De Re Metallica.

by Georgius Agricola.

PREFACE.

There are three objectives in translation of works of this character: to give a faithful, literal translation of the author's statements; to give these in a manner which will interest the reader; and to preserve, so far as is possible, the style of the original text. The task has been doubly difficult in this work because, in using Latin, the author availed himself of a medium which had ceased to expand a thousand years before his subject had in many particulars come into being; in consequence he was in difficulties with a large number of ideas for which there were no corresponding words in the vocabulary at his command, and instead of adopting into the text his native German terms, he coined several hundred Latin expressions to answer his needs. It is upon this rock that most former attempts at translation have been wrecked. Except for a very small number, we believe we have been able to discover the intended meaning of such expressions from a study of the context, a.s.sisted by a very incomplete glossary prepared by the author himself, and by an exhaustive investigation into the literature of these subjects during the sixteenth and seventeenth centuries. That discovery in this particular has been only gradual and obtained after much labour, may be indicated by the fact that the entire text has been re-typewritten three times since the original, and some parts more often; and further, that the printer's proof has been thrice revised. We have found some English equivalent, more or less satisfactory, for practically all such terms, except those of weights, the varieties of veins, and a few minerals. In the matter of weights we have introduced the original Latin, because it is impossible to give true equivalents and avoid the fractions of reduction; and further, as explained in the Appendix on Weights it is impossible to say in many cases what scale the Author had in mind. The English nomenclature to be adopted has given great difficulty, for various reasons; among them, that many methods and processes described have never been practised in English-speaking mining communities, and so had no representatives in our vocabulary, and we considered the introduction of German terms undesirable; other methods and processes have become obsolete and their descriptive terms with them, yet we wished to avoid the introduction of obsolete or unusual English; but of the greatest importance of all has been the necessity to avoid rigorously such modern technical terms as would imply a greater scientific understanding than the period possessed.

Agricola's Latin, while mostly free from mediaeval corruption, is somewhat tainted with German construction. Moreover some portions have not the continuous flow of sustained thought which others display, but the fact that the writing of the work extended over a period of twenty years, sufficiently explains the considerable variation in style. The technical descriptions in the later books often take the form of House-that-Jack-built sentences which have had to be at least partially broken up and the subject occasionally re-introduced. Ambiguities were also sometimes found which it was necessary to carry on into the translation. Despite these criticisms we must, however, emphasize that Agricola was infinitely clearer in his style than his contemporaries upon such subjects, or for that matter than his successors in almost any language for a couple of centuries. All of the ill.u.s.trations and display letters of the original have been reproduced and the type as closely approximates to the original as the printers have been able to find in a modern font.

There are no footnotes in the original text, and Mr. Hoover is responsible for them all. He has attempted in them to give not only such comment as would tend to clarify the text, but also such information as we have been able to discover with regard to the previous history of the subjects mentioned. We have confined the historical notes to the time prior to Agricola, because to have carried them down to date in the briefest manner would have demanded very much more s.p.a.ce than could be allowed. In the examination of such technical and historical material one is appalled at the flood of mis-information with regard to ancient arts and sciences which has been let loose upon the world by the hands of non-technical translators and commentators. At an early stage we considered that we must justify any divergence of view from such authorities, but to limit the already alarming volume of this work, we later felt compelled to eliminate most of such discussion. When the half-dozen most important of the ancient works bearing upon science have been translated by those of some scientific experience, such questions will, no doubt, be properly settled.

We need make no apologies for _De Re Metallica_. During 180 years it was not superseded as the text-book and guide to miners and metallurgists, for until Schluter's great work on metallurgy in 1738 it had no equal.

That it pa.s.sed through some ten editions in three languages at a period when the printing of such a volume was no ordinary undertaking, is in itself sufficient evidence of the importance in which it was held, and is a record that no other volume upon the same subjects has equalled since. A large proportion of the technical data given by Agricola was either entirely new, or had not been given previously with sufficient detail and explanation to have enabled a worker in these arts himself to perform the operations without further guidance. Practically the whole of it must have been given from personal experience and observation, for the scant library at his service can be appreciated from his own Preface. Considering the part which the metallic arts have played in human history, the paucity of their literature down to Agricola's time is amazing. No doubt the arts were jealously guarded by their pract.i.tioners as a sort of stock-in-trade, and it is also probable that those who had knowledge were not usually of a literary turn of mind; and, on the other hand, the small army of writers prior to his time were not much interested in the description of industrial pursuits.

