Excerpts from Books and Wikipedia
"However, the most significant development was the actual construction of submarine cables, first pioneered across the Channel in the early 1850s (Dover-Calais) 1851, Ramsgate-Ostend 1853), but increasingly over long distances. A north-Atlantic cable was proposed in the midid-1840s, and actually laid in 1857-8, but broke down due to inadequate insulation. The second attempt, with the celebrated Great Eastern--the largest ship in the world--as cable-layer, succeeded in 1865. There followed a burst of international cable-laying which, within five or six years, virtually girdled the globe. . . . By 1872 it was possible to telegraph from London to Tokyo and to Adelaide." [Hobsbawm: Capital, p. 59]