from from www.ghost-sighting.co.uk/
Dowsing Rods
Traditionally, a forked branch or stick that is believed to indicate subterranean water or minerals by bending downward when held over a source. Divining rod, a rod, commonly of witch hazel, with forked branches, used by those who discover water or metals under ground.
Dowsing or divining rods can also be made of metal, and bent in an “L” shape – one for each hand. In ghost hunting, when the rods cross while being held out in front of the “dowser” they indicate spirit presence at the spot the dowser is at.