Book Harmonium 19th century French or German A book organ (or bible regal) was a popular type of small pipe organ that when folded up took the shape of a large book. This instrument takes that much older idea and updates it with a free reed harmonium in the 19th century. Technical description: Softwood case in form of four leather-bound folio size books, the cover and spines stamped with gold floral designs, and labeled on the spines: Traite des Pais Bas Tom I (II, III, IV); volume one hinges upward, revealing an engraving of the Supper at Emmaus glued beneath the lid; inside, a keyboard (oak levers, ebony naturals, ivory accidentals; compass F-c2) is at the front of the compartment, separated by a partition from a leather-covered (painted pink) reservoir behind, the reservoir (compressed by two springs and bearing a safety valve on top) mounted above a single fold feeder operated by a handle extending through the lower left rear side of the case; the boxwood handle terminates in the f