CHAPTER VI.

OF AGRICOLA AND METALLURGY.

I have been induced by a wish to prosecute the history of the opinions first supported by Paracelsus, and carried so much further by Van Helmont and Sylvius, to give a connected view of their effects upon medical practice and medical theory; and I have come to the commencement of the eighteenth century, without taking notice of one of the most extraordinary men, and one of the greatest promoters of chemistry that ever existed: I mean George Agricola. I shall consecrate the whole of this chapter to his labours, and those of his immediate successors.

George Agricola was born at Glaucha, in Misnia, in the year 1494. When a young man he acquired such a passion for mining and minerals, by frequenting the mountains of Bohemia, that he could not be persuaded to relinquish the study. He settled, indeed, as a physician, at Joachimstal; but his favourite study engrossed so much of his attention, that he succeeded but ill in his medical capacity. This induced him to withdraw to Chemnitz, where he devoted himself to his favourite pursuits. He studied the mineralogical writings of the ancients with the most minute accuracy; but not satisfied with this, he visited the mines in person, examined the processes followed by the miners in extracting the different ores, and in washing and sorting them. He made collections of all the different ores, and studied their nature and properties attentively: he likewise collected information about the methods of smelting them, and extracting from them the metals in a state of purity. The information which he collected, respecting the mines wrought in the different countries of Europe, is quite wonderful, if we consider the period in which he lived, the little intercourse which existed between nations, and the total want of all those newspapers and journals which now carry every new scientific fact with such rapidity to every part of the world.

Agricola died at Chemnitz in the year 1555, after he had reached the sixty-first year of his age. Maurice, the celebrated Elector of Saxony, settled on him a pension, the whole of which he devoted to his metallurgic pursuits. To him we find him dedicating the edition of his works which he published in the year of his death, and which is dated the fourteenth before the calends of April, 1555. He even spent a considerable proportion of his own estate in following out his favourite investigations. In the earlier part of his life he had expressed himself rather favourable to the protestant opinions; but in his latter days he had attacked the reformed religion. This rendered him so odious to the Lutherans, at that time predominant in Chemnitz, that they suffered his body to remain unburied for five days together; so that it was necessary to remove it from Chemnitz to Zeitz, where it was interred in the principal church.

His great work is his treatise De Re Metallica, in twelve books. In this work he gives an account of the instruments and machines, and every thing connected with mining and metallurgy; and even gives figures of all the different pieces of apparatus employed in his time. He has also exhibited the Latin and German names for all these different utensils. This work may be considered as a very complete treatise on metallurgy, as it existed in the sixteenth century. The first six books are occupied with an account of mining and smelting. In the seventh book he treats of _docimasy_, or the method of determining the quantity of metal which can be extracted from every particular ore. This he does so completely, that most of his processes are still followed by miners and smelters. He gives a minute and accurate account of the furnaces, muffles, crucibles, &c., almost such as are still employed, with minute directions for preparing the ores which are to be subjected to examination, the fluxes with which they must be mixed, and the precautions necessary in order to obtain a satisfactory result. In short, this book may be considered as a complete manual of docimasy. How much of the methods given originated with Agricola it is impossible to say. He probably did little more than collect the scattered processes employed by the smelters of metals, in different parts of the world, and reduce the whole to a regular system. But this was a great deal. Perhaps it is not saying too much, that the great progress made in the chemical investigation of the metals, was owing in a great measure to the labours of Agricola. Certainly the progress made by the moderns, in the difficult arts of mining and metallurgy, must in a great measure be ascribed to the labours of Agricola.

In the eighth book he describes the mechanical preparation of the ores, and the mode of roasting them, either in the open air or in furnaces. The ninth book is occupied with an account of smelting-furnaces. It contains also a description of the processes for obtaining mercury, antimony, and bismuth, from their ores. The tenth book treats of the separation of silver and gold from each other, by means of nitric acid and aqua regia: minute directions for the preparation of which are given. The modes of purifying the precious metals by means of sulphur, antimony, and cementations, are also described. In the eleventh book he treats of the method of purifying silver from copper and iron, by means of lead. He gives an account also of the processes employed for smelting and purifying copper. In the twelfth book he treats of the methods of preparing common salt, saltpetre, alum, and green vitriol, or sulphate of iron: of the preparation and purification of sulphur, and of the mode of manufacturing glass. In short, Agricola’s work De Re Metallica is beyond comparison the most valuable chemical work which the sixteenth century produced, and places the author very high indeed among the list of the improvers of chemistry.

