The whole work, which is of folio size, is illustrated by wood-cuts, which give a faithful idea of the nature of the several operations, and of the character of furnaces, trompes, bellows, and tools employed in them. It is by far the most important technical work of the sixteenth century, and it exercised great influence on the art of metallurgy. The descriptions—at least as regards European processes—are evidently the result of personal observation. Agricola visited the mines, and faithfully noted the different methods of sorting and washing the ores, the characters of which he accurately describes. His accounts of the various smelting operations are so detailed that it is obvious they must have been put together after personal inquiry. The study of metallurgy, indeed, was the main object of his life; and he devoted to its pursuit even the pension which had been settled on him by Maurice, Elector of Saxony. He became Mayor of Chemnitz, died there in 1555, and was buried at Zeitz. =Bernard Palissy= lived throughout the greater portion of the sixteenth century. Although not a professed chemist, nor a follower of any particular school, he was an ardent self-taught experimentalist and a keen and accurate observer, who greatly enriched ceramic art by his discoveries. =Johann Rudolf Glauber= was born at Karlstadt, in Bavaria, in 1604, and after a restless life died in Amsterdam in his sixty-fourth year. He published an encyclopædia of chemical processes, in which he describes the preparation of a great variety of substances of technical importance. The greater number of the pharmacopœias of the seventeenth century are indebted to him for their descriptions of the mode of manufacture of their official preparations. He discovered sodium sulphate—his _sal mirabile_, still frequently named after him—and introduced it into medicine.