PROF. J. L. GUSTAV TSCHERMAK—Seysenegg, Hofrat, one of the most distinguished of modern mineralogists and petrologists, whose death was recently announced, was born at Littau, near Olmütz in Moravia, on April 19, 1836. He studied at the University of Vienna, and in 1857, while still a student, he accompanied Julius Schmidt in his examination of the extinct volcanoes of Moravia, and was responsible for much of the field work as well as for the subsequent determination and description of the specimens obtained. In 1858 he published his first paper, which dealt with the trachytes in the neighbourhood of Banov in Moravia. This was the earliest of a long succession of important publications spread over- more than sixty years. In 1861 he was received into the Faculty of Science of the University and acquired the right to give academical lectures. In 1862 he was appointed custodian to the Court collection of minerals.