Berliner steel-ball sender
Date: 1877-1878
Inventory Number: 8050
Classification: Telephone
Subject:
Maker: Emile Berliner (1851 - 1929)
Cultural Region:
Place of Origin:
Dimensions:
4.4 × 11.8 × 10.6 cm (1 3/4 × 4 5/8 × 4 3/16 in.)
Material:
DescriptionPart of a telephone sender, or variable resistance transmitter. The transmitter is housed in a square wooden case, with two metal binding posts with knurled-edge thumb screws on one side. A black, dish-shaped mouthpiece is mounted on the front of the case. The box lid, secured by brass hinges, can be opened for access to the inside. The front of the case is warped and the latch is missing. A rounded opening on the back of the case may be designed to permit wall mounting. A rounded opening on the front of the case may have held the latch.
Inside, a flat disk of mica is held in place by three brass brackets. In the center of the disk, hanging inside the box below the exterior mouthpiece, is a weighted pendulum whose movement regulates the strength of the current passing through a circuit connected to the binding posts. The binding posts are connected to the pendulum assembly by a pair of insulated electrical wires.
The rights to Emile Berliner's patent for this device, which he applied for in 1877, were acquired by the Bell Company in 1878. Berliner went on to patent the first flat-disk phonograph, the gramophone, in 1887.
Inside, a flat disk of mica is held in place by three brass brackets. In the center of the disk, hanging inside the box below the exterior mouthpiece, is a weighted pendulum whose movement regulates the strength of the current passing through a circuit connected to the binding posts. The binding posts are connected to the pendulum assembly by a pair of insulated electrical wires.
The rights to Emile Berliner's patent for this device, which he applied for in 1877, were acquired by the Bell Company in 1878. Berliner went on to patent the first flat-disk phonograph, the gramophone, in 1887.
Signedunsigned
FunctionConversion of electrical signals into sound for output by telephone
ProvenanceJefferson Laboratory, Physics Department, Harvard University
Published ReferencesThis instrument is described in:
Thomas G. Hedberg, "Catalogue: Telephones, Phonographs and Related Instruments in The Collection of Historical Scientific Instruments at Harvard University." William Andrewes, Project Director (unpublished manuscript, President and Fellows of Harvard College and Thomas G. Hedberg, 1989. Fifth Draft), pp. 31-32.
see also:
John Brooks, Telephone: The First Hundred Years, 2nd ed. (New York: Harper & Row, 1976), pp.102-103.