until after 12 years’ service for others which differ only from conviction based on ample documentary material. J. T. Sutcliffe, The Iistory of Engraving and Etching, 3rd ed. (1912); Franz Prasil, Technische Hydrodynamik (1913); T. W. Arnold, The Preaching of Islam (1913); “Muhammedanism,” Encyclopaedia of Religion