The other works of Agricola are his treatise De Natura Fossilium, in ten books; De Ortu et Causis Subterraneorum, in five books; De Natura eorum quæ effluunt ex Terra, in four books; De veteribus et novis Metallis, in two books; and his Bermannus sive de re metallica Dialogus. The treatise De veteribus et novis Metallis is amusing. He not only collects together all the historical facts on record, respecting the first discoverers of the different metals and the first workers of mines, but he gives many amusing anecdotes nowhere else to be found, respecting the way in which some of the most celebrated German mines were discovered. In the second book he takes a geographical view of every part of the known world, and states the mines wrought and the metals found in each. We must not suppose that all his statements in this historical sketch are accurate: to admit it would be to allow him a greater share of information than could possibly belong to any one man. He frequently gives us the authority upon which his statements are founded; but he often makes statements without any authority whatever. Thus he says, that a mine of quicksilver had been recently discovered in Scotland: the fact however, is, that no quicksilver-mine ever existed in any part of Britain. There was, indeed, a foolish story circulated about thirty years ago, about a vein of quicksilver found under the town of Berwick-upon-Tweed; but it was an assertion unsupported by any authentic evidence.

Many years elapsed before much addition was made to the processes described by Agricola. In the year 1566, Pedro Fernandes de Velasco introduced a method of extracting gold and silver from their ores in Mexico and Peru by means of quicksilver. But I have never seen a description of his process. Alonzo Barba claims for himself, and seemingly with justice, the method of amalgamating the ores of gold and silver by boiling. Barba was a Spanish priest, who lived about the year 1609, at Tarabuco, a market-town in the province of Charcso, eight miles from Plata, in South America. In the year 1615 he was curate at Tiaguacano, in the Province of Pacayes, and in 1617, he lived at Lepas in Peru. He is said to have been a native of Lepe, a small township in Andalusia, and had for many years the living of the church of St. Bernard at Potosi. His work on the amalgamation of gold and silver ores appeared at Madrid in the year 1640, in quarto.[174] In the year 1629 a new edition of it appeared with an appendix, under the title of “Trattado de las Antiquas Minas de España de Alonzo Carillo Lasso.” The English minister at the Court of Madrid, the Earl of Sandwich, published the first part of it in an English translation at London, in 1674, under the title of “The First Book of the Art of Metals, in which is declared the manner of their generation, and the concomitants of them, written in Spanish by Albaro Alonzo Barba. By E. Earl of Sandwich.”

[174] It is entitled, “El Arte de los Metales, en que se ensena el verdadero beneficio de los de oro y plata por azoque,” &c.

The next improver of metallurgic processes was Lazarus Erckern, who was upper bar-master at Kuttenberg, in the year 1588, and was superintendent of the mines in Germany, Hungary, Transylvania, the Tyrol, &c., to three successive emperors. His work has been translated into English under the title of “Heta Minor; or the laws of art and nature in knowing, judging, assaying, fining, refining, and enlarging the bodies of confined metals. To which are added essays on metallic words, illustrated with sculptures. By Sir J. Pettus. London, 1683, folio.” But this translation is a very bad one. Erckern gives a plain account of all the processes employed in his time without a word of theory or reasoning. It is an excellent practical book; though it is obvious enough that the author was inferior in point of abilities to Agricola. His treatment of Don Juan de Corduba, who offered, in 1588, to put the Court of Vienna in possession of the Spanish method of extracting gold and silver from the ores by amalgamation, as related by Baron Born in his work on amalgamation, shows very clearly that Erckern was a very illiberal-minded man, and puffed up with an undue conceit of his own superior knowledge.[175] Had he condescended to assist the Spaniard, and to furnish him with proper materials to work upon, the Austrians might have been in possession of the process of amalgamation with all its advantages a couple of centuries before its actual introduction.

[175] Born’s New Process of Amalgamation, translated by Raspe, p. 11.

I need not take any notice of the docimastic treatises of Schindlers and Schlutter, which are of a much later date, and both of which have been translated into French, the former by Geoffroy, junior; the latter by Hellot. This last translation, in two large quartos, published in 1764, constitutes a very valuable book, and exhibits all the docimastic and metallurgic processes known at that period with much fidelity and minuteness. Very great improvements have taken place since that period, but I am not aware of any work published in any of the European languages, that is calculated to give us an exact idea of the present state of the various mining and metallurgic processes--important as they are to civilized society.

Gellert’s Metallurgic Chemistry, so far as it goes, is an excellent book.