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Originally published in the Journal of  the Society for Psychical Research Vol. 51, No. 792, October 1982, pp. 343-367. DOWSING: A REVIEW OF EXPERIMENTAL RESEARCH  by GEORGE P. HANSEN* 

BIOPHYSICAL INVESTIGATIONS 

   To the orthodox scientific community, probably the most acceptable method of studying dowsing is through biophysics. This approach assumes that some humans may be able to detect low levels of known types of radiation in a little understood manner. The most widely cited investigators using this approach who have published in English include Maby and Franklin, Tromp, Rocard, Harvalik, and Chadwick and Jensen. 

   A book published in 1939, The Physics of the Divining Rod (currently available from University Microfilms), described the experimental investigations of J. C. Maby and T. B. Franklin, who concluded that ordinary dowsing sprang from a special physiological faculty which could be explained along classical scientific lines (Maby, 1941). Although this work is often cited, the published reviews have frequently been unfavourable. The reviewers for the Society’s Journal and for Nature assert that the experiments are not well enough described to evaluate (C. C. L. Gregory, 1940, 1941; Ellison, 1969; and The Physics of the Divining Rod, 1940). 

   One of the most extensive works describing experimental research on dowsing from a biophysical viewpoint was written by Dr. Solco W. Tromp. Tromp, a Dutch professor of geology, has produced numerous articles on geology and two books on medical subjects and served as the director of the Bioclimatological Centre in Leiden. His most widely cited book in psychical research is probably Psychical Physics (reviewed by Robertson, 1950; R. Wilson, 1951). Much of this reviews literature concerning the effects of electric, magnetic, and electromagnetic radiation on biological organisms. It also surveys the literature on geophysical fields and meteorological fields such as radioactivity and air ions, and—more briefly—some tests conducted in both laboratory and field conditions to determine levels of sensitivity in dowsers, and the physiological changes they experienced during dowsing. The volume covers many areas; the bibliography cites 1496 items the majority not in English. Tromp (1955, 1968, 1972) has also published brief articles dealing with additional research findings and summarizing some of the material in his book. 

   Tromp conducted tests to determine dowsers’ sensitivity to magnetic fields in the laboratory. A tangent galvanometer with a wooden ring of 1.0 meter diameter and one coil of wire was used to create a magnetic field. The galvanometer was equipped with a reportedly noiseless switch and noiseless  swivel. For many of the tests, dowsers used a U-shaped rod. Tromp found that dowsers could detect changes in the strength of an electromagnetic field (for instance, by walking through an area with a varying field strength, by switching current on or off, or by changing the direction of the field) but could not detect the field strength itself. His experiments showed that sensitive dowsers could detect gradients of less than 0.1 gauss per meter (the strength of the earth’s field is roughly 0.5 gauss, a child’s magnet is of the order of 1,000 gauss).

After 20 trials the dowsers became fatigued and could not respond accurately, but for the first twenty trials, those he found sensitive responded correctly 80 per cent of the time. The tests with the tangent galvanometer were conducted with the dowsers blindfolded and with cotton-wool placed in their ears. The person recording the responses was not aware the current was on or off; however, the experimenter controlling the switch was in the same room as the dowser. Tromp noted that some dowsers took up to eleven seconds to respond to the change in the electromagnetic field; but did not mention how the length of each trials was established or the actual number of subjects, trials, or successes. 

   In other tests conducted with the artificial magnetic fields, dowsers used pendulums. Tromp found that persons not sensitive to the artificial fields when using the loop shaped rod, were sensitive when using the pendulum; and also that, in contrast to findings with the rod, persons using a pendulum could detect differences in field strength. The numbers of subjects, trials, and successes were again omitted. 

   Tromp reported moreover that dowsers could detect electrostatic fields. The experiments are described briefly and the level of experimental control undertaken is not clear. 

   Tromp also tested dowsers under field conditions. Dowsers were led along a path in a house, and locations where dowsing reactions occurred were noted. For most of the experiments, dowsers used pendulums as dowsing instruments because Tromp found that they produced the quickest reactions. A magnetic survey was made afterward along the same path. Definite correlations were found between the ‘dowsing zones’ and the magnetic disturbances. Dowsers were also tested out of doors to determine if they could locate subsurface discontinuities which could not be predicted by even very experienced geologists or botanists. They traversed a pre-assigned path and their reactions were recorded. A soil resistivity survey was made after the dowsing tests (resistivity surveys indicate underground discontinuities). In nearly all the surveys statistically significant correlations were reported between low soil resistivity and dowsing reactions. It was not clear whether the soil resistivity survey was conducted by a person blind to the dowsers’ responses. 