Moreover, in those thousands of years prior to printing, the tedious and expensive transcription of ma.n.u.scripts by hand was mostly applied to matters of more general interest, and therefore many writings may have been lost in consequence. In fact, such was the fate of the works of Theophrastus and Strato on these subjects.

We have prepared a short sketch of Agricola's life and times, not only to give some indication of his learning and character, but also of his considerable position in the community in which he lived. As no appreciation of Agricola's stature among the founders of science can be gained without consideration of the advance which his works display over those of his predecessors, we therefore devote some attention to the state of knowledge of these subjects at the time by giving in the Appendix a short review of the literature then extant and a summary of Agricola's other writings. To serve the bibliophile we present such data as we have been able to collect it with regard to the various editions of his works. The full t.i.tles of the works quoted in the footnotes under simply authors' names will be found in this Appendix.

We feel that it is scarcely doing Agricola justice to publish _De Re Metallica_ only. While it is of the most general interest of all of his works, yet, from the point of view of pure science, _De Natura Fossilium_ and _De Ortu et Causis_ are works which deserve an equally important place. It is unfortunate that Agricola's own countrymen have not given to the world competent translations into German, as his work has too often been judged by the German translations, the infidelity of which appears in nearly every paragraph.

We do not present _De Re Metallica_ as a work of "practical" value. The methods and processes have long since been superseded; yet surely such a milestone on the road of development of one of the two most basic of human industrial activities is more worthy of preservation than the thousands of volumes devoted to records of human destruction. To those interested in the history of their own profession we need make no apologies, except for the long delay in publication. For this we put forward the necessity of active endeavour in many directions; as this book could be but a labour of love, it has had to find the moments for its execution in night hours, weekends, and holidays, in all extending over a period of about five years. If the work serves to strengthen the traditions of one of the most important and least recognized of the world's professions we shall be amply repaid.

It is our pleasure to acknowledge our obligations to Professor H. R.

Fairclough, of Stanford University, for perusal of and suggestions upon the first chapter; and to those whom we have engaged from time to time for one service or another, chiefly bibliographical work and collateral translation. We are also sensibly obligated to the printers, Messrs.

Frost & Sons, for their patience and interest, and for their willingness to bend some of the canons of modern printing, to meet the demands of the 16th Century.

_July 1, 1912._

The Red House, Hornton Street, London.

INTRODUCTION.

BIOGRAPHY.[1]

Georgius Agricola was born at Glauchau, in Saxony, on March 24th, 1494, and therefore entered the world when it was still upon the threshold of the Renaissance; Gutenberg's first book had been printed but forty years before; the Humanists had but begun that stimulating criticism which awoke the Reformation; Erasmus, of Rotterdam, who was subsequently to become Agricola's friend and patron, was just completing his student days. The Reformation itself was yet to come, but it was not long delayed, for Luther was born the year before Agricola, and through him Agricola's homeland became the cradle of the great movement; nor did Agricola escape being drawn into the conflict. Italy, already awake with the new cla.s.sical revival, was still a busy workshop of antiquarian research, translation, study, and publication, and through her the Greek and Latin Cla.s.sics were only now available for wide distribution.

Students from the rest of Europe, among them at a later time Agricola himself, flocked to the Italian Universities, and on their return infected their native cities with the newly-awakened learning. At Agricola's birth Columbus had just returned from his great discovery, and it was only three years later that Vasco Da Gama rounded Cape Good Hope. Thus these two foremost explorers had only initiated that greatest period of geographical expansion in the world's history. A few dates will recall how far this exploration extended during Agricola's lifetime. Balboa first saw the Pacific in 1513; Cortes entered the City of Mexico in 1520; Magellan entered the Pacific in the same year; Pizarro penetrated into Peru in 1528; De Soto landed in Florida in 1539, and Potosi was discovered in 1546. Omitting the sporadic settlement on the St. Lawrence by Cartier in 1541, the settlement of North America did not begin for a quarter of a century after Agricola's death. Thus the revival of learning, with its train of Humanism, the Reformation, its stimulation of exploration and the re-awakening of the arts and sciences, was still in its infancy with Agricola.

