The little duchy of Nassau, so recently annexed to the kingdom of Prussia, has long been famous for its mineral wealth. It yields yearly about 350,000 tons of iron ore, principally Hematite, and about half that quantity of Manganese. Of its natural mineral water from Seltzers it exports above a million bottles annually. In its north-western corner are the Brown-Coal deposits of the Wester-wald; and to these sources of wealth must now be added more valuable and extensive deposits of phosphate of lime, which, though not long since discovered, have already attracted the attention of the leading agricultural chemists of this country. This discovery has its scientific attractions, as well as its commerical advantages; and, as I have lately had an opportunity of examining these deposits in detail, it may be of interest to the reader, if I record a few particulars concerning them.