Charles Benedict Calvert telegraph, Samuel Morse and Alfred Vail. On April 9, 1844, Morse and Vail successfully tested their device by transmitting a message from the nation's capital to the Calvert home, Riversdale. This test came 45 days before the more celebrated event when Morse sent the message "What hath God wrought?" from Washington to Baltimore, along telegraph lines that ran above the Baltimore and Ohio Railroad line near Riversdale. Calvert became president of the Prince George's County, Maryland Agricultural Society and the Maryland State Agricultural Society, and served as vice president of the United States Pomological Society. He founded the first agricultural
Morse code and most versatile methods of telecommunication. The most common distress signal is SOS – three dots, three dashes, and three dots – internationally recognized by treaty. Beginning in 1836, the American artist Samuel F. B. Morse, the American physicist Joseph Henry, and Alfred Vail developed an electrical telegraph system. This system sent pulses of electric current along wires which controlled an electromagnet that was located at the receiving end of the telegraph system. A code was needed to transmit natural language using only these pulses, and the silence between them. Around 1837, Morse, therefore, developed an early forerunner to the