VOLKERT Ingenieur Chr. Modell einer liegenden Dampfmaschine mit Meyer'sher Expansions - Schieber - Steuerung (c.1897) German text, coloured drawings, valve timing etc, boards, (loose pages); GEORG R. Der Maschinenbau exploded coloured drawings of various steam engines e.t.c. paper (torn) ALBRECHT K. Zerlelegbares Modell der Westinghouse-Schnellbreuze German text, drawings and exploded coloured drawing, original board (worn) (3)