SCIENCE PHOTO LIBRARY SCIENCE PHOTO LIBRARY
Ducretet apparatus. This device was invented by the French instrument maker Eugene Ducretet (1844-1915). The design includes Ruhmkorff coils (solenoids), with part of the apparatus immersed in oil (right). Similar designs were used for Ducretet's oil break spark key (used in telegraphy) that prevented sparks that could ignite flammable gases. Artwork from the ninth volume (first period of 1892) of the French popular science weekly 'La Science Illustree'.
Model release not required. Property release not required.