We know practically nothing of Agricola's antecedents or his youth. His real name was Georg Bauer ("peasant"), and it was probably Latinized by his teachers, as was the custom of the time. His own brother, in receipts preserved in the archives of the Zwickau Town Council, calls himself "Bauer," and in them refers to his brother "Agricola." He entered the University of Leipsic at the age of twenty, and after about three and one-half years' attendance there gained the degree of _Baccalaureus Artium_. In 1518 he became Vice-Princ.i.p.al of the Munic.i.p.al School at Zwickau, where he taught Greek and Latin. In 1520 he became Princ.i.p.al, and among his a.s.sistants was Johannes Forster, better known as Luther's collaborator in the translation of the Bible. During this time our author prepared and published a small Latin Grammar[2]. In 1522 he removed to Leipsic to become a lecturer in the University under his friend, Petrus Mosella.n.u.s, at whose death in 1524 he went to Italy for the further study of Philosophy, Medicine, and the Natural Sciences.

Here he remained for nearly three years, from 1524 to 1526. He visited the Universities of Bologna, Venice, and probably Padua, and at these inst.i.tutions received his first inspiration to work in the sciences, for in a letter[3] from Leonardus Casibrotius to Erasmus we learn that he was engaged upon a revision of Galen. It was about this time that he made the acquaintance of Erasmus, who had settled at Basel as Editor for Froben's press.

In 1526 Agricola returned to Zwickau, and in 1527 he was chosen town physician at Joachimsthal. This little city in Bohemia is located on the eastern slope of the Erzgebirge, in the midst of the then most prolific metal-mining district of Central Europe. Thence to Freiberg is but fifty miles, and the same radius from that city would include most of the mining towns so frequently mentioned in _De Re Metallica_--Schneeberg, Geyer, Annaberg and Altenberg--and not far away were Marienberg, Gottesgab, and Platten. Joachimsthal was a booming mining camp, founded but eleven years before Agricola's arrival, and already having several thousand inhabitants. According to Agricola's own statement[4], he spent all the time not required for his medical duties in visiting the mines and smelters, in reading up in the Greek and Latin authors all references to mining, and in a.s.sociation with the most learned among the mining folk. Among these was one Lorenz Berman, whom Agricola afterward set up as the "learned miner" in his dialogue _Bermannus_. This book was first published by Froben at Basel in 1530, and was a sort of catechism on mineralogy, mining terms, and mining lore. The book was apparently first submitted to the great Erasmus, and the publication arranged by him, a warm letter of approval by him appearing at the beginning of the book[5]. In 1533 he published _De Mensuris et Ponderibus_, through Froben, this being a discussion of Roman and Greek weights and measures.

At about this time he began _De Re Metallica_--not to be published for twenty-five years.

Agricola did not confine his interest entirely to medicine and mining, for during this period he composed a pamphlet upon the Turks, urging their extermination by the European powers. This work was no doubt inspired by the Turkish siege of Vienna in 1529. It appeared first in German in 1531, and in Latin--in which it was originally written--in 1538, and pa.s.sed through many subsequent editions.

At this time, too, he became interested in the G.o.d's Gift mine at Abertham, which was discovered in 1530. Writing in 1545, he says[6]: "We, as a shareholder, through the goodness of G.o.d, have enjoyed the proceeds of this G.o.d's Gift since the very time when the mine began first to bestow such riches."

Agricola seems to have resigned his position at Joachimsthal in about 1530, and to have devoted the next two or three years to travel and study among the mines. About 1533 he became city physician of Chemnitz, in Saxony, and here he resided until his death in 1555. There is but little record of his activities during the first eight or nine years of his residence in this city. He must have been engaged upon the study of his subjects and the preparation of his books, for they came on with great rapidity soon after. He was frequently consulted on matters of mining engineering, as, for instance, we learn, from a letter written by a certain Johannes Hordeborch[7], that Duke Henry of Brunswick applied to him with regard to the method for working mines in the Upper Harz.

