Unpublished letter, regarding a system of communicating signals from J Henry Doyle to the President of the Royal Society of Arts Doyle introduces his system of communicating signals using flags corresponding to numbers for confidential communication. He also developed a system using laterns for signalling at night. Doyle envisions possible use of the signalling system in the Navy. Includes four sets of illustrations in the text. Subject: Communication Written by Doyle in Wexford, Ireland and erroneously addressed to the President of the Royal Society of Arts. 8 May 1828