Rare circa 1860s Caton lineman's pocket telegraph set, as used by spies during the Civil War. Measuring just 5″ x 2.25″ x 1.25″ in its hard rubber case (engraved "P. H. Lovell" on the lid), this is a complete ultra-portable telegraph sending and receiving system. During the Civil War, telegraph operator spies used these to tap into the enemy's communications systems: a bare wire tossed over uninsulated telegraph lines—and grounded with a bayonet—allowed them to intercept messages or send along false intelligence. This diminutive unit features horizontally mounted sounder coils, a 1.5″ strap telegraph key, and a tiny shorting switch. The center piece is engraved with the maker's name, "Caton, Ottawa, Ill." In fine condition. These were also known as a pocket telegraph machine, cavalryman's portable telegraph key, or Caton Pocket Relay. At the time of their use, the Caton was the highest quality machine on the market.