The first recorded uses of electric cables were for exploding mines and for telegraphy. The mines were exploded in the Baltic by the Russian Schilling in 1812, and the first telegraphed messages were transmitted by Francis Ronalds in 1816 through a copper wire laid underground. Insulated cables date from 1838, the original insulating materials being tarred rubber and pitch-covered yarn.
Beginning with work by Ampère in 1820, various systems of telegraphy were invented and tried out before Cooke and Wheatstone installed the first British electric telegraph to be put into commercial use in 1837; this was on a stretch of the London and North-Western Railway between Euston and Chalk Farm (Fig. 36). In 1843 a similar installation was put into service between Paddington Station and Slough, on the Great Western Railway. These systems employed copper conductors and required five wires supported in grooved wooden blocks. Almost simultaneously Henry and Morse were undertaking similar projects in the United States.
A short length of the first British commercial telegraph which was laid by Cooke and Wheatstone in 1837. It linked Euston Station and Camden Town, and consisted of five copper wires supported in grooved wooden blocks.
In 1846 the first British commercial telegraph company was formed, and after twenty years had elapsed, three of these companies owned between them no less than 16,000 miles of line.