Very interesting stories, guys.
A couple of years ago, when I was still planning the pond project, I got ahold of the original owner of not only my property, but also owned the surrounding farm property. He moved there as a boy in 1935.
During our enlightening conversation, I quizzed him on the location of any drainage tiles. He gave me verbal, generic locations...then told me to witch 'em. He described the same pc of copper wire. So I made a set and went out and tried it. I was disappointed with the lack of any results. I tried to balance the rods so they would not move, like my fingers were knife edges on a triple beam scale. I couldn't get the wires to stay straight and still as I moved. I didn't want to hold them any tighter, figuring that this unknown force that would draw them together would be too weak to rotate the vertical wire portion in my hands. Anyway, they kept moving left and right, mostly based on the way I cocked my wrists. I gave up after about 20 minutes. Besides, I was witching for a drain tile that, at that particular time, would not have had water in it. Based on what Dave noted, maybe I would not have found it anyway...?
So, PB witchers...tell me. Can you grip the wires snugly enough to stabilize them from rolling left and right (basically pointed straight away), and still expect the force from below to move them together?