Submarine telegraphs

Map showing the telegraph routes from England for uniting Europe with India.By the 1890s submarine telegraphy was indispensable to imperial communications. Without it the telegraph would have been useless as a means of imperial administration. Most of the traffic carried by telegraphs, whether over land or under water, assisted private business transactions; Paul Julius Reuter started his telegraphic news service in 1851 as a means of relaying stock and share prices.

However, overland telegraphy proved its undeniable worth as an instrument of imperial control during the Indian Mutiny of 1857. In the wake of the Indian Mutiny, the British Government had underwritten the construction of a telegraph cable from Suez to Karachi. This, along with the other long distance telegraphic cables shown in the map here, failed to transmit any messages.

The art collector John Watkins Brett (1805-63), who provided much of the capital for several long distance telegraphic cables, had auctioned some of his art collection to pay for the first oceanic telegraph under the Straits of Dover. In the years before the 1860s, when undersea telegraphic technology was very far from proven, this infant industry would not have survived without dreamers such as Brett.              
 
Chart showing the intended telegraphic communications between England & America. 1856.Sir Charles Tiltson Bright (1832-88) was the engineer responsible for the laying of the first Atlantic telegraph in 1858, for which Brett had provided much of the capital. It ran between Valentia (on the west coast of Ireland) and Newfoundland.

Bright was awarded a knighthood after he had overcome the very considerable engineering problems in laying the cable. As Bright’s exhaustive study of the technology of telegraphy makes clear, submarine telegraphy was a very capital-intensive industry. Britain had a virtual monopoly of technology, capital and access to the necessary raw material: an ‘imperial-technological-commercial complex’, as the historian of science Patricia Fara has put it. This material was gutta percha, which was almost as ubiquitous in Victorian industrial and domestic contexts as synthetic plastics are in ours.

In 1848 Michael Faraday had published his observations on the insulating properties of this material. Gutta percha is derived from the latex of gutta trees, found primarily in the Malay peninsula. As Bright shows, gutta percha can be shaped when hot but stays firm but flexible as it cools. In order to retain its properties of insulation and durability, it needs to be stored in water. Fortunately, it does not absorb much water. It was thus the ideal material for insulating long stretches of undersea cable. So useful was gutta percha for telegraphy that, by the end of the 19th century, supplies had been almost denuded and there was a worldwide shortage.

Submarine telegraphs by Charles Bright.However, submarine telegraphy posed not just an engineering problem, but also a scientific one. Even if the technical problem of laying submarine cables were overcome, the weakening of electric signals through leakages in insulation often resulted in garbled messages or no messages at all.

Unusually for most 19th century industry, the relationship between physics and telegraphy was very close. The physicist William Thomson, Baron Kelvin (1824-1907) devised measuring machines which were sensitive enough to detect even very weak currents over a long distance, and which made the Atlantic cable by 1866 viable as a means of transmitting messages.

Although the King’s physicist James Clerk Maxwell (1831-79) was not directly involved in telegraphy, his research was influenced by the problems with which Thomson had grappled. Without the continued support of physicists submarine telegraphy would not have been possible. In turn, telegraphy stimulated the invention of sensitive instruments which became laboratory equipment. As Patricia Fara goes on to say, contemporaries conceived of the telegraph system in scientific metaphors:

Victorian imperialists enthused that the telegraphic network resembled a giant nervous system that connected the brain of London to remote regions like the sensitive tips of a starfish’s limbs feeling out sources of food.
 

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