Submarine telegraph switch marked: "Muirhead & Co. Ltd / No. 38986". This switch was used on a submarine cable when the cable was worked simplex to allow switching between transmit and receive condition on the cable. As it switched between transmit and receive, it would ground the cable momentarily, thereby freeing the cable of any charge which could damage the receiving system. Hard rubber base and handle with four terminals and switch arm made of brass. Terminals marked: R, E, L and K. The switch is part of a submarine telegraph testing system, mounted on a black-painted base with another switch and a double key.
A double pole-double throw switch with two levers connected with an insulated block. This block is actuated by a brass handle, to switch between two sets of contacts. Six terminals across the back edge of the base, two of which are wired together, three others have separate cloth-insulated copper leads. The base is hard rubber. The switch is part of a submarine telegraph testing system mounted on a black-painted wooden base with another switch and a double key. Maker unknown, possibly Muirhead.
Benjamin 6-lamp cluster adapter. brass medium-screw base with porcelain insulator, six brass candelabra screw sockets with plastic insulator, porcelain housing, stamped on top: “Benjamin-Pat.-May-17-1904”
Benjamin 4-lamp cluster adapter. brass medium-screw base with porcelain insulator, four brass candelabra screw sockets with plastic insulator, porcelain housing, stamped on top: “Benjamin-Pat.-May-17-1904”
Early radio inventors used a variety of methods to detect radio waves. Those early detectors tended to be slow and cumbersome in operation and that limited transmission speed. In 1906, Lee de Forest built on the work of Thomas Edison and John Ambrose Fleming and invented an electron tube he called an “Audion.” His tube contained three internal elements: a filament, an electrode and a control grid. Today we call tubes of this type “triodes.” In 1907 De Forest received U.S. Patent #841,387 for his invention, one of the most important in the history of radio.