Agricola (De Nat. Fos., p. 229-230) not only gives various localities of jet, but also records its relation to coal. As to the latter, he describes several occurrences, and describes the deposits as vena dilatata. Coal had come into considerable use all over Europe, particularly in England, long before Agricola's time; the oft-mentioned charter to mine sea-coal given to the Monks of Newbottle Abbey, near Preston, was dated 1210.
Amber was known to the Greeks by the name electrum, but whether the alloy of the same name took its name from the colour of amber or vice versa is uncertain. The gum is supposed to be referred to by Homer (Od. XV. 460), and Thales of Miletus (640-546 B.C.) is supposed to have first described its power of attraction. It is mentioned by many other Greek authors, Æschylus, Euripides, Aristotle, and others. The latter (De Mirabilibus, 81) records of the amber islands in the Adriatic, that the inhabitants tell the story that on these islands amber falls from poplar trees. "This, they say, resembles gum and hardens like stone, the story of the poets being that after Phaeton was struck by lightning his sisters turned to poplar trees and shed tears of amber." Theophrastus (53) says: "Amber is also a stone; it is dug out of the earth in Liguria and has, like the before-mentioned (lodestone), a power of attraction." Pliny (XXXVII., 11) gives a long account of both the substance, literature, and mythology on the subject. His view of its origin was: "Certainly amber is obtained from the islands of the Northern Ocean, and is called by the Germans glaesum. For this reason the Romans, when Germanicus Cæsar commanded in those parts, called one of them Glaesaria, which was known to the barbarians as Austeravia. Amber originates from gum discharged by a kind of pine tree, like gum from cherry and resin from the ordinary pine. It is liquid at first, and issues abundantly and hardens in time by cold, or by the sea when the rising tides carry off the fragments from the shores of those islands. Certainly it is thrown on the coasts, and is so light that it appears to roll in the water. Our forefathers believed that it was the juice of a tree, for they called it succinum. And that it belongs to a kind of pine tree is proved by the odour of the pine tree which it gives when rubbed, and that it burns when ignited like a pitch pine torch." The term amber is of Arabic origin—from Ambar—and this term was adopted by the Greeks after the Christian era. Agricola uses the Latin term succinum and (De Nat. Fos., p. 231-5) disputes the origin from tree gum, and contends for submarine bitumen springs.
[Pg 36][16] The statement in De Veteribus et Novis Metallis (p. 394) is as follows:—
"It came about by chance and accident that the silver mines were discovered at Freiberg in Meissen. By the river Sala, which is not unknown to Strabo, is Hala, which was once country, but is now a large town; the site, at any rate, even from Roman times was famous and renowned for its salt springs, for the possession of which the Hermunduri fought with the Chatti. When people carried the salt thence in wagons, as they now do straight through Meissen (Saxony) into Bohemia—which is lacking in that seasoning to-day no less than formerly—they saw galena in the wheel tracks, which had been uncovered by the torrents. This lead ore, since it was similar to that of Goslar, they put into their carts and carried to Goslar, for the same carriers were accustomed to carry lead from that city. And since much more silver was smelted from this galena than from that of Goslar, certain miners betook themselves to that part of Meissen in which is now situated Freiberg, a great and wealthy town; and we are told by consistent stories and general report that they grew rich out of the mines." Agricola places the discovery of the mines at Freiberg at about 1170. See [Note 11, p. 5].
[17] Diodorus Siculus (V., 35). "These places being covered with woods, it is said that in ancient times these mountains were set on fire by shepherds, and continued burning for many days, and parched the earth, so that an abundance of silver ore was melted, and the metal flowed in streams of pure silver like a river." Aristotle, nearly three centuries before Diodorus, mentions this same story (De Mirabilibus, 87): "They say that in Ibernia the woods were set on fire by certain shepherds, and the earth thus heated, the country visibly flowed silver; and when some time later there were earthquakes, and the earth burst asunder at different places, a large amount of silver was collected." As the works of Posidonius are lost, it is probable that Agricola was quoting from Strabo (III., 2, 9), who says, in describing Spain: "Posidonius, in praising the amount and excellence of the metals, cannot refrain from his accustomed rhetoric, and becomes quite enthusiastic in exaggeration. He tells us we are not to disbelieve the fable that formerly the forests having been set on fire, the earth, which was loaded with silver and gold, melted and threw up these metals to the surface, for inasmuch as every mountain and wooded hill seemed to be heaped up with money by a lavish fortune." (Hamilton's Trans. I., p. 220). Or he may have been quoting from the Deipnosophistae of Athenaeus (VI.), where Posidonius is quoted: "And the mountains ... when once the woods upon them had caught fire, spontaneously ran with liquid silver."
[Pg 37][18] Lucretius, De Rerum Natura V. 1241.
[19] Agricola's account of this event in De Veteribus et Novis Metallis is as follows (p. 393): "Now veins are not always first disclosed by the hand and labour of man, nor has art always demonstrated them; sometimes they have been disclosed rather by chance or by good fortune. I will explain briefly what has been written upon this matter in history, what miners tell us, and what has occurred in our times. Thus the mines at Goslar are said to have been found in the following way. A certain noble, whose name is not recorded, tied his horse, which was named Ramelus, to the branch of a tree which grew on the mountain. This horse, pawing the earth with its hoofs, which were iron shod, and thus turning it over, uncovered a hidden vein of lead, not unlike the winged Pegasus, who in the legend of the poets opened a spring when he beat the rock with his hoof. So just as that spring is named Hippocrene after that horse, so our ancestors named the mountain Rammelsberg. Whereas the perennial water spring of the poets would long ago have dried up, the vein even to-day exists, and supplies an abundant amount of excellent lead. That a horse can have opened a vein will seem credible to anyone who reflects in how many ways the signs of veins are shown by chance, all of which are explained in my work De Re Metallica. Therefore, here we will believe the story, both because it may happen that a horse may disclose a vein, and because the name of the mountain agrees with the story." Agricola places the discovery of Goslar in the Hartz at prior to 936. See [Note 11, p. 5].
[20] Fragmenta. The glossary gives "Geschube." This term is defined in the Bergwerks' Lexicon (Chemnitz, 1743, p. 250) as the pieces of stone, especially tin-stone, broken from the vein and washed out by the water—the croppings.
[Pg 38][21] So 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-VIII.), 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 (divinations) 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 Divinatoire," Paris, 1845; L. Figuier, "Histoire du Merveilleux dans les temps moderne II.", Paris, 1860; 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.