In 1543 he married Anna, widow of Matthias Meyner, a petty t.i.the official; there is some reason to believe from a letter published by Schmid,[8] that Anna was his second wife, and that he was married the first time at Joachimsthal. He seems to have had several children, for he commends his young children to the care of the Town Council during his absence at the war in 1547. In addition to these, we know that a son, Theodor, was born in 1550; a daughter, Anna, in 1552; another daughter, Irene, was buried at Chemnitz in 1555; and in 1580 his widow and three children--Anna, Valerius, and Lucretia--were still living.

In 1544 began the publication of the series of books to which Agricola owes his position. The first volume comprised five works and was finally issued in 1546; it was subsequently considerably revised, and re-issued in 1558. These works were: _De Ortu et Causis Subterraneorum_, in five "books," the first work on physical geology; _De Natura Eorum quae Effluunt ex Terra_, in four "books," on subterranean waters and gases; _De Natura Fossilium_, in ten "books," the first systematic mineralogy; _De Veteribus et Novis Metallis_, in two "books," devoted largely to the history of metals and topographical mineralogy; a new edition of _Bermannus_ was included; and finally _Rerum Metallicarum Interpretatio_, a glossary of Latin and German mineralogical and metallurgical terms. Another work, _De Animantibus Subterraneis_, usually published with _De Re Metallica_, is dated 1548 in the preface.

It is devoted to animals which live underground, at least part of the time, but is not a very effective basis of either geologic or zoologic cla.s.sification. Despite many public activities, Agricola apparently completed _De Re Metallica_ in 1550, but did not send it to the press until 1553; nor did it appear until a year after his death in 1555. But we give further details on the preparation of this work on p. xv. During this period he found time to prepare a small medical work, _De Peste_, and certain historical studies, details of which appear in the Appendix.

There are other works by Agricola referred to by sixteenth century writers, but so far we have not been able to find them although they may exist. Such data as we have, is given in the appendix.

As a young man, Agricola seems to have had some tendencies toward liberalism in religious matters, for while at Zwickau he composed some anti-Popish Epigrams; but after his return to Leipsic he apparently never wavered, and steadily refused to accept the Lutheran Reformation.

To many even liberal scholars of the day, Luther's doctrines appeared wild and demagogic. Luther was not a scholarly man; his addresses were to the ma.s.ses; his Latin was execrable. Nor did the bitter dissensions over hair-splitting theology in the Lutheran Church after Luther's death tend to increase respect for the movement among the learned. Agricola was a scholar of wide attainments, a deep-thinking, religious man, and he remained to the end a staunch Catholic, despite the general change of sentiment among his countrymen. His leanings were toward such men as his friend the humanist, Erasmus. That he had the courage of his convictions is shown in the dedication of _De Natura Eorum_, where he addresses to his friend, Duke Maurice, the pious advice that the dissensions of the Germans should be composed, and that the Duke should return to the bosom of the Church those who had been torn from her, and adds: "Yet I do not wish to become confused by these turbulent waters, and be led to offend anyone. It is more advisable to check my utterances." As he became older he may have become less tolerant in religious matters, for he did not seem to show as much patience in the discussion of ecclesiastical topics as he must have possessed earlier, yet he maintained to the end the respect and friendship of such great Protestants as Melanchthon, Camerarius, Fabricius, and many others.

In 1546, when he was at the age of 52, began Agricola's activity in public life, for in that year he was elected a Burgher of Chemnitz; and in the same year Duke Maurice appointed him Burgomaster--an office which he held for four terms. Before one can gain an insight into his political services, and incidentally into the character of the man, it is necessary to understand the politics of the time and his part therein, and to bear in mind always that he was a staunch Catholic under a Protestant Sovereign in a State seething with militant Protestantism.

Saxony had been divided in 1485 between the Princes Ernest and Albert, the former taking the Electoral dignity and the major portion of the Princ.i.p.ality. Albert the Brave, the younger brother and Duke of Saxony, obtained the subordinate portion, embracing Meissen, but subject to the Elector. The Elector Ernest was succeeded in 1486 by Frederick the Wise, and under his support Luther made Saxony the cradle of the Reformation.

