Graphoscope Negretti & Zambra Great Exhibition of 1851 Hanau, Eugène Hand-held stereoscope Hautecoeur Hermagis Hodent, Louis Joseph Holmes-Bates stereoscope Holmes, Oliver Wendell Sr. Hyalotype Johns patent Kilburn viewing case Kilburn, William Edward Knight, George & Sons Langenheim brothers Latimer Clark system Le Conte Stevens patent Lee, James Lévy patent Lewis family Lewis, Henry J. patent Lewis, William H. combined stereoscope Lewis, William H. patent graphoscope London Stereoscopic Company Lorgnette Lowden, George Loyd patent Loyd’s American Stereoscope Lyons patent Marinier, Jules