321. The Electric Telegraph
Benjamin Franklin and Joseph Henry made great discoV - eries in electricity . But Samuel F . B . Morse was the first to use electricity in a practical way . Morse found out that if a man at one end of a line of wire pressed down a key , electricity could be made at the same moment to presS down another key at the other end of the line of wire . Moreover , the key at the farther end of the line could be so arranged as to make an impression on a piece of paper that was slowly drawn under it by clockwork . Now if the man at one end of the line held his key down for only an instant , this impression would look like a dot . If he held it down longer , it would look like a short dash . Morse combined these dots and dashes into an alphabet . For instance , one dash meant the letter ＂ t ,＂ and so on . For a time peo - ple only laughed at Morse . But at length Con - gress gave him enough money to build a line from Baltimore to Washington . It was opened in 1844, and proved to be a success from the beginning . Other lines were soon built , and the Morse system , greatly improved , is still in use . The telegraph made it possible to operate long lines of railroad , as al the trains could be man - aged from one office so that they would not run into one another . It also made it possible to communicate with people afar off and get an answer in an hour or so . For both these reasons the telegraph was very important and with the railroads did much to unite the people of the different portions of the country .
用户评论