THE ELKGTRIG LIGHT. 665 



by Faraday, being always accompanied, in a closed con- 

 ductor, by the production of an "induced" electric cur- 

 rent which, as long as the ends of the coil remained 

 separate, had no circuit through which it could pass. The 

 current here evoked subsides immediately as heat; this 

 heat being the exact equivalent of the excess of effort just 

 referred to as over and above that necessary to overcome 

 the simple weight of the coil. When the coil is liberated 

 it falls back to the table, and when its ends are united it 

 encounters a resistance over and above that of the air. It 



feuerates an electric current opposed in direction to the 

 rst, and reaches the table with a diminished shock. The 

 amount of the diminution is accurately represented by the 

 warmth which the momentary current develops in the 

 coil. Various devices were employed to exalt these induced 

 currents, among which the instruments of Pixii, Clarke, 

 and Saxton were long conspicuous. Faraday, indeed, fore- 

 saw that such attempts were sure to be made; but he 

 chose to leave them in the hands of the mechanician, 

 while he himself pursued the deeper study of facts and 

 principles. " I have rather/' he writes in 1831, " been 

 desirous of discovering new facts and new relations 

 dependent on magneto-electric induction, than of exalting 

 the force of those already obtained; being assured that the 

 latter would find their full development hereafter." 



For more than twenty years magneto-electricity had 

 subserved its first and noblest purpose of augmenting our 

 knowledge of the powers of nature. It had been dis- 

 covered and applied to intellectual ends, its application to 

 practical ends being still unrealized. The Drummond 

 light had raised thoughts and hopes of vast improvements 

 in public illumination. Many inventors tried to obtain it 

 cheaply; and in 1853 an attempt was made to organize a 

 company in Paris for the purpose of procuring, through 

 the decomposition of water by a powerful magneto-electric 

 machine constructed by M. Nollet, the oxygen and 

 hydrogen necessary for the lime light. The experiment 

 failed, but the apparatus by which it was attempted 

 suggested to Mr. Holmes other and more hopeful applica- 

 tions. Abandoning the attempt to produce the lime 

 light, with persevering skill Holmes continued to improve 

 the apparatus and to augment its power, until it was finally 

 able to yield a magneto-electric light comparable to that of 



