IV PREFACE, principal parts of the Science of Mine ralogy, with the difcoveries and improve ments which have been made, of late years, on the Continent, and with fuch as I could add from my own induftry and knowledge; and I hope, I have fully illuflrated the importance and utility, which this Science fo juftly claims. To improve this Work in propor tion as my , knowledge may increafe, will be my future endeavour. In this, I intend to follow the plan, of which, I have given a fketch in the Appendix to this Volume, and of which, the Conti nuation {ball follow in the form of a Supplement. This Continuation I fhall publifh from time to time, in Numbers, according to the advancements and dis coveries which may be made in the Science;