The Smithsonian Institution, founded this month in 1846, is the world’s largest museum and research complex, with 138 million artifacts in its collection. One was donated to the museum in August 1985 to mark the 25th anniversary of its commercial debut — the original Xerox 914 copying machine. The principle of xerography — producing images on paper using electricity — was developed in 1938 by lawyer-scientist Chester Carlson, who saved future generations from having to deal with carbon paper and mimeograph stencils. Some 216 U.S. companies make photocopiers and other photographic equipment. The value of their shipments is over $1.7 billion a year. You can find more facts about America from the U.S. Census Bureau online at <www.census.gov>.