Gallery of great ideas: The telegraph

Dits to bits

Humans learned to communicate before we were humans. Animals of all kinds communicate. But when we learned to talk, our social capacity increased many-fold, allowing us to exploit new niches and eventually become the dominant vertebrate species on earth.

Writing expanded our social capacity further, by enabling communication across time. What I write today, you can read tomorrow or next year and your grandchildren can read next century. Writing facilitated the permanence of cultures. Jewish culture has survived for three thousand years, Christian culture for two thousand, and Muslim for fifteen hundred, each based on written scriptures. Other religions and traditions have comparable sorts of literary cement.

Yet until the nineteenth century, communication across space was limited by how fast a human carrying the message could travel. Exceptions to this rule—drums, smoke signals, carrier pigeons—were few and collectively inconsequential. The human courier might transmit the message orally, telling it to the recipient, or by delivering a letter. The courier might travel afoot or on horse. But physiology put a low upper bound on the speed of communication.

Then, in the 1830s, Samuel Morse and others, building on a century of work in electricity, conceived a scheme for sending information down a wire. For the first time, communication was liberated from transportation. The physics of electrons, rather than the physiology of flesh and blood, set the speed at which humans could communicate.

The new technology was called telegraphy, from the Greek for “distant writing.” It revolutionized communication, especially in countries like the United States with large territory. When gold was discovered in California in January 1848, the news took months to reach Washington and New York. After telegraph wires were strung to California, similar news required mere seconds or minutes (allowing for relays to boost the signal).

Indeed, had the telegraph been in existence at the time of the gold discovery, the history of California might have proceeded differently. The negotiations to finalize the transfer of California from Mexico to the United States at the end of the war between those countries were still under way when James Marshall stumbled on gold on the American River. Had his discovery, and hence the presumptive value of California, become known to the diplomats, the negotiations might have taken a different turn. At the least, Mexico would have demanded a higher price for ceding that part of its patrimony. But the Treaty of Guadalupe Hidalgo was consummated in ignorance of Marshall’s find.

The telegraph tied the American economy together, providing price and other information to producers and consumers hundreds or thousands of miles apart. After telegraph cables were laid across the Atlantic in the 1850s and 1860s, American producers could know immediately of changes in the European price and demand for wheat and other commodities, and modify their behavior accordingly.

The telegraph helped hold the American Union together. During the Civil War, Abraham Lincoln kept a chair at the telegraph office of the War Department. He monitored the performance of his generals, finally settling on Ulysses Grant, the Union hero of the West, who led the Union armies to victory over the Confederacy. (It was in the telegraph office, as well, that Lincoln drafted the preliminary Emancipation Proclamation.)

Swifter communication wasn’t an unmixed blessing. The telegraph wires flashed alarm across the country during financial crises. Before the telegraph, a bank failure in one city rarely had ramifications far away. But the telegraph made bank panics in 1857 and 1873 nationwide events, and a panic in 1893 a trans-Atlantic phenomenon. 

The telegraph gave rise to the telephone, when Alexander Bell figured out how to push voice signals down wires, and radio, when Guglielmo Marconi and others realized that electromagnetic waves could carry signals through the atmosphere. These successor technologies, and technologies they in turn spun off, largely supplanted the telegraph; most people in the twenty-first century have never sent or read a telegram.

Yet a continuing aspect of telegraphy is ubiquitous. No less important than his work with electrical signals was Samuel Morse’s insight that information could be coded in binary form—the dots and dashes, or dits and dahs, of Morse code. Nearly two centuries later, that’s how the world still codes information.

-.. ..- …. , he might have said.