The Atlantic Cable
Before the trans-Atlantic telegraph cable was completed, the only way to get messages to and from Europe and the New World was by a two-week trip on a ship. The cable, laid in 1858, was twenty-five hundred miles long and the first of its kind. Submarine cabling wasn’t even possible until the discovery of the material gutta-percha ten years earlier. This cable became the world’s first million-dollar business venture, with the bulk of the funding coming from an American businessman named Cyrus West Field. A working trans-Atlantic cable to communicate across the Atlantic Ocean in 1858 was the most significant technological achievement at the time, on the same scale as man landing on the moon one hundred years later. The issue with submarine cables The first commercial Telegraph line ran from Washington, D.C., to Baltimore, Md., in 1844. Telegraph lines were run overhead, and thousands of miles of cable were run each week worldwide.
Figure 3. The Main Cable
Telegraph engineers had trouble running cable underground or underwater because the dielectric insulation was never good enough. The British discovered a type of natural plastic called gutta-percha in India, which acted as a perfect insulator for undersea cables. The discovery and effects of gutta- percha on civilization cannot be overstated. It is on the scale of discovering fire or inventing the wheel. Someday, it would make a good Retro Electro article. The first successful submarine telegraph cable was laid in 1850, and soon after, telegraph cables were first being run underground and underwater, and a new phenomenon that seemed only to affect submarine and buried cables, called retardation (signal
propagation delay), was uncovered. Over a long distance, the submarine cables would have a delay in their signals. Something that would take seconds to transmit using above- ground cabling would take minutes over the same length of underwater cabling. Dots and dashes would be stretched out and blurred together, and if the operator transmitted too fast, the receiving operator wouldn’t be able to decipher it. Telegraphs essentially work by passing a current through a wire to cause an effect at the other end. Today, we think of telegraphs as a bunch of beeps and boops, but do you think they had speakers in the 1850s? Telegraph receivers of this time used visual mechanisms to read messages. Common methods included needle instruments, where the needle would move in response to electrical signals, or recording devices that printed symbols on paper. Whitehouse used a form of electrochemical recording that marked electrically sensitive paper. At the same time, William Thomson
Fun fact: Morse sent the world’s first commercial telegraph from Washington DC to Baltimore, Maryland, in 1844, asking, “What hath God wrought?”
we get technical
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