Bell speaking telephone receiver/ transmitter
Date: circa 1877
Inventory Number: 8007
Classification: Telephone
Subject:
Owner: Jefferson Physical Laboratory, Harvard University (founded 1884)
Inventor: Alexander Graham Bell ? (1847 - 1922)
Cultural Region:
Place of Origin:
Dimensions:
16.9 × 7 × 7 cm (6 5/8 × 2 3/4 × 2 3/4 in.)
Description:
A Bell magneto telephone receiver/transmitter of wood, of a shape known as a "butterstamp" type.
The handle is a straight-sided turned wood cylinder, pierced by two holes on the end, one of which has a bit of electrical wire attached to it. Two metal binding posts, with screw-tops are attached to the end face of the handle, along with a screw mounted in the center. At the other end, the cylindrical handle curves and widens to connect smoothly with a wider, turned wood cylinder containing the receiver/transmitter. The receiver/transmitter has a wooden faceplate, secured with three screws, and a convex, bowl-shaped speaker/earpiece pierced by a round hole at the bottom of the bowl. From the inside of the receiver/transmitter the speaker/earpiece hole is loosely covered by a piece of dark material.
This type of phone used an "earth" return circuit, which depended on the geoelectrical properties of the Earth's crust as a conductor to complete the telephone circuit.
The handle is a straight-sided turned wood cylinder, pierced by two holes on the end, one of which has a bit of electrical wire attached to it. Two metal binding posts, with screw-tops are attached to the end face of the handle, along with a screw mounted in the center. At the other end, the cylindrical handle curves and widens to connect smoothly with a wider, turned wood cylinder containing the receiver/transmitter. The receiver/transmitter has a wooden faceplate, secured with three screws, and a convex, bowl-shaped speaker/earpiece pierced by a round hole at the bottom of the bowl. From the inside of the receiver/transmitter the speaker/earpiece hole is loosely covered by a piece of dark material.
This type of phone used an "earth" return circuit, which depended on the geoelectrical properties of the Earth's crust as a conductor to complete the telephone circuit.
Signedunsigned
FunctionConversion of sound into electrical signals for transmission over a distance and conversion of signals into sound for output
Curatorial RemarksItems 8006 and 8007 are very similar.
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. 23-24.