Padua, and at these institutions 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 association 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 At about this time he began De Re Metallica—not to be published for twenty-five years.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 passed through many subsequent editions.

At this time, too, he became interested in the God's Gift mine at Abertham, which was discovered in 1530. Writing in 1545, he says[6]: "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."

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 tithe 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 classification. 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 masses; 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