from the GNU version of the Collaborative International Dictionary of English
- n. A device utilized in the making of a loud-speaking telephone, depending on the fact that the friction between a metallic point and a moving cylinder of moistened chalk, or a moving slip of paper, on which it rests is diminished by the passage of a current between the point and the moving surface.
from The Century Dictionary and Cyclopedia
- n. A form of telegraph-or telephone-receiver, invented by Edison, depending for its action on the variation of the friction between two conductors in relative motion, when a current of electricity is passed from one to the other across the surface of contact.
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Probably the first instance in which the electric current was directly employed to vary the amount of friction between two rubbing surfaces was exemplified in Edison's electro-motograph, in which the variations in the strength of a telephonic current caused corresponding variations in friction between a revolving cylinder of moistened chalk and the free end of an adjustable contact arm whose opposite extremity was attached to the diaphragm of the receiving telephone.
A year or two later the motograph cropped up again in Edison's work in a curious manner.
In his researches to determine the nature of the motograph phenomena, and to open up other sources of electrical current generation, Edison has worked out a very ingenious and somewhat perplexing piece of apparatus known as the ` ` chalk battery. ''
He made a similar agreement for the same sum offered him for the patent of the electro-motograph.
In his researches to determine the nature of the motograph phenomena, and to open up other sources of electrical current generation, Edison has worked out a very ingenious and somewhat perplexing piece of apparatus known as the "chalk battery."
This "electro - motograph" receiver was, however, given up, and a combination of the Edison transmitter and the Bell receiver came into use.
The record made in New York on the Edison phonograph was repeated into an Edison carbon transmitter, sent over one hundred and three miles of circuit, including six miles of underground cable; received by an Edison motograph; repeated by that on to a phonograph; transferred from the phonograph to an Edison carbon transmitter, and by that delivered to the Edison motograph receiver in the enthusiastic lecture-hall, where every one could hear each sound and syllable distinctly.