John Armstrong was an American civil engineer and soldier who served as a major general in the Revolutionary War. He was a delegate to the Continental Congress for Pennsylvania.

A portrait of Robert Fulton from the Dibner Library of the History of Science and Technology, made available through the Smithsonian Institution's Scientific Identity Collection.

A portrait of Guglielmo Marconi from the Dibner Library of the History of Science and Technology, made available through the Smithsonian Institution's Scientific Identity Collection.

A portrait of Samuel Finley Breese Morse from the Dibner Library of the History of Science and Technology, made available through the Smithsonian Institution's Scientific Identity Collection.

Portrait of Tyndall.

A planchette.