THE CONQUEST OF NATURE 



THE MERCURY- VAPOR LIGHT OF PETER COOPER HEWITT 



"On an evening in January, 1902, a great crowd 

 was attracted to the entrance of the Engineers' Club in 

 New York city. Over the doorway a narrow glass 

 tube gleamed with a strange blue-green light of such in- 

 tensity that print was easily readable across the street, 

 and yet so softly radiant that one could look directly 

 at it without the sensation of blinding discomfort which 

 accompanies nearly all brilliant artificial lights. The 

 hall within, where Mr. Hewitt was making the first 

 public announcement of his great discovery, was also 

 illuminated by the wonderful new tubes. The light 

 was different from anything ever seen before, grateful 

 to the eyes, much like daylight, only giving the face a 

 curious, pale-green, unearthly appearance. The cause 

 of this phenomenon was soon evident; the tubes were 

 seen to give forth all the rays except red, orange, 

 yellow, green, blue, violet, so that under its illumination 

 the room and the street without, the faces of the spec- 

 tators, the clothing of the women, lost all their shades 

 of red ; indeed, changing the face of the world to a pale 

 green-blue. 



"The extraordinary appearance of this lamp and its 

 profound significance as a scientific discovery at once 

 awakened a wide public interest, especially among 

 electricians who best understood its importance. Here 

 was an entirely new sort of electric light. The familiar 

 incandescent lamp, though the best of all methods of 

 illumination, is also the most expensive. Mr. Hewitt's 



[236] 



