On the practical bearing of the theory of electricity in submarine telegraphy, the electrical difficulties in long circuits, and the conditions requisite in a cable to insure rapid and certain communication
S.Alfred Varley. "On the practical bearing of the theory of electricity in submarine telegraphy, the electrical difficulties in long circuits, and the conditions requisite in a cable to insure rapid and certain communication." Journal of the Franklin Institute 68.4 (1859) 259-267