   Although Tromp found strong correlations between changes in magnetic field strength and dowsing zones, he did not conclude that there was a causal relationship between the two where field conditions were concerned. He suggested that dowsers might be sensitive to very low level infra-red radiation, since they could detect changes in soil resistivity although the accompanying magnetic field fluctuations were very small (producing gradients far smaller than those detected by dowsers in his laboratory). Unfortunately he did not present any experimental data to support this hypothesis. Tromp ruled out a psychic explanation since his dowsers could not predict  zones of disturbance (e.g. low soil resistivity) at a distance. Map dowsing tests he conducted with people claiming such ability were unsuccessful (Tromp, 1968). As no details were given, an evaluation of the methods and results is not possible. 

   Yves Rocard, professor of physics at the Ecole Normale in Paris, also studied the relation betweeen dowsing and electromagnetic radiation. Much of his research on dowsing is discussed in his book Le Signal du Sourcier (reviewed by Montgomery, 1964; Parsons, 1963; and Thouless, 1964). Only two very brief summaries seem to have appeared in English (Rocard in Barnothy, 1964; L’Huillier, 1968). In his experiments Rocard set up a wooden frame (50 cm by 100 cm) wrapped with 100 turns of fine wire. The frame was placed in a location with reportedly no stray magnetic gradients. The subjects were given a brief training period on how to hold the Y-rod and allowed to practise when they knew the current was on or off. Rocard reports that during the testing, every precaution was taken to prevent the dowser from knowing whether the experimenter turned the current on or off but gave few details. He concluded that a dowser could detect a changing artificial magnetic field of the order of 0.3 to 0.5 mO/m (approximately equivalent to 0.0003 to 0.0005 gauss per metre in air) at the level of the subject’s chest if the dowser were walking at a normal speed. Rocard claimed that a good dowser is never wrong when attempting to detect this signal as long as he is not overworked. He noted that smaller gradients could be detected if the dowser were walking faster or travelling in a vehicle as long as the change was at least 0.3 to 0.5 mO/sec (0.0003 to 0.0005 gauss per second). It was also found that the reaction of the dowser was more pronounced if two coils of wire were used in series. This gave the dowser a longer exposure to the field. Rocard noted that below 0.1 mO/sec (0.0001 gauss per second) detection was inaccurate. It was also found that gradients in excess of some uncertain amount produced ‘saturation’; presumably this means that the dowsers were not sensitive to gradients above this level. Rocard also noted that if magnets were attached to the forearms of the dowsers, no reaction was obtained, but if a similar non-magnetic object were used, the dowsers were still able to respond. Presumably no indication was given to the dowsers as to which were and were not magnetic. It was also observed that dowsers’ responses were much less clear with a pendulum than with a rod (although this contrasts with Tromp’s comments, it should be noted that Rocard’s subjects used a type of rod unlike those used by Tromp’s subjects). No indication is given as to the number of subjects Rocard tested; thus it is difficult to know whether the indicated range applies to most or only a few dowsers. 

   Rocard noted that water filtering through porous media in permeable layers next to clay layers might be expected to produce a magnetic gradient on the order of 0.1 mOe/m (0.0001 gauss per metre). 

   One of the most prolific American investigators of dowsing is Dr. Zaboj V. Harvalik, a retired professor of physics formerly at the University of Arkansas and a former adviser to U.S. Army’s Advanced Concepts Materials Agency. He is now a vice-president of The American Society of Dowsers (ASD). Nearly all his work has been published in The American Dowser, the quarterly publication of ASD (and has appeared in nearly every issue since 1970). The present writer does not know whether independent investigators have tried to replicate it. Much of this work was done with electromagnetic fields. He, too, has found that dowsers are sensitive to changes in magnetic field strength though not to absolute magnitude, but believes them to be much more sensitive than other investigators have indicated and that a fairly sensitive dowser can respond to a change of 1 X 10-6 gauss per second (Harvalik, 1970).

