United States. Patent and Trademark Office. “Patent for Defluorinating Rock Phosphate by Kelly L. Elmore,” February 6, 1945. Papers of Georg and Max Bredig, Box 10, Folder 34. Science History Institute. Philadelphia. https://digital.sciencehistory.org/works/i3e8xuq.
Also
Mouse click to zoom in; shift-click to zoom out. Drag to pan. Pinch to zoom on touch.
The Science History Institute recognizes there are materials in our collections that may be offensive or harmful, containing racist, sexist, Eurocentric, ableist, or homophobic language or depictions. The history of science is not exempt from beliefs or practices harmful to traditionally marginalized groups. The Institute is engaged in ongoing efforts to responsibly present and address the evidence of oppression and injustice inextricable from the history of science. If you would like to learn more about our ongoing efforts or if you encounter harmful, inaccurate, or insufficient descriptions, please contact us at digital@sciencehistory.org.
Public Domain
