THE divining-rod, spoken of by the Romans as "virgula divina," and mentioned by Cicero and by Tacitus, was a different thing altogether from the modern forked twig of the water-finder, and seems to be of immemorial antiquity. Its use in "divination" was similar to that practised with a ring or a sieve suspended by a string. When the rod is thrown into the air and falls to the ground, or when the suspended object is set moving, it eventually comes to rest, and when thus at rest must point in one particular direction. It was supposed that gods or spirits invoked at the moment guided the movement and final position of rest, so as to make the divining-rod or ring or sieve point to buried treasure, to an undetected murderer, or to a witch or wizard who had used magic arts to injure the person seeking its aid. Bits of stick are so used at the present day by some savage races. The notion leading to its use is the same as that which has led to augury by inspection of an animal's entrails, by the flight of birds, and other such varying appearances. The notion is that an unseen protective power will, when properly invoked, interfere with the blindly varying thing and make it vary so as to give indications either of hidden objects or of future events. The unseen power which thus revealed itself was primitively supposed to be that of a god or a spirit, but later the augur or intermediary who worked the "show" acquired exclusive importance and arrogated to himself mysterious powers. The same transference of importance has come about in the case of the modern hazel-twig and the "douser," who now claims to "divine" without its aid.

The tossing of a halfpenny to decide as to alternative courses of action, still almost universally prevalent in this country, is in origin (and largely in actual practice) an appeal to supernatural powers to give an indication by interference with the natural fall of the coin, as to which of the alternative courses is the more favourable to the interests of the individual who tosses the coin or agrees to follow its decision if tossed by someone else. "Heads I go; tails I stay where I am." Of a like nature is the drawing of lots, and so are a number of similar practices originally devised for the purpose of obtaining guidance from supernatural sources. Some of them have survived without any associated superstition, and are commonly used at the present day merely in order to obtain an impersonal decision as to which of two or more claimants is to enjoy a certain privilege or exemption, as, for instance, when a coin is tossed to decide as to which side of the river at the start shall be occupied by competitors in a boat race, or which shall have choice of innings in a cricket match, or as when lots are drawn to determine who shall enjoy exemption from military service. But even in these cases there are large numbers of men and women who believe that some mysterious power which could possibly be won over to their side, or else what they call "a special providence," determines the issue. There are, I need hardly say, no facts which justify the belief in any such interruption of the orderly course of nature.

The forked twig (virgula furcata of the alchemists) used by water-finders has another significance and history. The forked twig is held, one branch in one hand and the other branch in the other hand, by the explorer. After a time, as the explorer walks along, the twig suddenly, and even vigorously, "plunges" or "ducks" as he holds it. It seems to do so "of its own accord." The old English word "douse" signifies ducking, dipping, or plunging. The forked twig "douses." Hence the persons who use it are called "dousers." The belief is widespread that this dousing or plunging of the forked twig is caused by the presence of a vein of metallic ore in the ground, or in other cases by the presence of subterranean water. It is interesting to ascertain what grounds there are for this belief.

The dousing-rod or twig is first mentioned in the fifteenth century by a writer on alchemy (Basil Valentine), and in 1546 by Agricola (De re metallica), who says it must be either of willow or hazel, and describes its use in the discovery of metalliferous veins and subterranean water. The purely fantastic belief on which its use was based was part of the doctrine of "sympathies." It was supposed that the branches of certain plants were drawn to certain "sympathetic" metals in the earth beneath them—a supposition suggested by the downward growth or "weeping" of the branches of trees and bushes in some cases. By the Germans the forked twig used in searching for metals or water was called "Schlagruthe," which has the same meaning as "dousing" or "plunging" or "striking rod." It was introduced into England by German miners who were employed in the time of Queen Elizabeth by merchant venturers in working the Cornish mines—and it has remained with us ever since—though one hears little at the present day of its use in searching for metalliferous deposits, and more about the supposed wonderful results obtained with its aid by professional water-finders.

