RCA Victor “Television” sales display binder, 1948. A standing flipbook with 31 pages advertising television receivers made by RCA. “RCA Victor / Television” on cover; “Tumble Top Binder / 54 QC 73 / Pat. 2,258,282 / The Barrett Bindery Co. Chicago” printed inside the back cover. Patent was issued 7 October 1941 to Elmer W. Ericson, assigned to the Barrett Bindery Co. “Form 1A 18052" on first page. This book was used in Ferrara Radio, a retail and service shop founded by Salvatore “Thomas” Ferrara (1900-1970) in 1931. Located in Yonkers, NY, Ferrara added television sales and service to his business in the late 1940s.
This GE wire recorder is a licensed copy of the Armour model 50 recorder designed and made for the U.S. military during World War II. Based on the work of Marvin Camras, Armour fabricated wire recorders at a small, specially-built plant until 1944. The demand for increased production of recorders led GE to begin production of the model 51.
The Armed Forces Radio Service used a variety of recording devices, including wire recorders, to bring programming to troops stationed around the world. This wire recorder used four vacuum tubes and ran on alternating current.
These recording discs were made for the Brush Company “Mail-A-Voice” dictating machine. This set of 62 discs includes several slightly different types, the most significant difference being that some are paper and some are plastic. All are flexible and coated with a magnetizable powder. The Mail-A-Voice was designed by German immigrant Semi J. Begun who also used the device for personal correspondence. Several of the discs in the set are audio letters from Begun to his mother.
This “Red Head” recording-playback head was designed by Brush Company around 1950 for sale to tape recorder manufacturers. Inside the housing is a small, specially-shaped electromagnet designed to produce a focused magnetic field. When recording, a current fed into the head varied according to the strength of the input signal and that variation was captured by the recording tape. For playback, the magnetic field on the tape generated a signal in the head as it passed close. The closer the playback signal matched the input signal, the more accurate the recorded sound.
As knowledge of materials and experience making electric lamps grew in the early 20th century, more efficient light sources began to reach the market. In 1932 a collaboration of General Electric Company of England (GEC), Philips in the Netherlands, and Osram in Germany introduced a discharge lamp that used low-pressure sodium vapor. The key to a workable sodium lamp lay in a special glass (called borate glass) that could withstand the very corrosive nature of sodium. Arthur Compton in the U.S. described such a glass in 1926. But it took five more years to learn how to actually produce it so that a lamp could be made.
Discharge lamps make light by passing an electrical current through a gas, in this case sodium vapor. The current energizes the gas which then emits light. In this lamp, the sodium is contained by the bulb, which is lined with the borate glass. The lamp in turn is mounted inside a larger, double-walled glass jacket (part of the light fixture, not shown) to keep the temperature around the lamp stable during operation. Sodium light is a stark yellow suitable only for use in applications like street lighting, but the energy efficiency is very high. Early models gave 40 lumens per watt (lpw), a figure that reached about 100 lpw by 1960. Today's low-pressure sodium lamps give close to 200 lpw, the most energy efficient light source commercially available.
This lamp was made for street-lighting use by (U.S.) General Electric around 1940.
Lamp characteristics: Plastic, four-post base. Re-coiled tungsten electrodes mounted inside metal shields. The small brown cylinder mounted near the stem press is a starting resistance. Six asbestos insulator rings mount on the lamp's neck and are secured by the brass collar. (The rings have been removed and stored while the lamp is on display and are not in this picture.) Tipless, T-shaped envelope with about 70% of the inner wall coated by condensed sodium.
Production Fluorescent Miniature Christmas-tree lamp, Coral color, 4w. Circa 1946. Brass candelabra screw-base with glass insulator, plastic skirt. Two electrodes inside lamp, gas fill (argon?). Tipless G-shape envelope with phosphor coating on inner bulb-wall. Printed on skirt: "Sylvania Fluorescent 04 4W-120AC Coral [Sylvania Logo]". Unit operates via coronal discharge.