Sensible post Sweep I only slightly disagree on one point /suggestion .
"Nor is there any doubt that people can trace things they don't know are there by other means. " .
Water is one thing but previously unrecorded and unsuspected archaeology is a bit different ,any examples ?
I wasn't entirely clear there. My apologies. I was thinking of cases like the dowser who traced the water main in my earlier example, plus cases such as the one I obvserved in the grounds of Glastonbury Abbey, where someone who'd never dowsed before found and followed a line of earth energy (whatever that is. I've traced it many times but we just have a name for it, not an explanation) which took a meandering course and then entered part of the buildings through a wall near a doorway at an odd angle. I kept well back so as not to influence the young lady who did this.
I've never dowsed archeological remains, which would be very interesting, especially in the case of unknown remains that were subsequently detected. The story in the next person's post to th one quoted is interesting, in which traces were found by dowsing than nothing was there. Such awkward failures need thorough investigation as well as the successes, I think, first to rule out sheer chance with the successes, and second to investigate whether something else was being detected and the fault was with the interpretations of the dowsers and not with the dowsing itself. We're really at a very basic level with investigating this stuff.