We have to distinguish the facts established in regard to "the dousing-twig" from the inferences and suppositions based upon those facts by credulous people. There is no room for doubt that when the forked twig, in shape like a letter Y upside down, is held by a more or less nervous but perfectly honest person who takes the matter very seriously, and holds firmly one branch of the fork in one hand and the other in the other hand, the fingers well round it so as to bring it against the palm of the hand, a strange thing happens after some minutes. The twig seems to the person holding it to give a sudden movement as though drawn downwards. If he or she is walking along, intently awaiting this movement, and believing that it will be caused by some subterranean attraction, the effect is, naturally enough, startling. It occurs more readily with some persons than with others. What is the explanation of it? There is no necessity for supposing that it is due to any mysterious attraction by hidden water or metal. It has been clearly shown that it is due to fatigue of the muscles which are employed in keeping the hands and fingers in position. The muscles in use suddenly relax, and the hands turn to a new pose—one of rest—and with them the forked twig. In most persons attention and control are sufficiently active to prevent this sudden relaxation of the muscles. But those who are liable to mental absorption in the strange procedure, and are apt to become half-dazed by the solemn sort of "rite" in which they are engaged, find their tired hands (tired, though they are unconscious of it) suddenly turning, and the twig "ducking" downwards in a way which they can neither explain nor control. Such persons are the honest, self-deceived "dousers," who are, and have been, sufficiently numerous to establish a belief in the existence of a mysterious agency causing the twig to "duck." No doubt originally, with complete innocence and honesty, this mysterious agency was believed to be a sort of magnetic attraction due to a sympathy between the twig and subterranean metal. In later days, without any attempt to give a reason for the change, the same class of people have believed that it was water far below the surface of the earth which was the cause of the attraction, and consequent ducking or dousing of the twig.

Let us assume for a moment that the facts are as I have stated, and that the honest "douser" merely finds his forked twig dousing or ducking because his hands are tired by keeping in one position. Then it is evident that no harm would be done, but rather a useful decision leading to action would be determined, by the belief that concealed metal was the cause of the "ducking." Digging must be commenced somewhere, and the dousing-rod would only be tried on likely ground, so that, often, the thing sought for (whether metal or water) would be found after prolonged excavation at the spot indicated by the douser, or near it. If the digging were a failure, the believers in the dousing-rod would say that they had not been able to dig deep enough, or that some hostile agency had intervened and misled the "douser," or that he was in poor health, and so "worked" badly. The successes are remembered and the failures forgotten. So the belief in the dousing-twig as a real guide to subterranean metal and water has been maintained, and all the more securely because there have been, and doubtless are still, many honest, innocent country people who truly believe that they possess an exceptional and mysterious gift in being able to experience the curious ducking action of the twig when they walk with it in their hands in quest of this or that.

In the seventeenth century the dousing-twig was used as a guide in all sorts of quests, for instance, in searching for hidden treasure and in tracking criminals! In our own times it is chiefly known through its use by professional water-finders. There is no doubt that some of these gentry are dishonest. They are not the credulous rustics to whom the dousing-twig owes its long popularity. They are often clever and expert judges of the indications by form of the land, lie of geological strata, and distribution of vegetation, as to the subterranean water which is so abundant in this country. They make a pretence of using the douser's twig, in order to obtain employment from landowners in search of a likely spot for sinking a well, since it is the fact that many people prefer to be guided by a sort of magician who uses a supposed mysterious occult agency rather than to employ the honest and perhaps less acute geologist who avowedly proceeds in his search for water by making use of ascertained facts as to the structure and character of the subsoil and deeper strata of the district in which his services are called for.

The believers in the connexion of the movement of the douser's rod and the existence of concealed metal or water, have of late years started the theory that the twig itself is of no value in the "experiment." Certain dousers have declared that they can work just as well without it, and that it is not the rod or twig but they themselves who are sensitive to concealed water or metal. They state that they feel a peculiar "sinking" in the pit of the stomach, also a nervous tremor, and that their hands move spasmodically, causing the rod to move, and they attribute this to an influence on the human body of "vibrations" or possibly "electricity" from the concealed metal or water. This is ingenious enough; it shifts the seat of mysterious action from the simple twig to the much more complex human body, and accepts to a certain extent what I have above stated as to the nervous condition of the douser and the fatigue of the hands.

