Found in:ExploratoriumTen Cool Sites: October/November 2005http://www.exploratorium.edu/learning_studio/sciencesites.htmlDeafness in Disguise: Concealed Hearing Devices of the 19th and 20th Centuries - Deafness in Disguise presents images, illustrations, advertising pamphlets, trade catalogs, patents, rare books and other material pertaining to mechanical and electrical hearing devices from the 19