Chapter VII: Conclusion: If we strip his theory of the necessary influence of the

state of knowledge of his time, and of his own deep classical learning, we find two propositions original with Agricola, which still to-day are fundamentals:

(1) That ore channels were of origin subsequent to their containing rocks; (2) That ores were deposited from solutions circulating in these openings. A scientist's work must be judged by the advancement he gave to his science, and with this gauge one can say unhesitatingly that the theory which we have set out above represents a much greater step from what had gone before than that of almost any single observer since. Moreover, apart from any tangible proposition laid down, the deduction of these views from actual observation instead of from fruitless speculation was a contribution to the very foundation of natural science. Agricola was wrong in attributing the creation of ore channels to erosion alone, and it was not until Von Oppel (_Anleitung zur Markscheidekunst_, Dresden, 1749 and other essays), two centuries after Agricola, that the positive proposition that ore channels were due to fissuring was brought forward. Von Oppel, however, in neglecting channels due to erosion (and in this term we include solution) was not altogether sound. Nor was it until late in the 18th century that the filling of ore channels by deposition from solutions was generally accepted. In the meantime, Agricola's successors in the study of ore deposits exhibited positive retrogression from the true fundamentals advocated by him. Gesner, Utman, Meier, Lohneys, Barba, Roessler, Becher, Stahl, Henckel, and Zimmerman, all fail to grasp the double essentials. Other writers of this period often enough merely quote Agricola, some not even acknowledging the source, as, for instance, Pryce (_Mineralogia Cornubiensis_, London, 1778) and Williams (Natural History of the Mineral Kingdom, London, 1789). After Von Oppel, the two fundamental principles mentioned were generally accepted, but then arose the complicated and acrimonious discussion of the origin of solutions, and nothing in Agricola's view was so absurd as Werner's contention (_Neue Theorie von der Entstehung der Gaenge_, Freiberg, 1791) of the universal chemical deluge which penetrated fissures open at the surface. While it is not the purpose of these notes to pursue the history of these subjects subsequent to the author's time, it is due to him and to the current beliefs as to the history of the theory of ore deposits, to call the attention of students to the perverse representation of Agricola's views by Werner (op. cit.) upon which most writers have apparently relied. Why this author should be (as, for instance, by Posepny, Amer. Inst. Mining Engineers, 1901) so generally considered the father of our modern theory, can only be explained by a general lack of knowledge of the work of previous writers on ore deposition. Not one of the propositions original with Werner still holds good, while his rejection of the origin of solutions within the earth itself halted the march of advance in thought on these subjects for half a century. It is our hope to discuss exhaustively at some future time the development of the history of this, one of the most far-reaching of geologic hypotheses.

[2] The Latin _vena_, "vein," is also used by the author for ore; hence this descriptive warning as to its intended double use.

[3] The endeavour to discover the origin of the compass with the Chinese, Arabs, or other Orientals having now generally ceased, together with the idea that the knowledge of the lodestone involved any acquaintance with the compass, it is permissible to take a rational view of the subject. The lodestone was well known even before Plato and Aristotle, and is described by Theophrastus (see Note 10, p. 115.) The first authentic and specific mention of the compass appears to be by Alexander Neckam (an Englishman who died in 1217), in his works _De Utensilibus_ and _De Naturis Rerum_. The first tangible description of the instrument was in a letter to Petrus Peregrinus de Maricourt, written in 1269, a translation of which was published by Sir Sylvanus Thompson (London, 1902). His circle was divided into four quadrants and these quarters divided into 90 degrees each. The first mention of a compass in connection with mines so far as we know is in the _Nuetzlich Bergbuechlin_, a review of which will be found in Appendix B. This book, which dates from 1500, gives a compass much like the one described above by Agricola. It is divided in like manner into two halves of 12 divisions each. The four cardinal points being marked _Mitternacht_, _Morgen_, _Mittag_, and _Abend_. Thus the directions read were referred to as II. after midnight, etc. According to Joseph Carne (Trans. Roy. Geol. Socy. of Cornwall, Vol. II, 1814), the Cornish miners formerly referred to North-South veins as 12 o'clock veins; South-East North-West veins as 9 o'clock veins, etc.

[4] _Crudariis._ Pliny (XXXIII., 31), says:--"_Argenti vena in summo reperta crudaria appellatur._" "Silver veins discovered at the surface are called _crudaria._" The German translator of Agricola uses the term _sylber gang_--silver vein, obviously misunderstanding the author's meaning.

[5] It might be considered that the term "outcrop" could be used for "head," but it will be noticed that a _vena dilatata_ would thus be stated to have no outcrop.

[6] It is possible that "veinlets" would be preferred by purists, but the word "stringer" has become fixed in the nomenclature of miners and we have adopted it. The old English term was "stringe," and appears in Edward Manlove's "Rhymed Chronicle," London, 1653; Pryce's, _Mineralogia Cornubiensis_, London, 1778, pp. 103 and 329; Mawe's "Mineralogy of Devonshire," London, 1802, p. 210, etc., etc.

