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SCIENCE PROGRESS 



THE PROGRESS OF THE ELECTRIC 



LIGHT 



By MAURICE SOLOMON, A.C.G.I., M.I.E.E. 



Electric lamps have been improved so materially during the 

 past few years that to-day the position of the electric light is 

 radically different from that of ten or even five years ago. At 

 that time the methods of lighting by electricity appeared to 

 be in a stable, if not in a stagnant, state. The carbon filament 

 lamp, the original glow-lamp of Edison and Swan, had been 

 brought to perfection so far as that desirable condition is ever 

 likely to be reached in the case of an article manufactured 

 in many millions annually : for interior lighting of all but the 

 largest rooms it represented the best lamp that the electrical 

 engineer could produce to compete with the high-efficiency 

 mantle at the disposal of the gas engineer. In many respects 

 doubtless a most efficient competitor, it was heavily handi- 

 capped by the high running cost. The best that could be hoped 

 for with any confidence was a steady advancement in its use 

 as more and more persons found themselves in a position to 

 indulge in what was undoubtedly a luxury in artificial lighting ; 

 any great advance such as would be caused by the opening up 

 of new fields could only be the result of some radical improve- 

 ment which would at one stroke bring electric lighting into 

 effective competition with gas on the score of cost. That 

 improvement came with the invention of the metallic filament 

 lamp and when once the initial difficulties of commercial 

 manufacture were overcome interior electric lighting was given 

 a fresh start. Almost at the same moment the production of 

 satisfactory flame arc lamp carbons enabled electricians to make 

 a great stride forward in the field of exterior lighting and the 

 lighting of large interiors. 



Without wishing in any way to suggest that finality has 

 been reached in the case either of the metallic filament lamp or 



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