[Health]. North, Alfred Augustus and Justus Abner. Voxometric Revelation The Problem Surrounding the Human Voice Finally Discovered The Source and Origin of the Voice of Mankind Revealed for the First Time Also a True and Complete Theory for the Production and Training of every character of Voice, both in Song and Speech, to the highest development of the Individual, upon One Grand Basis. London: Authors' & Printers' Joint Interest Publishing Co., 1896. 215mm x 145mm 208 pp. Original blue cloth covered boards. Black and white illustrations. Front hinge tender, very good.