In the early forties of the 20th century, Western Union has used the first time a commercial intercity microwave transmission system. In 1877, starting from September, New York City residents began to have the opportunity to check the time on clock with the "time ball", located on the roof of constructed in the same year a new corporate headquarters - Western Union Building. In 1849, Selden and Sibley, the founders of the future Western Union, created the New York State Printing Telegraph Company. Western Union made so that the time in all of American civil services was the same. In 1884 Western Union has become a joint-stock company and was brought to the stock exchange. The company has entered in the first American stock index Dow Jones.