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.
Flasza.Woulfa. Woulfe bottle bubble bottle marked as used in hydrogen generator Orgelbrand Encyclopedia Vol XV page Warsaw by author PDOrgelbrand Hydrogen technologies Woulfe's bottles
Page 2023 Free-images.com. All images are Public Domain