Later in this report he claimed that an average dowser could detect a change of 3 X 10-7 gauss, a skilled dowser 3 X 10-8 gauss, and an exceptional dowser 7 X 10-9 gauss (the actual gradient involved is not completely clear) and that he tested one subject, Mr. De Boer, who could detect changes of 2 X 10-10 gauss. He mentioned that he found the L-rods gave better results than the forked stick and were easier and more sensitive for inexperienced dowsers. Only final results are presented in many of his reports, and methods of statistical evaluation are not discussed. It is unknown whether double blind conditions were strictly observed and whether all normal sensory cues were eliminated. One of his reports (Harvalik, 1978) is notable for the amount of detail it contains; it is discussed further in the Physiological Studies section of this paper. 

   Harvalik also found that dowsers could detect and discern different radio frequencies and radioactive substances even with considerable shielding (Harvalik, 1973a; Harvalik and De Boer, 1976). As with many of his experiments, the level of control is uncertain, and replication by others is needed before conclusions can be drawn. 

   Duane Chadwick and Larry Jensen, electrical engineers from Utah State University, produced one of the most detailed reports of a preliminary investigation concerning magnetic fields and dowsing. In a series of experiments (Chadwick and Jensen, 1971), a number of subjects, most without previous dowsing experience, separately walked along several pre-assigned paths with dowsing rods (mainly L-rods). They were given a set of wooden blocks and asked to place a block at each location where they obtained a dowsing reaction. After the dowsers had traversed the path, a magnetic survey was carried out. 

   A statistical analysis was made to determine whether there was any patterning of the dowsers’ responses. Chadwick and Jensen found that on certain portions of the path, dowsers were much more likely to experience dowsing reactions. The probabilities of this patterning (more reactions in some areas than others) occurring by chance ranged from p = 0.06 to p < 0.0005. If this were a parapsychological experiment, one might conclude that a very strong stacking effect was observed. 

   Chadwick and Jensen gave a graphical representation of the relation between the dowsers’ responses and the magnetic field but did not present a full statistical evaluation of these data; so it is not clear whether the correlation would be statistically significant (though it well may be). In areas with a gradient of 0.5 gamma per foot (0.000016 gauss per metre), more reactions were obtained than when the gradient was less. 

   In some experiments an iron bar was buried along the test path and there was reportedly no visual indication of its presence. The iron bar produced a distinct magnetic anomaly. From the graphical data presented it seems unlikely that the number of dowsing reactions near the bar was due to chance. 

   In another experiment the subjects were given 30 wooden blocks and were asked to drop them wherever they felt like it while on an assigned path. The patterning of responses among the subjects was more consistent than would be expected by chance at the 10 per cent level. When compared with the magnetic survey, on the average there were as many reactions in areas with the gradient greater than 0.5 gamma per foot (0.000016 gauss per metre) as in cases with a smaller gradient. It appears that this method which requires some conscious involvement to achieve a dowsing response was not effective. The apparently unconscious movement of the dowsing rods seems to make for greater accuracy. 

   Chadwick and Jensen did present calculations to show that the expected change in the magnetic field due to an aquifer (an underground formation containing water) could be as high as 0.0043 gauss. From previous data it seems that a dowser might be able to detect this. However, Chadwick and Jensen did not conclude that dowsing was necessarily an efficacious method of locating underground water. They noted that no wells had been dug in their study, that the type of information actually used by the dowsers was undefined, and that the patterning of the dowsers’ responses was not necessarily due to magnetic anomalies. Although they did not conclude that dowsers were sensitive to magnetic anomalies, they did conclude that further research was warranted and recommended that extraterrestial radiation be monitored during testing, or that tests be conducted in an environment shielded from all extraneous magnetic influences. They also noted that it is not clear which (if any) magnetic field the dowser might be detecting (e.g. field at ground level, at head level, gradients in vertical or horizontal plane, etc.). 

   W. H. Jack, a parapsychology instructor at Franklin Pierce College in New Hampshire, experimented to determine whether subjects could use dowsing to detect a current flowing through a wire (Jack, 1978). The twelve subjects, members of an experimental parapsychology class, used L-rods to determine whether or not a current of 0.1 amp was flowing through an extension cord (no data were given as to the resulting magnetic field strength or gradient). The subjects were asked to report whether the current was on or off. Of 240 trials, there were 141 hits (p < 0.01). Jack indicated that the subjects were in familiar surroundings, in good rapport, and involved in the experimental design, but admitted that the study was not conducted double blind. The person recording whether power was on or off also recorded the dowsers’ responses—allowing the possibility of biassed recording errors. From the report, one might be given the impression that the subjects were using psi to obtain the correct results; even if there were no recording errors or other sensory leakage, there could have been an effect due to electro-magnetic radiation. The report does not show whether the intent was to investigate a psi phenomenon or a biophysical one. 

