Artificial Lighting 



159 



the work of Dr. John Clayton (1739) and Thomas Shirley 

 (1759). Murdock introduced the use of gas for lighting into 

 several factories ; and by 

 1805 Manchester was light- 

 ing its cotton mills with coal 

 gas. Progress in its use 

 was fairly rapid. London 

 shortly after 1810 made it 

 the chief illuminant ; Paris 

 began its use in 1820 ; Bal- 

 timore in 1821 ; Boston 

 in 1822; and New York 

 City, which did not intro- 

 duce it before 1823, had it in common use by 1827. 



60. Modern lighting. The chief means of illumination 

 to-day are kerosene oil, electricity, and artificial gas, which may 



1896 1898 1900 1902 1904 1906 1908 1910 1912 1914 1916 



FIG. 44 A. Graphic illustration of 

 the decrease of cost of electric lighting 

 in twenty years. 



FIG. 44 B. The cost of electric current for lighting has decreased greatly 

 since the year 1880. The relative candle power purchased by the same money 

 in given years is shown graphically. 



