Correspondence with the South Eastern Railway and the Electric Telegraph Company and related papers concerning galvanic signals. The papers cover the trials of the Greenwich Mean Time signal between Greenwich and London and Greenwich and Dover, and proposals for and implementation of an extension to the central Telegraph Office, Lothbury, London. There is also correspondence with the Electric Telegraph Company on the time ball service in the Strand, activated from Greenwich by telegraph, and on the use of a systemised time service. The correspondents include C.V. Walker and J.C. Clark.