Lifelike Baseball Scoreboard

Washington, D.C., inventor George Coleman's "Lifelike Baseball Scoreboard" was set up in movie theaters to "broadcast" the home team's away games. "It contains 19,000 feet of wire and has 400 stereopticon slides with an electric light bulb for each slide. Five men are required to operate the great board, including the telegraph operator who receives play-by-play from the field."

Via Shorpy Historic Picture Archive

Thanks Bruce!