Telegraph Register
From the collection of National Museum of American History. Free to download, adapt and use — no permission needed.
In 1849 Samuel F. B. Morse received U.S. patent #6,420 for an “improvement in electric telegraphs.” This patent model demonstrated a refinement Morse made to his original telegraph register. Rather than using electromagnets and a lever arm to emboss or ink the dots and dashes on the paper tape, this unit took advantage of the ability of some salts to make colored marks on paper in response to an electric current. Morse described several methods in his patent using different types of salts. Never widely adopted, Morse’s refinement was mostly intended as a response to rival Alexander Bain’s chemical telegraph invention three years earlier.
National Museum of American History’s own description
