cockney steve wrote:
Thanks for your explanation , which, whilst being totally credible, does not explain the old country -craft of using a forked Hazel twig as the "divining-rod"
Well I've generally found dried out Bic biros and scrap lengths of TC&E more readily available than hazel twigs, forked or otherwise !
I suspect that the twin "forked" legs of the hazel twig, with mineral loaded sap, act as conductors in much the same way as 2 copper wires.
Try out the method I suggested (not my invention, I can't claim credit). Hold the plastic biro barrels tilted slightly forward, so that the copper wires are pointing ahead, and slightly downwards (to prevent them from swinging all over the place), and walk steadily.
Bill H