Submarine communication cable

The first submarine telegraph cable crossed the English Channel in 1850—and failed within hours. A fishing boat's anchor cut the unarmored wire. This ignominious start marked the beginning of two decades of failures, bankruptcies, and engineering breakthroughs that would eventually wire the world together.

The problem was not telegraphy itself; by 1850, land-based telegraph networks crisscrossed Britain and America. The problem was insulation. Electrical signals traveling through copper wire dissipate into surrounding conductors. On land, air provides sufficient insulation. Underwater, seawater is a conductor. Any submarine cable needed a waterproof insulating layer that could withstand the pressure, abrasion, and marine environment of the ocean floor.

The solution came from an unexpected material: gutta-percha, a latex sap from trees native to Southeast Asia. When heated, gutta-percha became pliable and could be molded around copper wire; when cooled, it hardened into a durable, waterproof sheath. Michael Faraday had demonstrated gutta-percha's insulating properties in 1843. By 1850, the Gutta Percha Company in London was producing insulated wire for submarine applications. Without this specific material, available from the recently colonized Malayan peninsula, submarine telegraphy would have been impossible.

The first successful permanent cable connected England and France in 1851—protected this time by iron wire armoring. Over the next decade, cables linked Britain to Ireland, crossed the Mediterranean, and crept around the coastlines of continents. But the ultimate prize was the Atlantic. A cable connecting London to New York would cut communication time from two weeks (by the fastest steamship) to minutes.

Cyrus Field, an American paper merchant with no technical background, devoted himself to this goal with manic persistence. He crossed the Atlantic 56 times in the course of the project, raising capital in both countries and navigating political obstacles. The Atlantic Telegraph Company he formed represented an unprecedented investment: the cable itself cost over £500,000, and the expedition required naval vessels from both the United States and Britain.

The first Atlantic cable, laid in 1858, worked for three weeks before failing—probably destroyed by the excessive voltage Wildman Whitehouse, the chief electrician, used to force signals through. The American Civil War delayed further attempts. But in 1866, after one more failed attempt, the Great Eastern—then the largest ship ever built—successfully laid a working cable from Ireland to Newfoundland. A message that had taken two weeks could now cross in minutes.

The scientific advances demanded by the project transformed electrical engineering. William Thomson (later Lord Kelvin) developed the mirror galvanometer and siphon recorder to detect the minute currents arriving after 2,000 miles of transmission. His work on signal propagation in long cables established principles that would later govern telephone and data transmission. The cable companies became testing grounds for precision instrumentation and electrical theory.

By 1900, a web of submarine cables connected every continent. The British Empire's strategic position became partly a function of cable control—nearly all international telegraph traffic passed through British stations. The global communications network that would eventually include telephone, radio, and internet fiber optics began with copper wires wrapped in tree sap and laid on the ocean floor by Victorian engineers who barely understood the physics of what they were doing.

The submarine cable demonstrates how enabling materials constrain invention. Without gutta-percha from Southeast Asian forests, the technology was impossible. The adjacent possible opened when colonial expansion made this specific material available in industrial quantities. Geography and botany determined the timing of global telecommunications as surely as any engineering insight.