NO. 2 



HISTORY OF ELECTRIC LIGHT SCHROEDER 



51 



a thumb screw which forced the socket terminals tight against the 

 neck of the bulb. 



This crude arrangement was changed in the latter part of 1880 to 

 a screw shell and a ring for the base terminals, wood being used for 



Original Socket i'or Incandi£scent Lamps, i{ 



Wire Terminal Base Lamp, 1880. 



This crude form of lamp base fitted the original form of lamp 

 socket pictured above. This lamp is in the exhibit of Edison lamps 

 in the Smithsonian Institution. 



insulation. The socket was correspondingly changed. This was a 

 very bulky affair, so the base was changed to a cone-shaped ring and 

 a screw shell for terminals. Wood was used for insulation, which 

 a short time after was changed to plaster of Paris as this was also 

 used to fasten the base to the bulb. It was soon found that the tension 

 created between the two terminals of the base when the lamp was 



