9.4.3. Water witching, the practice of using the move- ments of a forked twig to locate underground water (or minerals), dates back over 400 years. Its first detailed description appears in Agricola's De re Metallica, pub- lished in 1556. That water witching works remains a belief widely held among rural people in Europe and through- out the Americas. [In 1960 the number of "active" water witches in the United States was estimated to be more than 20,000 (193).] Reliable evidence supporting or refut- ing water witching is hard to find. Personal accounts of isolated successes or failures tend to be strongly biased by the attitude of the observer. Of all the wells dug in Fence Lake, New Mexico, 29 "witched" wells and 32 "non- witched" wells were sunk. Of the "witched" wells, 24 were successful. For the "nonwitched" wells, there were 27 successes. What would you conclude