Part of the Smithsonian collection…
The telegraph key Samuel Morse used on his first line in 1844 was very simple–a strip of spring steel that could be pressed against a metal contact. Alfred Vail, Morse’s partner, designed this key, in which the gap was more easily adjustable because of changes in its spring tension. It was used on the expanding telegraph system, perhaps as early as the fall of 1844 and certainly by 1845.