ScientificAmerican1920-10-23.jpg Scientific American 1920-10-09ThumbnailsScientific American 1920-10-30Scientific American 1920-10-09ThumbnailsScientific American 1920-10-30Scientific American 1920-10-09ThumbnailsScientific American 1920-10-30Scientific American 1920-10-09ThumbnailsScientific American 1920-10-30
Melting gold coins in the United States Assay Office.