This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Ptska. Chem Laboratorium Karlsruhe scan before author PDold original upload log de Leyo CommonsHelper page de Ptska Muellerb bytes no Andere Versionen Karlsruhe Institute of Technology History of Karlsruhe
Page 2023 Free-images.com. All images are Public Domain