Keyboard diagrams for the most important concertina
fingering systems: English, Anglo, and Maccann Duet, plus Early Wheatstone Double Duet,
Early Wheatstone "Duett" Duet, Crane (or Triumph) Duet, Jeffries System Duet,
Late Wheatstone Chidley Duet, and Hayden (or Wicki) Duet.
A unique collection of nearly 40 pricelists for vintage concertinas,
mostly found in old concertina cases. From internal evidence it is
possible to date the Wheatstone pricelists with more or less accuracy, but the Lachenal pricelists
and others from dealers still have some uncertainty in dates.