HALL, Edward. The Rediscovery of Truth by the Solar and Other Spectra. London: George Routledge & Sons, 1923. 8vo. Frontispiece illustrated in gold, blue and red, with 34 other plates, some as illustrations within the text and some as full colour plates (some mild occasional spotting, endpapers browned ). Contemporary blue cloth, spine titled in gilt, titles to upper board in blind (boards a little faded). SIGNED by Edward Hall in black ink to the front endpaper. With 3 other works: Renee Haynes' The Hidden Springs, An Enquiry into Extra-Sensory Perception. London: Hollis & Carter, 1961. 8vo. Contemporary pin cloth with grey and white illustrated dust jacket (some chipping with loss to spine head). SIGNED by Haynes on the front endpaper in blue ink. Provenance: Ink stamp of The Centre for Spiritual and Religious Studies. Eric F. W. Powell's Balance Physical Spiritual Intellectual. London: The C. W. Daniel Company, 1934. 8vo. (Offsetting from dustjacket to endpapers). Original blue cloth, with yellow/brown illustrated dustjacket. SIGNED by Powell in blue ink to the front endpaper: "To Gloria, the lady of the dedication with every good thought". Beatrice Irwin's The Gates of Light A Record of Progress in the Engineering of Colour and Light. London: Rider & Co., [n.d]. 8vo., colour frontispiece, 9 plates. Contemporary purple cloth (faded). SIGNED on the front endpaper by Irwin in purple ink: " To 'Colmia' joyous in good works with love from Beatrice I. The flight of friendship is akin to the stars Nov: 14- 1930". (4)