Samuelson, Arnold: Flight Velocity, published 1906, with author's theories for a 'Rowing Flyer', fold-out diagrams and some slightly disparaging views of the Wright brothers (rebound with numerous blank pages); Gormon, O: Problems Relating to Aircraft, 1911 and McCallum, A: The Navigation of the Air, published by the aeronautical Society 1897 (all three volumes handsomely rebound with green cloth boards, dark green spines and leather corner pieces) and Robertson, F.A.V: Aircraft of the World, 1924 (some old damage to the decorated front cover) (4)