This Elector was succeeded in 1525 by his brother John, who was in turn succeeded by his son John Frederick in 1532. Of more immediate interest to this subject is the Albertian line of Saxon Dukes who ruled Meissen, for in that Princ.i.p.ality Agricola was born and lived, and his political fortunes were a.s.sociated with this branch of the Saxon House. Albert was succeeded in 1505 by his son George, "The Bearded," and he in turn by his brother Henry, the last of the Catholics, in 1539, who ruled until 1541. Henry was succeeded in 1541 by his Protestant son Maurice, who was the Patron of Agricola.

At about this time Saxony was drawn into the storms which rose from the long-standing rivalry between Francis I., King of France, and Charles V.

of Spain. These two potentates came to the throne in the same year (1515), and both were candidates for Emperor of that loose Confederation known as the Holy Roman Empire. Charles was elected, and intermittent wars between these two Princes arose--first in one part of Europe, and then in another. Francis finally formed an alliance with the Schmalkalden League of German Protestant Princes, and with the Sultan of Turkey, against Charles. In 1546 Maurice of Meissen, although a Protestant, saw his best interest in a secret league with Charles against the other Protestant Princes, and proceeded (the Schmalkalden War) to invade the domains of his superior and cousin, the Elector Frederick. The Emperor Charles proved successful in this war, and Maurice was rewarded, at the Capitulation of Wittenberg in 1547, by being made Elector of Saxony in the place of his cousin. Later on, the Elector Maurice found the a.s.sociation with Catholic Charles unpalatable, and joined in leading the other Protestant princes in war upon him, and on the defeat of the Catholic party and the peace of Pa.s.sau, Maurice became acknowledged as the champion of German national and religious freedom. He was succeeded by his brother Augustus in 1553.

Agricola was much favoured by the Saxon Electors, Maurice and Augustus.

He dedicates most of his works to them, and shows much grat.i.tude for many favours conferred upon him. Duke Maurice presented to him a house and plot in Chemnitz, and in a letter dated June 14th, 1543[9] in connection therewith, says: "... that he may enjoy his life-long a freehold house unburdened by all burgher rights and other munic.i.p.al service, to be used by him and inhabited as a free dwelling, and that he may also, for the necessities of his household and of his wife and servants, brew his own beer free, and that he may likewise purvey for himself and his household foreign beer and also wine for use, and yet he shall not sell any such beer.... We have taken the said Doctor under our especial protection and care for our life-long, and he shall not be summoned before any Court of Justice, but only before us and our Councillor...."

Agricola was made Burgomaster of Chemnitz in 1546. A letter[10] from Fabricius to Meurer, dated May 19th, 1546, says that Agricola had been made Burgomaster by the command of the Prince. This would be Maurice, and it is all the more a tribute to the high respect with which Agricola was held, for, as said before, he was a consistent Catholic, and Maurice a Protestant Prince. In this same year the Schmalkalden War broke out, and Agricola was called to personal attendance upon the Duke Maurice in a diplomatic and advisory capacity. In 1546 also he was a member of the Diet of Freiberg, and was summoned to Council in Dresden. The next year he continued, by the Duke's command, Burgomaster at Chemnitz, although he seems to have been away upon Ducal matters most of the time. The Duke addresses[11] the Chemnitz Council in March, 1547: "We hereby make known to you that we are in urgent need of your Burgomaster, Dr. Georgius Agricola, with us. It is, therefore, our will that you should yield him up and forward him that he should with the utmost haste set forth to us here near Freiberg." He was sent on various missions from the Duke to the Emperor Charles, to King Ferdinand of Austria, and to other Princes in matters connected with the war--the fact that he was a Catholic probably entering into his appointment to such missions. Chemnitz was occupied by the troops of first one side, then the other, despite the great efforts of Agricola to have his own town specially defended. In April, 1547, the war came to an end in the Battle of Muhlberg, but Agricola was apparently not relieved of his Burgomastership until the succeeding year, for he wrote his friend Wolfgang Meurer, in April, 1548,[12] that he "was now relieved." His public duties did not end, however, for he attended the Diet of Leipzig in 1547 and in 1549, and was at the Diet at Torgau in 1550. In 1551 he was again installed as Burgomaster; and in 1553, for the fourth time, he became head of the Munic.i.p.ality, and during this year had again to attend the Diets at Leipzig and Dresden, representing his city. He apparently now had a short relief from public duties, for it is not until 1555, shortly before his death, that we find him again attending a Diet at Torgau.

