ScientificAmerican1921-04-02.jpg Scientific American 1921-03-26ThumbnailsScientific American 1921-04-09Scientific American 1921-03-26ThumbnailsScientific American 1921-04-09Scientific American 1921-03-26ThumbnailsScientific American 1921-04-09Scientific American 1921-03-26ThumbnailsScientific American 1921-04-09

"Taking the dents out of damaged brass instruments" in a musical instruments repair shop.