The Edison electric meter, like those of Sprague and Lane-Fox, was based upon the principle that when an electric current flows through an electrolyte, such as sulphate of copper or sulphate of zinc, the electrodes being plates of copper or zinc, metal is dissolved off one plate (the anode) and deposited on the other plate (the cathode).
Almost simultaneously with Berliner, Edison conceived the idea of using a variable resistance transmitter.
It has sometimes been claimed that Edison's proposed elevated plates anticipated the subsequent invention by Marconi of the aerial wire or antenna, but it is particularly to be noticed that Edison employed no spark gap or means for creating electrical high frequency oscillations in these wires.
Alexander Graham Bell in 1876 invented the speaking telephone, and Edison and Elisha Gray in the United States followed almost immediately with other telephonic inventions for electrically transmitting speech.
Now it had been previously shown by Edison that, when a current was made to pass through an arrangement like that just described, the friction between the paper and the spring was greatly diminished.
Edison in the United States, were engaged in struggling with the difficulties of producing a suitable carbon incandescence electric lamp. Edison constructed in 1879 a successful lamp of this type consisting of a vessel wholly of glass containing a carbon filament made by carbonizing paper or some other carbonizable material, the vessel being exhausted and the current led into the filament through platinum wires.
He was for five years a clerk in the office of an Irish land-agent, but came to London with his family in 1876, and in 1879 was, according to his own account in the preface to The Irrational Knot, in the offices of the Edison telephone company.
Both the Bell and the Edison Companies opened negotiations with the Post Office for the sale of their patents to the government, but without success.
The Edison Telephone Company of London was formed.
In 1879 and 1880, Edison in the United States, and Swan in conjunction with C. H.