They prove that, as we have already 

 stated in page 1 1 9, as regards the luminous intensity, there is 

 a greater advantage in concentrating the electric action at a 

 single lamp than in dividing it among several. 



