CHAPTER XV 



ARTIFICIAL LIGHTING 



141. We seldom consider what life would be without our 

 wonderful methods of illumination which turn night into day, 

 and prolong the hours of work and pleasure. Yet it was not 

 until the nineteenth century that the marvelous change was 

 made from the short-lived candle to the more enduring oil lamp. 

 Before the coming of the lamp, even in large cities like Paris, 

 the only artificial light to guide the belated traveler at night 

 was the candle required to be kept burning in an occasional 

 window. 



With the invention of the kerosene lamp came more effi- 

 cient lighting of home and street, and with the advent of gas 

 and electricity came a light so effective that the hours of busi- 

 ness, manufacture, and pleasure could be extended far beyond 

 the setting of the sun. 



The production of light by candle, oil, and gas will be con- 

 sidered in the following paragraphs, while illumination by 

 electricity will be reserved for a later Chapter. 



142. The Candle. Candles were originally made by dipping 

 a wick into melting tallow, withdrawing it, allowing the ad- 

 hered tallow to harden, and repeating the dipping until a sat- 

 isfactory thickness was obtained. The more modern method 

 consists in pouring a fatty preparation into a mold, at the cen- 

 ter of which a wick has been placed. 



The wick, when lighted, burns for a brief interval with a 

 faint, uncertain light ; almost immediately, however, the inten- 



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