
Prototype 'duette' system concertina. No serial number. Faint oval stamp in rosewood of right-hand end: 'By Her Majesty's Letter Patent, Wheatstone & Co, Inventors, 20 Conduit St, London.' 6" x 4.63" rectangular rosewood ends, simple frets, leather backing, four wood screws. 24 keys: 12 each side. Note names embossed on brass buttons on levers (1 right-hand missing), simple fretting. Both straps absent, with only right-hand hand bar present. Large brass screws. Four-fold green bellows with white/gold star papers. The duet system was patented by Wheatstone in 1844, but not fully developed until MacCann's patent in the 1880s.