Divination

Epreuve par la baguette = directly translated means Evidence By the Wand

wiki

Dowsing is a type of divination employed in attempts to locate ground water, buried metals or ores, gemstones, oil, gravesites,[1] and many other objects and materials, as well as so-called currents of earth radiation (Ley lines), without the use of scientific apparatus. Dowsing is also known as divining (especially in reference to interpretation of results),[2] doodlebugging (in the US)[citation needed], or (when searching specifically for water) water finding, water witching or water dowsing.[3]

this completely baffles me, and apparently it works.