Chemistry: various crystalline salts. Engraving by Prevost after L.J. Goussier. https://www.rawpixel.com/image/14015149/chemistry-various-crystalline-salts-engraving-prevost-after-lj-goussierFree Image from public domain licenseChemistry: various crystalline substances. Coloured engraving. https://www.rawpixel.com/image/14021817/chemistry-various-crystalline-substances-coloured-engravingFree Image from public domain license