[7] _Subdialis._ "In the open air." The Glossary gives the meaning as _Ein tag klufft oder tag gehenge_--a surface stringer.

[8] The following from Chapter IV of the _Nuetzlich Bergbuechlin_ (see Appendix B) may indicate the source of the theory which Agricola here discards:--"As to those veins which are most profitable to work, it must be remarked that the most suitable location for the vein is on the slope of the mountain facing south, so its strike is from VII or VI east to VI or VII west. According to the above-mentioned directions, the outcrop of the whole vein should face north, its _gesteins ausgang_ toward the east, its hangingwall toward the south, and its footwall toward the north, for in such mountains and veins the influence of the planets is conveniently received to prepare the matter out of which the silver is to be made or formed.... The other strikes of veins from between east and south to the region between west and north are esteemed more or less valuable, according to whether they are nearer or further away from the above-mentioned strikes, but with the same hangingwall, footwall, and outcrops. But the veins having their strike from north to south, their hangingwall toward the west, their footwall and their outcrops toward the east, are better to work than veins which extend from south to north, whose hangingwalls are toward the east, and footwalls and outcrops toward the west. Although the latter veins sometimes yield solid and good silver ore, still it is not sure and certain, because the whole mineral force is completely scattered and dispersed through the outcrop, etc."

[9] The names in the Latin are given as _Donum Divinum_--"God's Gift," and _Coelestis Exercitus_--"Heavenly Host." The names given in the text are from the German Translation. The former of these mines was located in the valley of Joachim, where Agricola spent many years as the town physician at Joachimsthal. It is of further interest, as Agricola obtained an income from it as a shareholder. He gives the history of the mine (_De Veteribus et Novis Metallis_, Book I.), as follows:--"The mines at Abertham were discovered, partly by chance, partly by science. In the eleventh year of Charles V. (1530), on the 18th of February, a poor miner, but one skilled in the art of mining, dwelt in the middle of the forest in a solitary hut, and there tended the cattle of his employer. While digging a little trench in which to store milk, he opened a vein. At once he washed some in a bowl and saw particles of the purest silver settled at the bottom. Overcome with joy he informed his employer, and went to the _Bergmeister_ and petitioned that official to give him a head mining lease, which in the language of our people he called _Gottsgaab_. Then he proceeded to dig the vein, and found more fragments of silver, and the miners were inspired with great hopes as to the richness of the vein. Although such hopes were not frustrated, still a whole year was spent before they received any profits from the mine; whereby many became discouraged and did not persevere in paying expenses, but sold their shares in the mine; and for this reason, when at last an abundance of silver was being drawn out, a great change had taken place in the ownership of the mine; nay, even the first finder of the vein was not in possession of any share in it, and had spent nearly all the money which he had obtained from the selling of his shares. Then this mine yielded such a quantity of pure silver as no other mine that has existed within our own or our fathers' memories, with the exception of the St. George at Schneeberg. We, as a shareholder, through the goodness of God, have enjoyed the proceeds of this 'God's Gift' since the very time when the mine began first to bestow such riches." Later on in the same book he gives the following further information with regard to these mines:--"Now if all the individual mines which have proved fruitful in our own times are weighed in the balance, the one at Annaberg, which is known as the _Himmelsch hoz_, surpasses all others. For the value of the silver which has been dug out has been estimated at 420,000 Rhenish gulden. Next to this comes the lead mine in Joachimsthal, whose name is the _Sternen_, from which as much silver has been dug as would be equivalent to 350,000 Rhenish gulden; from the Gottsgaab at Abertham, explained before, the equivalent of 300,000. But far before all others within our fathers' memory stands the St. George of Schneeberg, whose silver has been estimated as being equal to two million Rhenish gulden." A Rhenish gulden was about 6.9 shillings, or, say, $1.66. However, the ratio value of silver to gold at this period was about 11.5 to one, or in other words an ounce of silver was worth about a gulden, so that, for purposes of rough calculation, one might say that the silver product mentioned in gulden is practically of the same number of ounces of silver. Moreover, it must be remembered that the purchasing power of money was vastly greater then.

[10] The following passage occurs in the _Nuetzlich Bergbuechlin_ (Chap. V.), which is interesting on account of the great similarity to Agricola's quotation:--"The best position of the stream is when it has a cliff beside it on the north and level ground on the south, but its current should be from east to west--that is the most suitable. The next best after this is from west to east, with the same position of the rocks as already stated. The third in order is when the stream flows from north to south with rocks toward the east, but the worst flow of water for the preparation of gold is from south to north if a rock or hill rises toward the west." Calbus was probably the author of this booklet.

[11] Albertus Magnus.