ELECTRIC LIGHTING. 311 



quadruplex. I worked on both over two years before I 

 overcame them." ' 



Other methods, as the Sawyer-Man system, and the 

 Brush system, need not at present detain us, as little is 

 certainly known respecting them. In the former it is said 

 that the light is obtained from an incandescent carbon 

 pencil, within a space containing nitrogen and no oxygen, 

 so that there is no combustion. In the latter the carbon 

 points are placed as in the ordinary electric lamp, but are 

 so suspended in the clasp of a regulator, that they burn 

 14 inches of carbon without adjustment, the carbons lasting 

 tight hours, and producing a flood of intense white light, 

 estimated as equivalent to 3,000 candles. 



I have little space to consider the cost of electric light- 

 ing, even if the question were one which could be suitably 

 dealt with in these pages. Opinions are very much divided 

 as to the relative cost of lighting by gas and by electricity ; 

 but the balance of opinion seem to be in favour of the 

 belief that in America and France certainly, and probably 

 in this country, where gas is cheap, electric lighting will on 

 the whole be as cheap as lighting by gas. It should be 

 noticed, in making a comparison between this country and 

 others in which coal is dearer, that the cheapness of coal here, 

 though favourable in the main to gas illumination, is also 

 favourable, though in less degree (relatively) to electric light- 

 ing. Machines for generating electricity can be worked 



point of giving up the telephone as a lost job ; but at the last moment, 

 he would see light." " Of all things that we have discovered, this is 

 about the simplest," continued Mr. Edison, "and the public will say 

 so when it is explained. We have got it pretty well advanced now, but 

 there are some few improvements I have in my mind. You see, it has 

 got to be so fixed that it cannot get out of order. Suppose when one 

 light only is employed it got out of order once a year, where two 

 were used it would get out of order twice a year, and where a thousand 

 were used you can see there would be much trouble in looking aft er 

 them. Therefore, when the light leaves the laboratory, I want it to be 

 in such a shape that it cannot get out of order at all, except of course 

 by some accident." * 



