Dowsing is commonly used to find water or other substances hidden underground. Hiring a professional Dowser to map property before digging a new well was a fairly common practice in the US as well as in Europe until fairly recently, and there are those who still engage in that profession today. This technique of detecting energy is ancient, and practiced widely around the world, even by those who don’t consider themselves “Pagan”.
Dowsers usually use a "Divining Stick" or Dowsing Rod to detect the flow of hidden energy. The dowsing rod is held lightly in both hands as the dowser walks slowly over the piece of land to be mapped. The rod generally pulls strongly downward toward the earth in response to the presence of whatever is being sought.
In a Pagan context, people often use dowsing rods to map out natural energy flows within the planet, called "ley lines". These are basically energy currents that flow through points of the earth. It is believed that monuments such as Stonehenge and the pyramids are built along "ley lines". Mapping local ley lines helps a Witch attune the energy of where they live.
~Flame RavenHawk