Others, who have lately discussed the subject, suggest that the douser is affected not by any known kind of physical vibrations, but by some mysterious emanation from the concealed metals or water similar to that which they (without any sufficient evidence) assume to pass from one human being to another over long distances, causing what has been called "second-sight," "thought-reading," and (in order to give an air of scientific importance to it) "telepathy." This may seem satisfactory to some people, but it is plainly a case of attempting to explain a little-known thing by reference to a still less known thing—what is called "ignotum per ignotius." Sir W. F. Barrett, of Dublin, has lately written on this subject, and very rightly says that the real question to be decided in the first instance is whether the modern "water-finders," who profess to be guided by occult influences, whatever the nature of those influences may be, are more successful in discovering water than those who seek for it by the use of the known natural indications of its presence; and, further,—and this seems to me to be the most important consideration,—whether, taking into account all the "experiments" made by the occultist water-finders, both the successful and the unsuccessful, the proportion of successes is greater than might be expected as a matter of chance and the use of common intelligence.

That is, in fact, the interesting point about the persistent belief in the "magical" powers of water-finders. It is one of several more or less traditional beliefs which depend on coincidence. The belief in birth-marks is of this nature. A lizard drops from the ceiling of her room on to a woman. A few weeks afterwards she bears a child which has a mark upon its breast more or less "resembling" a lizard. Some people believe that the mark on the child is caused by what is called "a maternal impression," the influence on the mother's mind of the scare caused by the lizard being expressed in the mark on the child's body. To form a conclusion as to the truth of this explanation we require to know what proportion of mothers in a given population have been startled by lizards, what proportion of children are born with marks on them more or less "resembling" a lizard (there is much significance in the "more or less"), and whether there are more children born with a lizard-like mark on the body from mothers who have been frightened shortly before the child's birth by a lizard, than from mothers who have not been thus frightened. The inquiry is not an easy one. The same question of coincidence applies to water-finding. Taking several thousand attempts to find water we must ask, "Is the attempt unsuccessful in a larger percentage of trials in the case of those who do not follow the indications of a dousing-rod than in the case of those who make use of it?" Sir W. F. Barrett admits the difficulty of getting at satisfactory statistics in the matter; but is inclined to think the dousers are the more successful, and so entertains a theory of mysterious agency to account for their success. My own impression is that in difficult cases of search for water dousers are as frequently unsuccessful as non-dousers.

It is true we cannot get proper returns of all cases of success and failure. But in this matter of "water-finding" we can make use of "experiment," a thing which is not so easy in regard to birth-marks—though it is related that the patriarch Jacob made an experiment of this character with his pealed stakes. Experiments have lately been made with dousers or water-diviners to test their powers. These experiments have been carried out both in Paris and in the South of England. They are unfavourable to the pretensions of the diviners.

It is very difficult to perform under perfectly fair conditions a number of experiments sufficiently large to enable us to arrive at a demonstration of the truth in this matter. Some thousand "dousers" should be put to the test under proper conditions and guarantees, and the percentage of failures and successes carefully recorded. This has not been done, although "dousers" have often been tested and found to be unable to discover subterranean water known to be present, or else have given erroneous indications. If you prove some one individual "douser" to be an impostor, or else self-deluded—the reply by those who believe in the existence of the occult power attributed to dousers is, naturally enough, that though this individual was an impostor, or incapable, yet that does not prove that all other individuals who claim to possess certain peculiar powers in the discovery of water are so. All that can be done is to challenge any douser to come forward and establish, in the presence of a competent tribunal of experts, that he can indicate in a given area the whereabouts of subterranean water already known to the committee but not possibly known beforehand to the douser.

This experiment was made a year or two ago near Guildford by a committee of water engineers and geologists, and also by a similar committee in Paris. Only a dozen or two of the water-finding dousers came forward and submitted to be thus tested, and they entirely failed to show any special capacity for discovering water. They failed signally. But then the believers may, of course, retort that the really gifted superior dousers had refused to have anything to do with the inquiry, and that "their withers are unwrung." The same kind of test was some years ago made with the so-called "spiritualist mediums." A banknote for £1000 was placed in a very carefully sealed envelope, and deposited in a safe in a bank. Its owner advertised his offer to present the note to any spiritualists who would correctly state the number of the note. The offer remained open for some years, but the spiritualists were unable to gain information about this very simple matter by their methods of consulting supposed "spirits," and the note was never claimed. Of course, some of those who believe in spiritualism, maintain that the genuine "mediums," for some reason not altogether clear, refused to make the attempt to discover the number. Others put forward the view that the "spirits" took offence at the proposed test, and refused to reveal the number. Others, again, took the line that this was just one of the few things about which "spirits" are unable to communicate with mortals, or are forbidden by superior order to reveal.

