Many more instances might be cited, but enough has been said to show how much confusion has arisen through carelessness or unwarrantable assumption, and how desirable it is that it should be disentangled as far as possible. In this work the endeavor is made to give complete information, as outlined above, concerning all the names that have ever been introduced into the nomenclature of Mineralogy. Nearly all published works on this subject have been searched to prepare a complete list of such names, and all available sources of information have been consulted. Many facts have been received in private communications from correspondents at home and abroad, a list of whose names is appended. But a number of blanks still remain, after years of research, and the author greatly desires information on any of the points lacking.