Solar cells come in many shapes and sizes, and are manufactured with a variety of materials. Hoffman Electronics made cells for satellites in the late 1950s but company president H. Leslie Hoffman believed the sun could power other products. This type 200A quarter-round cell is mounted in a plastic housing and was sold through radio supply houses and catalogs. Hoffman manufactured a line of solar-powered radios that used quarter-round cells of this type.
Western Electric desk telephone on extender - "5-51" printed on transmitter module. Unit includes a desk mount, scissors-type extender, transmitter unit with lever switch, and single earphone. Presumably for business use.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use.
American Greetings solar powered birthday card. Depicts a monkey surfing - when exposed to light, a photocell powers a small motor to make the monkey's tail wag.
A telegraph practice set used as an introduction to landline telegraphy technology and Morse code. Includes two key-sounder combination sets and a roll of bare copper wire. Also a pad of blank telegram sheets and a reproduction instruction manual. The cover appears original but the pages are blank. Penciled note: "Toy Mfgs. of U.S.A. #82"; printed on package: “A. C. Gilbert”, “3502 Teleset”.
A keyless socket for a medium screw-based lamp, brass spring shell, mounted on a wooden stand. The coil serves as an anti-theft device. A lamp can be inserted into the socket normally, but if the spring lever is not pressed, the lamp will break when removed. This deters the theft of light bulbs in an era when they were quite expensive. Yellow tag on unit reads: "No. 5 Dec. 15.91 / Pieper Socket / From Steam Ship / La Borjamin [?] / [illegible] / 5. 12.15.91 / Pieper Socket / Wilson S. [??]"
A Geissler tube with outer envelope containing a red liquid, and internal glass structure consisting of (in series) a chamber, a spiral with bend, and another chamber. A metal electrode is inserted at both ends. Almost all air has been evacuated from the internal structure. When an electrical charge is passed between the electrodes, the remaining air in the tube glows, and the light is colored by the liquid. Geissler tubes were used as demonstration pieces and occasionally as lamps.
Dating stamp from Morse's Electromagnetic Telegraph Company's Baltimore office. A ca. 1915 label reads:: "E. Mag. Telegraph Company, Baltimore. Supposed to have been used in the business of the Morse telegraph line between Washington and Baltimore."