452 FRAGMENTS OF SCIENCE 



between the voltaic battery and its generated heat. The 

 electric current is to all intents and purposes a vehicle 

 which transports the heat both of muscle and battery to 

 any distance from the hearth where the fuel is consumed. 

 Not only is the current a messenger, but it is also an in- 

 tensifier of magical power. The temperature of my arm 

 is, in round numbers, 100 Fahr., and it is by the intensi- 

 fication of this heat that one of the most refractory of met- 

 als, which requires a heat of 3,600 Fahr. to fuse it, has 

 been reduced to the molten condition. 



Zinc, as I have said, is a fuel far too expensi vre to per- 

 mit of the electric light produced by its combustion being 

 used for the common purposes of life, and you will readily 

 perceive that the human muscles, or even the muscles of 

 a horse, would be more expensive still. Here, however, 

 we can employ the force of burning coal to turn our ma- 

 chine, and it is this employment of our cheapest fuel, 

 rendered possible by Faraday's discovery, which opens 

 out to us the prospect of being able to apply the electric 

 light to public use. 



In 1866 a great step in the intensification of induced 

 currents, and the consequent augmentation of the magneto- 

 electric light, was taken by Mr. Henry Wilde. It fell to 

 my lot to report upon them to the Royal Society, but be- 

 fore doing so I took the trouble of going to Manchester 

 to witness Mr. Wilde's experiments. He operated in this 

 way: starting from a small machine like that worked in 

 your presence a moment ago, he employed its current to 

 excite an electro-magnet of a peculiar shape, between 

 whose poles rotated a Siemens armature; * from this ar- 



1 Page and Moigtio had previously shown that the magneto-electric current 

 could produce powerful electro-magnets. 



