Dowsing, or Radiesthesia as it is know by its scientific term, is energy detection. Dowsing has been used by man for thousands of years. Many different items have been used in dowsing, items such as forked branches, pendulums, rods, and even jewelry.

Dowsing has been employed for many things. Dowsing has been used to determine the  location of water supplies, the sex of  babies while still in the womb, lost items, and, oil/mineral deposits just to name a few.

In 1913 Dr. Richet, a Nobel prize winner, published a book entitled  Traite de Metapsychique. He established dowsing as a fact.

In 1934 the Pope relied on the abilities of a dowser to locate the position of  explorers that were stranded near the north pole. Abbe Mermet was able to dowse the exact location of the stranded people, using a map and a pendulum.

PROS staff have experimented with dowsing, our results were beyond chance. There are a lot of references written on the subject of dowsing. The most common belief is that the dowser is able to sense the energy fields which seem to radiate from anything and everything.

It should be noted doubt seems to play a large part when dowsing. Much like other psychic gifts, dowsing works best with an open mind.

Note : I met Harold McCoy a dowser he helped with the return of the harp by way of dowsing! -

http://whitecrowbooks.com/michaelcocks/entry/stolen_harp_recovered_using_dowsing