It is accordingly fairly obvious that it is not of much use to take the trouble to expose the falsity of the pretensions of any isolated specimen of a douser or of a spirit medium. However that may be, some years ago, when I was staying in an ancient castle in the North of England, my hostess procured the attendance of a youth who had a great reputation as a douser, in order that I might test his pretensions. The youth arrived with his father, and had half a dozen Y-shaped hazel twigs ready for use. The party staying in the castle met him on the terrace, a broad gravel walk which surrounded the battlements. I asked him to walk round the castle and mark in our presence the spots at which his twig indicated the presence of subterranean water. The circuit was somewhat less than a quarter of a mile, and he indicated eleven spots. We placed obvious marks at each of these spots. I then took him into the castle and, aided by a friend, carefully blindfolded him with pads of cotton-wool over each orbit and a large silk handkerchief. We then led him out by a circuitous route on to the terrace and asked him to try again to indicate the spots which he had just discovered. He walked along as before and stopped at several spots, saying that his twig indicated water where he stood. He also made futile efforts by turning and throwing back his head, to catch a glimpse of some of the marks we had placed at the spots previously indicated by him. But the pads of cotton-wool effectually prevented him from seeing anything. In no case (as a large party of onlookers testified) were the spots indicated on his second circuit identical with, or even near to, those marked in the first circuit. His father said he was "upset" by the blindfolding. We then removed the bandage, and took him into a large courtyard beneath and across which from one corner to another a large subterranean conduit ran. We had arranged that the water should be running in abundance through this conduit. We told him that such a subterranean channel existed. He was left free and undisturbed, and his eyes were not bandaged. But he failed to discover the conduit altogether, although he crossed it several times; and he ended by declaring that his twig indicated subterranean water at a spot remote from the conduit, where some large vats stood for the purpose of storing rain-water! All this, of course, tended to prove the incompetence of the youth as a douser, and to make it probable that such successes as he had obtained elsewhere (and my hostess stated that they were very numerous and remarkable, and vouched for by members of her own family) were due to imposture.

But a single case like this does not bring one very far on the way to deciding the question as to whether there are persons who are genuinely and successfully guided to the discovery of subterranean water by strange sensations and by spasmodic movements of their limbs or of hazel-twigs held in the hands, due (as they declare) to an obscure influence which emanates from subterranean water and from buried metal. The fact is that we have in the belief in the guidance of the douser by occult influences a troublesome case of the fallacy in reasoning expressed by the words, "post hoc ergo propter hoc," or, to put it in English, "after this, therefore caused by this." Primitive man found that this mode of forming a conclusion very often led to a correct discovery of the connexion between two events, and he adopted it as a ready method of guidance, although it was frequently fallacious. It has taken ages, literally ages, to make people discard this mode of arriving at a conclusion in serious matters, and it is still usual in less vital affairs. To show that B followed upon the occurrence of A, even once, is, of course, a proper and useful way of forming a guess or a suggestion as to the cause of B, but still more is your guess legitimate if the sequence has occurred several times in your experience. But it is only a guess: a conclusion must not be accepted on that basis, although lazy and hasty people do adopt such conclusions. You must find out the details of the nature of A and also of B, and if possible how the one is connected with the other. And if you cannot do that you can still establish your conclusion and confirm your guess by showing that B invariably follows upon A, or that (in a long experience) only when A has been present, and never when A has not been present, has B occurred. If you cannot prove the truth of your guess by this experimental demonstration of the exclusion of other causes than A or by the experimental demonstration of the invariable occurrence of B after A has occurred, then you have to seek for evidence of a real connexion between A and B, though not an invariable one, by collecting a vast number of instances of the occurrence of B and finding out whether A has preceded it in such a large proportion of cases (as compared with those in which B has occurred without the previous occurrence of A) that the cases in which B follows A cannot be considered as accidental, but indicate a real causal relation of A to B.

This is always a difficult undertaking, whether we start with the guess that B is caused by A or that it is not caused by A. In the case of water-finding, water is found at depths of 30 feet to 100 feet and more below the surface by engineers without the aid of "dousers" every day, and this is so frequent and regular a proceeding that the percentage of cases in which dousers find water, that is to say in which B—the discovery of water—follows A (A being the employment of a supposed sensitive douser with or without his twig) does not—so far as I am able to judge without strict statistical evidence—exceed the percentage of successes in searching and digging for water by ordinary intelligent men without the introduction of A.