George J. Brush entered on his scientific career at the moment when science and scientific methods of research were just beginning to be appreciated in this country, and he soon became one of the leading pioneers in the movement. While his half century of active service was largely occupied by administrative duties in connection with the Sheffield Scientific School, his interest in mineralogy never flagged. His papers on mineralogical subjects number about thirty, all of which were published in the Journal. These began in 1849, even before his graduation from college, and continued until his last paper (in collaboration with S. L. Penfield) appeared in 1883. Three of the early papers were written with J. Lawrence Smith as noted above. These papers first set in this country the standard for thorough and accurate scientific mineral investigation. Later in life he was active in the development of the remarkable mineral locality at Branchville, Conn., and, with the collaboration of E. S. Dana, published in the Journal (1878–90) five important articles on its minerals. This locality, with the exception of the zinc deposits at Franklin Furnace, N. J., was the most remarkable yet discovered in this country. Nearly forty different mineral species were found there, of which nine (mostly phosphates) were new to science. There has certainly been no other series of descriptive papers on a mineralogical locality of equal importance published in this country. In addition to publishing original papers, Brush did considerable editorial work in connection with the fourth (1854) and fifth (1868) editions of the System of Mineralogy and the Appendices to them. His Manual of Determinative Mineralogy, with a series of determinative tables adapted from similar ones by von Kobell, was first published in 1874. It was revised in 1878 and later rewritten by S. L. Penfield. This book did much to make possible the rapid and accurate determination of mineral species. Throughout his life, Brush was an enthusiastic collector of minerals, building up the notable collection that now bears his name. Perhaps, however, his most important contribution to the development of mineralogy in America lay rather in his influence upon his many students. With his enthusiasm for accurate and painstaking investigation he was an inspiration to all who came in contact with him and his own field and science in general owes much to that influence.