The Transatlantic Telegraph Cable was a breakthrough for world communication. A simple 5mm copper wire core coated in a well-calculated protective casing supported the first intercontinental communications revolution and allowed Morse code messages to cross the great Atlantic Ocean in seconds.
During the 1840’s and 50’s, a series of important engineering and scientific experiments were being undertaken to solve the challenge of achieving a global communication network and ‘link new worlds to old’. Samuel Morse and Alfred Vail’s famous ‘Morse Code’ was already widely used in electric telegraphy across many countries including Great Britain and America. But to link the two nations together a connection had to be made across the Atlantic Ocean; and a cable had to be designed to withstand corrosion, water pressure and accidental damage.
Michael Faraday was one of the first to recognise the beneficial properties of gutta-percha as an electrical insulator when Dr. William Montgomerie first brought the plant back to England from South-East Asia. This curious tropical tree hosted a resin with the perfect properties to protect underwater cables and would transform underwater cable engineering forever.
Charles Vincent Walker was thought to have linked the first gutta-percha cable from a ship to a land based railway station in 1849. The Brett Brothers soon followed this inspirational step forward and established the Submarine Telegraph Co and a submarine telegraph cable link across the English Channel to connect Dover and Calais.
Continued success that followed this, in many other attempts and within many other countries, inspired Cyrus Field to step forward. He collaborated with Samuel Morse, and the Brett Brothers completing telegraph lines between Cape Ray and Cape Brenton in 1855 and between Newfoundland and St John’s the following year. Afterwards, he turned his ambitions to a connection between Newfoundland and Ireland – a project that would require 2,500 miles of cable and an army of investors. He formed the Atlantic Telegraph Co on the 6th November 1856 in London realising the UK was to be a logical source of funding for the challenge. John Pender a cotton merchant and one of these investors became the director of the Atlantic Telegraph Company.
The People Behind The Manufacturing
The years to come would see many problems arise with the delicate cable engineering attempts, and after each technical failure, the materials used in its construction were openly debated. Great discussions were held amongst institutions and engineering societies about the preferences of india-rubber over gutta-percha, several of which we have accounts of in The Engineer:
"In 1850 we began to insulate the conductors of submarine cables with india-rubber. Gutta-percha entirely superseded the use of india-rubber. The man would have been voted a lunatic who dared to recommend india-rubber in preference to gutta-percha; and yet within the last two or three months experiments have been going on which it is said show conclusively that india-rubber is far superior to gutta-percha for coating submarine conductors...." - From 'Submarine Telegraphy' An Anonymous Letter to The Editor of Engineer Journal 1859/03/18, p 184
"Mr Ransome stated that he had frequently found that gutta-percha became so rotten in the course of two or three years that it could be crumbled away between the fingers. It could however be restored to its original condition by immersing it in hot water." - From an ordinary meeting of The Manchester Literary and Philosophical Society of Engineer Journal 1859/04/08, p 247.
James Horsfall was to become a significant pioneer in the manufacture of a wire that had twice the tensile strength of any previously known. His methods were highly praised and he was to receive the entire wire order for the Atlantic Telegraph Cable:
“The cable is capable of bearing a strain of 8 tons without breaking yet it coils into the tanks as easily as silken rope. The wires are composed of homogeneous iron of unusually uniform quality – with credit to Mr James Horsfall – he found it absolutely necessary to manufacture his own iron, roll it, draw it and anneal it to achieve such uniform. The wires were then covered with five strands of Manilla hemp saturated with a compound of pitch, oil, tar and a little india-rubber, resulting cable being very pliable and yet not “springy” like the qualities known of submarine cables.” From 'The Atlantic Cable' Editorial of Engineer Journal 1865/06/02, p 346.
Read about the companies involved:
A Signal Breakthrough
William Thompson and Mr Cromwell Fleetwood Varley developed a variety of testing instruments to improve the cable signalling techniques. Thompson ensured that after many failures during months of cable-laying attempts and weak signals, it was eventually laid properly, with a signal stronger than ever before. His new mirror galvanometer, patented in 1858, was extremely sensitive and hence able to respond to very small signals.
Perhaps the most famous of all messages sent hereafter were those between Queen Victoria and President James Buchanan of America and Queen Victoria in her first sentence remarked: “The Queen desires to congratulate the President upon the successful completion of this great international work, in which the Queen has taken the greatest interest”.
The development and dedication of the transatlantic telegraph cable was indeed of enormous international importance and a major breakthrough in telecommunications. Although there were many problems encountered and many failed cable-laying expeditions, the idea of global communications first dreamed of decades ago finally became achievable.