FORCHHAMMER, Johan Georg, a Danish mineralogist and geologist, was born at Husum on July 26, 1794, and died at Copenhagen on December 14, 1865. After studying at Kiel and Copenhagen from 1815 to 1818, he joined Oersted and Esmarch in their mineralogical exploration of Bornholm, and took a considerable share in the labours of the expedition. In 1820 he obtained his doctor’s degree by a chemical treatise De Mangano, and immediately after set out on a journey through England, Scotland, and the Faroe Islands. In 1823 he was named university lecturer on chemistry and mineralogy; in 1829 he obtained a similar post in the newly established polytechnic school; and in 1831 he was appointed professor of mineralogy in the university, and as such became curator of the geological museum. On the death of Oersted in 1851, he succeeded him as director of the polytechnic school and secretary of the academy of sciences. As a public instructor Forchhammer held a high place and contributed potently to the progress of his favourite studies in his native country. He delighted in the popularization of science, and frequently brought his knowledge and influence to bear on such practical questions as the introduction of gas into Copenhagen, the establishment of the fire-brigade at Rosenberg, or the boring of Artesian wells....