NO. 2 



HISTORY OF ELECTRIC LIGHT SCHROEDER 



6i 



for use on series circuits. These were called the Bernstein, Heisler, 

 Large Edison, Municipal Bernstein, Municipal Edison, Thomson- 

 Houston (alternating circuit) and Thomson-Houston (arc circuit). 

 Some of these bases disappeared from use and in 1900 the proportion 

 in the United States was about 70 per cent Edison, 15 per cent West- 



i4h :£r 



Bernstein. 



Heisler. 



Thomson-Houston 

 (alternating current). 



Municipal Bernstein. 



Thomson-Houston Municipal Edison, 



(arc circuit). 



Various Series Bases in Use, 1892. 



The above six bases have been superseded by the " Large Edison," 

 now called the Mogul Screw base. 



inghouse, 10 per cent Thomson-Houston and 5 per cent for all the 

 others remaining. A campaign was started to standardize the Edison 

 base, adapters being sold at cost for the Westinghouse and Thomson- 

 Houston sockets so that Edison base lamps could be used. In a few 

 years the desired results were obtained so that now there are no other 

 sockets in the United States but the Edison screw type for standard 



