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PREFACE.

T

HE practical part of the following work was gradually collected when the writer was very young; and what was begun to be written in detached fheets, afterwards became the materials of an interesting treatise. This part, indeed, may justly be deemed the most valuable of the whole, as it tends to inform the publick of matters very little understood or confidered beyond the confines of a Mineral district.

Minerals that are plenty and precious being generally confined to small tracts of country and a barren foil, are therefore remote from that publick obfervation which commerce and agriculture fo deservedly attract: yet it is a matter of astonishment, that an object of the first national consequence, in point of time, fhould fo long remain, even to the present hour, a fecret limited to a few illiterate people. It is well known, that Tin and Lead were the firft and grandeft ftaples of Great-Britain, particularly the former, which introduced a trade and navigation before unknown to the discoverers of our weftern coafts. This trade founded on Mining ftill fubfifts, with many practical improvements and difcoveries; and though corn and wool have contributed the largest share of riches and population to these flourishing kingdoms, yet that confideration does not by any means lessen the importance of the Mining interest. When we reflect upon the vast profufion of Silver, Tin, Copper, Lead, Iron, and Coal, yearly produced from the bowels of our Mines, which exceedingly furpaffes our internal consumption, and therefore muft afford a very confiderable branch of commerce; we shall find it difficult to account for that fupineness, which has hitherto declined the investigation of a subject of so much national importance.

The want of fuch affiftance, in the direction of the useful art of Mining, as it is hoped this treatise may afford, has been long complained of. It cannot, however, be denied that

our Mines are mostly well conducted; yet no fmall advantages may be derived from reducing the vague practice of common Miners to a regular science, and bringing the experience of many into a fingle point of view. Nor will those advantages be confined folely to practical Miners: every corner of this island, Ireland, and many of the colonies, abounds with a variety of Minerals, wholly unknown to the poffeffors; and was the knowledge of the indications of Metals, and the mode of working Mines more diffused, new difcoveries would daily be made to the great profit of landed proprietors, and the advantage of the publick, by increafing its revenue, and employing confiderable numbers of the laborious poor. As a ftriking proof of the want of fuch a treatise, before the latter end of the last century, vast quantities of rich Copper Ore in Cornwall were thrown away as ufelefs! Indeed, it may be fafely faid, that eleventwelfths of his Majefty's fubjects are totally unacquainted with any part or branch of our enquiry, that by itself, and its great confumption of various materials, brings in fo great a revenue to the crown, and so much wealth to the community.

To acquire a competent knowledge in Mines, &c. a long refidence in their vicinity is certainly neceffary; and this advantage, at least, I can with truth lay claim to: yet as this is the writer's first attempt in literary compofition, it will, for that reafon, have many faults; and he must rely on the candour of the publick for the favourable reception of an undertaking that ought long ago to have employed the ableft hand. However, I have not omitted to take the opinions of many perfons well verfed in the various departments of this work, which, from the number of natural and practical difcoveries it contains, and the vaft importance of the general fubject, I may venture to pronounce, with all its faults, a valuable acquifition to the library of every nobleman and gentleman in these 'kingdoms.

The great parts of this work are arranged in the following order. The firft book treats of the origin, formation, and fubftance of Minerals and Metals; the firft and fecond chapters of which inculcate the doctrine of water, as the folvent, vehicle, and cement of Metals and Minerals, or their principles, in proportion to the faturation of the one, and the magnetism of the refpective nidufes of the other. The theory here given, is, in some instances, established in the procefs of precipitation. The third chapter, which treats of the fubftances of Minerals, Metals,

and