THE ELECTRIC LIGHT. 447 



raise to vivid incandescence a refractory metal like 

 iridium or one of its alloys. Instead of being tapped 

 at one point, our main may be tapped at one hundred 

 points. The current will divide in strict accordance 

 with law, its power to produce light being solely limited 

 by its strength. The process of division closely re- 

 sembles the circulation of the blood ; the electric main 

 carrying the outgoing current representing a grent 

 artery, the water-pipes carrying the return current re- 

 presenting a great vein, while the intermediate branches 

 represent the various vessels by which the blood is dis- 

 tributed through the system. This, if I understand 

 aright, is Mr. Edison's proposed mode of illumination. 

 The electric force is at hand. Metals sufficiently re- 

 fractory to bear being raised to vivid incandescence are 

 also at hand. The principles which regulate the 

 division of the current and the development of its light 

 and heat are perfectly well known. There is no room 

 for a ' discovery,' in the scientific sense of the term, 

 but there is ample room for the exercise of that me- 

 chanical ingenuity which has given us the sewing 

 machine and so many other useful inventions. Know- 

 ing something of the intricacy of the practical problem, 

 I should certainly prefer seeing it in Mr. Edison's hands 

 to having it in mine. 1 



It is sometimes stated as a recommendation to the 

 electric light, that it is light without heat ; but to dis- 

 prove this, it is only necessary to point to the experi- 

 ments of Davy, which show that the heat of the voltaic 

 arc transcends that of any other terrestrial source. The 

 emission from the carbon points is capable of accurate 

 analysis. To simplify the subject, we will take the 



1 More than thirty years ago the radiation from incandescent 

 platinum was admirably investigated by Dr. Draper of New York. 



