hay, which is called the cordum, is cut with scythes in the month of
September. Therefore in places where the grass has a dampness that is not congealed into frost, there is a vein beneath ; also if the exhalation be excessively
hot, the soil will produce only small and pale-coloured plants. Lastly, there
are trees whose foliage in spring-time has a bluish or leaden tint, the upper
branches more especially being tinged with black or with any other unnatural
colour, the trunks cleft in two, and the branches black or discoloured.
These phenomena are caused by the intensely hot and dry exhalations
which do not spare even the roots, but scorching them, render the trees
sickly ; wherefore the wind will more frequently uproot trees of this kind
than any others. Verily the veins do emit this exhalation. Therefore, in a
place where there is a multitude of trees, if a long row of them at an unusual
time lose their verdure and become black or discoloured, and frequently fall
by the violence of the wind, beneath this spot there is a vein. Likewise
along a course where a vein extends, there grows a certain herb or fungus
which is absent from the adjacent space, or sometimes even from the neighbourhood of the veins. By these signs of Nature a vein can be discovered.
There are many great contentions between miners concerning the forked
twig21, for some say that it is of the greatest use in discovering veins, and
others deny it. Some of those who manipulate and use the twig, first cut
a fork from a hazel bush with a knife, for this bush they consider more
efficacious than any other for revealing the veins, especially if the hazel
slSo far as we are able to discover, this is the first published description of the divining
rod as applied to minerals or water. Like Agricola, many authors have sought to find its
origin among the Ancients. The magic rods of Moses and Homer, especially the rod with
which the former struck the rock at Horeb, the rod described by Ctesias (died 398 b.c.) which
attracted gold and silver, and the virgula divina of the Romans have all been called up for
proof. It is true that the Romans are responsible for the name virgula divina, " divining
rod," but this rod was used for taking auguries by casting bits of wood (Cicero, De
Divinatione). Despite all this, while the ancient naturalists all give detailed directions for
finding water, none mention anything akin to the divining rod of the Middle Ages. It is
also worth noting that the Monk Theophilus in the 12th Century also gives a detailed
description of how to find water, but makes no mention of the rod. There are two authorities sometimes cited as prior to Agricola, the first being Basil Valentine in his " Last Will
and Testament" (xxiv-vin.), and while there may be some reason (see Appendix) for accepting
the authenticity of the " Triumphal Chariot of Antimony " by this author, as dating about
1500, there can be little doubt that the " Last Will and Testament " was spurious and dated
about 50 years after Agricola. Paracelsus (De Natura Rerum ix.), says : " These (divina" tions) are vain and misleading, and among the first of them are divining rods, which have
" deceived many miners. If they once point rightly they deceive ten or twenty times."
In his De Origine Morborum Invisibilium (Book I.) he adds that the " faith turns the rod."
These works were no doubt written prior to De Re Metallica—Paracelsus died in 1541—
but they were not published until some time afterward. Those interested in the strange
persistence of this superstition down to the present day—and the files of the patent offices
of the world are full of it—will find the subject exhaustively discussed in M. E. Chevreul's
" De la Baguette Didnatoire," Paris, 1845 ; L. Figuier, " Histoire du Merveilleux dans les
temps moderne II.", Paris, i860 ; W. F. Barrett, Proceedings of the Society of Psychical
Research, part 32, 1897, and 38, 1900 ; R. W. Raymond, American Inst, of Mining Engineers, 1883, p. 411. Of the descriptions by those who believed in it there is none better
than that of William Pryce (Mineralogia Cornubiensis, London, 1778, pp. 113-123), who
devotes much pains to a refutation of Agricola. When we consider that a century later than
Agricola such an advanced mind as Robert Boyle (1626-1691), the founder of the Royal
Society, was convinced of the genuineness of the divining rod, one is more impressed with
the clarity of Agricola's vision. In fact, there were few indeed, down to the 19th Century,
who did not believe implicitly in the effectiveness of this instrument, and while science has
long since abandoned it, not a year passes but some new manifestation of its hold on the
popular mind breaks out.
