The Hill Incandescent Lamp

An article in the May 1888 issue of Western Electrician¹ described the lighting apparatus of W. S. Hill, of Boston. Two of the figures showed their incandescent lamp. The picture to the far left shows a lamp and key socket. The picture to the near left shows the lamp and the method of attachment to the socket. The lamp terminals are of stout wire that are bent at right angles to form arms. Quoting from the article:

"As the lamp is inserted in the socket and turned partially round, these arms pass under wire springs, which hold the lamp securely in place, and also puts it in electrical connection with the circuit.. A pin in the brasscup of the lamp, and a groove in the socket insure the lamp entering the right place, and limit the turning motion so no injury can come either to the arms or springs."

Reference
1) "The Hill Electric Lighting Apparatus", Western Electrician, Vol 2, No 19, May 12, 1888, pg 231.