ScientificAmerican1902-02-15.jpg Scientific American 1892-05-28ThumbnailsScientific American 1902-03-15Scientific American 1892-05-28ThumbnailsScientific American 1902-03-15Scientific American 1892-05-28ThumbnailsScientific American 1902-03-15Scientific American 1892-05-28ThumbnailsScientific American 1902-03-15Scientific American 1892-05-28ThumbnailsScientific American 1902-03-15
Assaying gold and silver bullion at the new york Assay Office. Weighing Room. Melting. Pressing the assay sample. Muffle furnaces for fire assay. Humid assay for silver. Extracting the silver with boiling acid.



Source: Steve Kirch, collector, and creator of a great website about SCIENTIFIC AMERICAN in the past

Restoration by: magscanner