{"collection":"aor","html_url":"https://unchartedknowledge.5gfusion.net/browse/aor/dv/0647.htm","path":"aor/dv/0647.htm","source_url":"https://sacred-texts.com/aor/dv/0647.htm","text":"The Da Vinci Notebooks\nPut marcasite into aqua fortis and if it turns green, know that it has copper in it. Take it out with saltpetre and soft soap.","title":"Vol. I: IX. The Practice of Painting: 647.","type":"page"}