   Jack (1977) also conducted an experiment in which six rather inexperienced dowsers (college students) attempted to locate a vein of water previously dowsed by several more experienced ones. Twenty-six two-metre long intervals were marked with stakes along a road, and the subjects were asked to use L-rods to determine the previously selected interval. A majority vote was taken, and the group did pick the correct interval, p = 0.038. A definite effort was made to establish a realistic dowsing situation and psi conducive environment. The subjects were told that the experimenter planned to build a house and needed a well and were encouraged to visit the site when the well was to be dug. A picnic was held after the dowsing test. It appears that the test was not conducted double blind; the experimenter apparently knew the location of the pre-selected interval and was present during the test. It is also uncertain whether the dowsers were using psi, or reacting to some electromagnetic radiation, or some other stimulus. Overall, the result basically confirms the patterning of responses noted by Chadwick and Jensen. 

   Several experimental failures to support the electromagnetic hypothesis have been reported. 

   Foulkes (1971) attempted to replicate Rocard’s work with artificial magnetic fields. Coils of wire similar to his were set up. The dowser (who claimed such ability) was given a short series of learning trials in which he knew whether the current was on or off. Three runs of 25 trials were held with no indication given to the dowser whether the current was on or off. Only chance results were obtained. Unfortunately only one dowser was used in this study. No mention was made whether there were possible magnetic anomalies in the area of the testing. 

   Whitton and Cook (1978) also conducted two experiments attempting to determine whether subjects could detect the presence of weak magnetic fields. In the first, twenty-seven subjects, two believing themselves to be dowsers, were asked to determine whether current was flowing through a coil similar to that of Rocard’s (here alternating current was used). Each was allowed a preliminary learning trial conducted without the use of dowsing instruments, although the subjects were allowed to move around. They simply stated verbally whether the current was on or off. Only chance results were obtained. In the second experiment, eleven subjects, none of them professional dowsers, were asked to determine whether current was flowing through the coil of wire when it was placed in a known horizontal position beneath the floor of the room. In this case direct current was used. The subjects were given L-rods to use. Again they gave verbal reports. Here also only chance results were obtained. No mention was made as to whether there were possible magnetic anomalies at the test site.

   Balanovski and Taylor (1978) claim to have tested dowsers’ sensitivities to magnetic fields. They found that those tested were insensitive to fields of 100 gauss. Taylor (1980) reported that one dowser tested with 500 gauss was also not sensitive. No gradients were indicated in the reports, and no details were given as to testing procedure. Taylor and Balanovski (1979b) also tested a number of persons, including dowsers, for sensitivity to high-frequency low power level electromagnetic fields. The subjects sat close to an antenna while the power was randomly switched on or off. Between 10 and 60 trials per subject were conducted but they were apparently unable to tell whether the power was on or off. Taylor and Balanovski (1979a, c) conclude that dowsing is not possible because the level of sensitivity required is far greater than that they claim for human capability. 

   Much work has been done concerning the effects of electromagnetic radiation on living organisms; Barnothy (1964), Presman (1970), Persinger (1974), and Dubrov (1978) have summarized the findings. Except for work on dowsing, very little has been done to determine the effects on humans of very slight changes in magnetic fields. Some work in biophysics indicates that at times a small field has a greater effect on a living organism than a stronger field (Prcsman, 1970). There have been anecdotal reports of persons receiving radio broadcasts from the fillings in teeth; presumably the radiation involved is relatively low intensity. Wieske (1963) reported two cases of amazing auditory sensitivity to electric fields. One woman could even hear telephone conversations by listening to the wires! 

   Because of the wide range of findings reported as to the sensitivity of dowsers it is difficult to draw conclusions. Although there is positive evidence that humans do have some ability to detect weak electromagnetic fields, the results of Whitton and Cook, and Balanovski and Taylor challenge the conclusions of other investigators. It is far too early to conclude that this sensitivity can be used to detect underground water. 

   Further experiments appear justified and could have wide ranging implications. Work could be done to determine human thresholds of sensitivity to horizontal and vertical magnetic fields (ideally in a shielded environment to eliminate extraneous magnetic fields). The psychological state of the subjects might usefully be varied; perhaps relaxation would facilitate greater sensitivity. Any further work must use extremely tight controls to rule out alternative information sources. The results of such experiments might indicate unsuspected communication systems; if so, such knowledge would have useful applications.