Agricola died on November 21st, 1555. A letter[13] from his life-long friend, Fabricius, to Melanchthon, announcing this event, states: "We lost, on November 21st, that distinguished ornament of our Fatherland, Georgius Agricola, a man of eminent intellect, of culture and of judgment. He attained the age of 62. He who since the days of childhood had enjoyed robust health was carried off by a four-days' fever. He had previously suffered from no disease except inflammation of the eyes, which he brought upon himself by untiring study and insatiable reading.... I know that you loved the soul of this man, although in many of his opinions, more especially in religious and spiritual welfare, he differed in many points from our own. For he despised our Churches, and would not be with us in the Communion of the Blood of Christ. Therefore, after his death, at the command of the Prince, which was given to the Church inspectors and carried out by Tettelbach as a loyal servant, burial was refused him, and not until the fourth day was he borne away to Zeitz and interred in the Cathedral.... I have always admired the genius of this man, so distinguished in our sciences and in the whole realm of Philosophy--yet I wonder at his religious views, which were compatible with reason, it is true, and were dazzling, but were by no means compatible with truth.... He would not tolerate with patience that anyone should discuss ecclesiastical matters with him." This action of the authorities in denying burial to one of their most honoured citizens, who had been ever a.s.siduous in furthering the welfare of the community, seems strangely out of joint. Further, the Elector Augustus, although a Protestant Prince, was Agricola's warm friend, as evidenced by his letter of but a few months before (see p. xv). However, Catholics were then few in number at Chemnitz, and the feeling ran high at the time, so possibly the Prince was afraid of public disturbances.

Hofmann[14] explains this occurrence in the following words:--"The feelings of Chemnitz citizens, who were almost exclusively Protestant, must certainly be taken into account. They may have raised objections to the solemn interment of a Catholic in the Protestant Cathedral Church of St. Jacob, which had, perhaps, been demanded by his relatives, and to which, according to the custom of the time, he would have been ent.i.tled as Burgomaster. The refusal to sanction the interment aroused, more especially in the Catholic world, a painful sensation."

A bra.s.s memorial plate hung in the Cathedral at Zeitz had already disappeared in 1686, nor have the cities of his birth or residence ever shown any appreciation of this man, whose work more deserves their grat.i.tude than does that of the mult.i.tude of soldiers whose monuments decorate every village and city square. It is true that in 1822 a marble tablet was placed behind the altar in the Church of St. Jacob in Chemnitz, but even this was removed to the Historical Museum later on.

He left a modest estate, which was the subject of considerable litigation by his descendants, due to the mismanagement of the guardian.

Hofmann has succeeded in tracing the descendants for two generations, down to 1609, but the line is finally lost among the mult.i.tude of other Agricolas.

To deduce Georgius Agricola's character we need not search beyond the discovery of his steadfast adherence to the religion of his fathers amid the bitter storm of Protestantism around him, and need but to remember at the same time that for twenty-five years he was entrusted with elective positions of an increasingly important character in this same community. No man could have thus held the respect of his countrymen unless he were devoid of bigotry and possessed of the highest sense of integrity, justice, humanity, and patriotism.

AGRICOLA'S INTELLECTUAL ATTAINMENTS AND POSITION IN SCIENCE.

Agricola's education was the most thorough that his times afforded in the cla.s.sics, philosophy, medicine, and sciences generally. Further, his writings disclose a most exhaustive knowledge not only of an extraordinary range of cla.s.sical literature, but also of obscure ma.n.u.scripts buried in the public libraries of Europe. That his general learning was held to be of a high order is amply evidenced from the correspondence of the other scholars of his time--Erasmus, Melanchthon, Meurer, Fabricius, and others.

