From Eric Sloane’s Weather Almanac:

A few of the old-timers still use divining rods to "witch" water or locate springs underground. When they hold a forked willow stick with both hands and walk slowly around a well site, a mysterious pull is supposed to exert itself and pull the point of the V toward the nearest water. The divining rod is also used to locate underground tiles, hidden pipes, hidden treasure or whatever the witcher has faith in it to do.

One of the local well diggers has devised a chromium divining rod. It is made from two welding rods, three-sixteenths of an inch thick and three feet long. After six-inch handles are bent in the rods, and when they are held broomfashion with the long parts horizontal to the ground and a few inches apart, the rods are supposed to come together when you are above a "find." He says he uses it as a gag, but still it is part of his equipment and I wonder how much of a gag it really is. He copied the plans, incidentally, from a 1954 almanac which gives complete specifications for making and using it.