THE CONQUEST OF NATURE 



palaces of the Shah of Persia and the King of Cambodia, 

 and a little later were introduced into the residence of 

 the savage King of Burma. In short, their use became 

 universal almost immediately. 



THE IMPROVED ARC LIGHT 



About the time that Jablochkoff's candles were 

 making such a sensation in Europe, Charles F. Brush, of 

 Cleveland, Ohio, invented an arc light in which the 

 carbons were set point to point, the distance being 

 maintained and the necessary feed produced auto- 

 matically in much the same manner as in the lamps 

 used at present. Other inventions soon followed, some 

 of the lamps being regulated by clockwork, some by 

 electricity and magnetism. 



The advantage of this type of arc lamp over the candle 

 type an advantage that led to its general adoption- 

 was largely that of efficiency, a far greater amount of 

 light being obtainable from the same expenditure of 

 power by the point-to-point type of lamp. 



In this lamp it is necessary that the points of carbon 

 shall come in contact when the current is off, but be 

 drawn apart a moment after the current is turned on, 

 and remain at this fixed distance. To accomplish this, 

 the lower carbon is usually made stationary, the feeding 

 being regulated by the position of the upper carbon. 

 In the usual type of modern lamp the passage of the 

 current causes the points to separate the required dis- 

 tance through the action of an electromagnet the coils 

 of which are traversed by the current. A clutch holds 



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