Our more immediate concern, however, is with the advances which were due to him in the sciences of Geology, Mineralogy, and Mining Engineering.

No appreciation of these attainments can be conveyed to the reader unless he has some understanding of the dearth of knowledge in these sciences prior to Agricola's time. We have in Appendix B given a brief review of the literature extant at this period on these subjects.

Furthermore, no appreciation of Agricola's contribution to science can be gained without a study of _De Ortu et Causis_ and _De Natura Fossilium_, for while _De Re Metallica_ is of much more general interest, it contains but incidental reference to Geology and Mineralogy. Apart from the book of Genesis, the only attempts at fundamental explanation of natural phenomena were those of the Greek Philosophers and the Alchemists. Orthodox beliefs Agricola scarcely mentions; with the Alchemists he had no patience. There can be no doubt, however, that his views are greatly coloured by his deep cla.s.sical learning. He was in fine to a certain distance a follower of Aristotle, Theophrastus, Strato, and other leaders of the Peripatetic school. For that matter, except for the muddy current which the alchemists had introduced into this already troubled stream, the whole thought of the learned world still flowed from the Greeks. Had he not, however, radically departed from the teachings of the Peripatetic school, his work would have been no contribution to the development of science.

Certain of their teachings he repudiated with great vigour, and his laboured and detailed arguments in their refutation form the first battle in science over the results of observation _versus_ inductive speculation. To use his own words: "Those things which we see with our eyes and understand by means of our senses are more clearly to be demonstrated than if learned by means of reasoning."[15] The bigoted scholasticism of his times necessitated as much care and detail in refutation of such deep-rooted beliefs, as would be demanded to-day by an attempt at a refutation of the theory of evolution, and in consequence his works are often but dry reading to any but those interested in the development of fundamental scientific theory.

In giving an appreciation of Agricola's views here and throughout the footnotes, we do not wish to convey to the reader that he was in all things free from error and from the spirit of his times, or that his theories, constructed long before the atomic theory, are of the clear-cut order which that basic hypothesis has rendered possible to later scientific speculation in these branches. His statements are sometimes much confused, but we reiterate that their clarity is as crystal to mud in comparison with those of his predecessors--and of most of his successors for over two hundred years. As an indication of his grasp of some of the wider aspects of geological phenomena we reproduce, in Appendix A, a pa.s.sage from _De Ortu et Causis_, which we believe to be the first adequate declaration of the part played by erosion in mountain sculpture. But of all of Agricola's theoretical views those are of the greatest interest which relate to the origin of ore deposits, for in these matters he had the greatest opportunities of observation and the most experience. We have on page 108 reproduced and discussed his theory at considerable length, but we may repeat here, that in his propositions as to the circulation of ground waters, that ore channels are a subsequent creation to the contained rocks, and that they were filled by deposition from circulating solutions, he enunciated the foundations of our modern theory, and in so doing took a step in advance greater than that of any single subsequent authority. In his contention that ore channels were created by erosion of subterranean waters he was wrong, except for special cases, and it was not until two centuries later that a further step in advance was taken by the recognition by Van Oppel of the part played by fissuring in these phenomena. Nor was it until about the same time that the filling of ore channels in the main by deposition from solutions was generally accepted. While Werner, two hundred and fifty years after Agricola, is generally revered as the inspirer of the modern theory by those whose reading has taken them no farther back, we have no hesitation in a.s.serting that of the propositions of each author, Agricola's were very much more nearly in accord with modern views. Moreover, the main result of the new ideas brought forward by Werner was to stop the march of progress for half a century, instead of speeding it forward as did those of Agricola.

In mineralogy Agricola made the first attempt at systematic treatment of the subject. His system could not be otherwise than wrongly based, as he could scarcely see forward two or three centuries to the atomic theory and our vast fund of chemical knowledge. However, based as it is upon such properties as solubility and h.o.m.ogeneity, and upon external characteristics such as colour, hardness, &c., it makes a most creditable advance upon Theophrastus, Dioscorides, and Albertus Magnus--his only predecessors. He is the first to a.s.sert that bis.m.u.th and antimony are true primary metals; and to some sixty actual mineral species described previous to his time he added some twenty more, and laments that there are scores unnamed.