THE ELECTRIC LIGHT. 163 



CHAPTER XIX. 



THE ELECTRIC LIGHT. 



THE four very bright lights which can be produced by 

 artificial means are, as Lawrence enumerated them in his 

 explanations to John (if we leave out the Argand burner, 

 which is, after all, only the form of a burner, and not a 

 special mode of producing light), the Bude Light, the 

 Magnesium Light, the Oxyhydrogen Light, and the Elec- 

 tric Light. The last named the Electric Light is in 

 some respects the most remarkable of all. 



The electric light is like the others which have been de- 

 scribed in this respect, namely, that it acts on the general 

 principle of raising solid particles to an intense degree of 

 incandescence by means of extreme heat, while it differs 

 from them all in the manner in which the heat is pro- 

 duced. In the other three the heat is produced directly 

 by the process of combustion, which, as we have already 

 seen, is another name for the force which is developed by 

 the combination of the combustible chiefly hydrogen 

 with oxygen. In this, on the other hand, the heat is pro- 

 duced by a current of electricity, though it is a remarka- 

 ble instance of the analogy which runs through the opera- 

 tions of nature, that the current of electricity which devel- 

 ops the heat is often produced by the combustion of zinc, 

 or, rather, by a process which is, in a chemical sense, essen- 

 tially combustion. The current, nevertheless, may be, and 

 now often is, produced in other ways. 



In whatever way the movement of electricity is occa- 

 sioned, it often produces luminous effects. The lightning 



