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
Telegraph sounder 1850s to the 1920s to transmit text messages long distances, transmitted information by pulses of current of two different lengths, called "dots" and "dashes" which spelled out text messages in Morse code. A telegraph operator at the sending end of the line would create the message by tapping on a switch called a telegraph key, which rapidly connects and breaks the circuit to a battery, sending pulses of current down the line. The telegraph sounder was used at the receiving end of the line to make the Morse code message audible. Its simple mechanism was similar to a relay. It