Cabling the Channel

The recent construction of the channel tunnel has been heralded as one of the great engineering feats of this century. In 1851 an engineering event took place that connected England and France together in a different, but no less important, way.

Towards the middle of the 19th century the electric telegraph was mainly responsible for bringing together communities that had previously existed in isolation. The connecting of these communities was bringing about a revolutionary change in their economic and social relations.

By 1840 a condition had developed whereby a telegraph line connected London to Dover and another line connected Calais to Paris. This situation, of no direct connection between the two great cities, was soon seen as being unacceptable. It spurred the British physicist Charles Wheatstone to put forward proposals for a submarine cable to be laid across the English Channel.

The main obstacle to the project's progress was the discovery that rubber, thought to be suitable for protection of the cable, was found to break down when submerged in salt water for any length of time.

By the mid-1840's the properties of a material called 'gutta percha', a material resembling rubber in its chemical composition, was recognized by Michael Faraday. However, it differed from rubber in being tough and inelastic at ordinary temperatures and soft and plastic when placed in hot water. It was an excellent material for submarine cables and was to be used for the purpose until its replacement by Polythene in the 1950s.

There was also the problem of applying it to a copper conductor. By the Spring of 1850 most of the difficulties seemed to have been overcome, and a order was placed, with the Gutta Percha Company, for 25 miles of cable. The specification was a single copper wire of No 14 Birmingham Wire Gauge, with a covering of 'gutta purcha' to a diameter of half inch. There was no outer armouring or covering of the cable and it came in 100 yards lengths.

Two brothers, Jacob and John Watkins Brett, first had ideas to lay a submarine cable across the Atlantic Ocean. The little interest shown in such a mammoth task, however, caused them to turn to the more practical idea of laying a cable across the Straits of Dover. Connecting, for the first time, a telegraph cable link between two countries seperated by water.

On the 28 August 1850 the steam tug Goliah laid the first cable.
The shore on the English side terminated in a 'horse box', housing the instruments, at Dover. On the French side the shore section of the cable was laid from Cap Gris Nez.

As the cable was laid out from the Goliah, lead weights were attached at frequent intervals to ensure its sinking to the sea bed.
Joints were made at the shore ends and messages exchanged, by way of a Cooke and Wheatstone needle telegraph. One of the messages was sent to Prince Louse Napoleon Bonaparte who had shown much interest in the whole enterprise.

When, on the following day, excited attempts were again made to contact France, the operators were met with silence.The cable was dead. On investigation it was found that a puzzled French fisherman had fouled up the cable with his anchor. He considered it to be some strange form of sea-weed and so chopped of a length to take home to show his family and friends.

Although short lived, the 1850 cable had shown the way. On the 25 September 1851 a much improved cable, by Thomas Cramton a railway engineer, was laid. By the 13 November the cable was open for regular traffic and remained in operation for many years, making it the first efficient submarine cable.