At that time, he was assisting Samuel Morse in inventing Morse telegraph (1835).
Although Morse invented the telegraph, he lacked relevant professional knowledge. He signed an agreement with Alfred Weil to help him make more practical equipment. Alfred Weil conceived a scheme in which each character and punctuation can be sent independently of each other through dots, strokes and pauses in the middle. They agreed to include this scheme of marking different symbols in Morse's patent. This is now known as American Morse code, which was used to transmit the world's first telegram.