Friedrich Heinrich Alexander von Humboldt. Line engraving by A. Krausse, 1814. https://www.rawpixel.com/image/13991838/friedrich-heinrich-alexander-von-humboldt-line-engraving-krausse-1814Free Image from public domain license
Civil engineering: various bridges, ancient and modern, around Europe, the Ponte Vecchio, Venice, in the centre. Engraving… https://www.rawpixel.com/image/13991568/image-cartoon-pattern-skyFree Image from public domain license
Friedrich Heinrich Alexander von Humboldt. Line engraving by A. Krausse. https://www.rawpixel.com/image/14018124/friedrich-heinrich-alexander-von-humboldt-line-engraving-krausseFree Image from public domain license
Friedrich Heinrich Alexander von Humboldt. Line engraving by A. Krausse, 1850. https://www.rawpixel.com/image/14000289/friedrich-heinrich-alexander-von-humboldt-line-engraving-krausse-1850Free Image from public domain license
Apparatus for coal mining and two illustrations of coalmines. Engraving by A. Krausse for G. Heck. https://www.rawpixel.com/image/13985995/image-cartoon-person-artFree Image from public domain license