Read this: In 1875, Bell developed an acoustic telegraph and drew up a patent application for it. Since he had agreed to share U.S. profits with his investors Gardiner Hubbard and Thomas Sanders, Bell requested that an associate in Ontario, George Brown, attempt to patent it in Britain, instructing his lawyers to apply for a patent in the U.S. only after they received word from Britain (Britain would issue patents only for discoveries not previously patented elsewhere).
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What kind of telegraph did Bell create?
acoustic