that the summits of the Pyrenees are of a shelly and fetid marble; while the Andes are chiefly composed of clay, and pour out rivers of mud. When we compare these grand scenes with the little mountains or hills of Saxony, we must regret the perverseness of fate, which has confined Werner to such an insignificant field of observation. Nor can the travels of his disciples affect the question, for many have changed their sentiments upon their visits to Auvergne, and other volcanic countries; and observations of the great master alone merit confidence; for we all know, from Hogarth, how Richardson could read Greek through his son.

These introductory observations are not unnecessary in passing to new and grand divisions of the rocks, which have been blended and confounded under several vague denominations, but which are here separated into various great assemblages, for the sake of more clear detail, and more accurate knowledge. Under the important Mode of granite, rates.

Pretended

Substantial and Accidential

it has already been explained that felspar
and quartz, united with siderite or mica,
or with both, are indispensable attributes
of that substance. The mica may pass to
micarel, or even steatite; and the appear-
ance of schorl or garnets, not to mention
the
gems, cannot be considered as altering
the nature of the substance.

But the name granite has, on the contrary, by Gmelin and many other writers, been extended to almost every aggregation that can be conceived. Such heterogeneous aggregations are here arranged under the name of Composite Rocks; while some, as that beautiful rock called the Corsican granitel, are placed among the Anomalous, as departing from the usual rules observed by nature,

The latter six great divisions of the rocks, Divisions. being derived, not from the nature of the substances themselves, but from accidences or circumstances, may be called ACCIDENTIAL, or circumstantial; while the former divisions are SUBSTANTIAL. The chemical Mode therefore, so essential in

the substantial ranks, here becomes foreign to the object; and the terms Structure and Aspect, derived from the self-apparent nature of the stones themselves, would become yet more improper, as by far the greater part of these rocks are even compounded of various domains, united in one

mass.

necessary.

The term DOMAIN has been retained, New terms not in its former acceptation, which may strictly imply the preponderance or predominance of a particular earth or substance; but in a more general sense, equally applicable to all the twelve divisions; that is, merely a continuation of the metaphoric language of the Mineral Kingdom, Provinces, and Domains. In this sense it is indeed chiefly used in the first six divisions; the other implication, of predominance or preponderance, being of a secondary and subsidiary nature, and only a further recommendation of its propriety.

But the term Mode implying the chemical mode of combination, which is even

more essential than the nature and power of the substances combined, as appears from an infinite number of analyses, it cannot be admitted into these new divisions, derived from accidential, and not from substantial, differences, as has been just mentioned; and the inferior terms being equally objectionable, the adoption of a new appellation becomes indispensable. The word Nome. NOME has been adopted, as short and convenient, and as applied by the Greek writers to the districts of Egypt, the first country where chemistry and mineralogy appear to have been studied. It is therefore not only of classical authority, but has an affinity, so to speak, with the parent country of the science, and thus presents scientific recollections*. The author has the greatest aversion to unnecessary neology, the chief use of language being to be understood, and that the thoughts may be accurately perceived, as flowers or fruits

The word in all its relations seems strictly Greek, and is probably only a translation of a Coptic word, especially as Strabo informs us that the Nomes were divided into Toparchies.

in a vase of crystal: but when a science has assumed a new aspect, like chemistry, or is wholly new, like mineralogy, new words become indispensable to express new ideas.

For the sake of memory, and easy reference, the latter divisions follow the general succession of substances in the former: but this arrangement must not be understood to imply that any substance is predominant, as either may have greater or less importance in different parts of the same rock. After these considerations, the proper arrangement of the Composite Rocks will not be attended with much difficulty.

NOME 1. SIDERITE, WITH GARNET ROCK.

Siderite and garnet are substances of similar origin, alike influenced by iron; and their conjunction is naturally to be expected. Nodules of garnet rock may appear in a rock of siderite, or the reverse; but both are so equally balanced, that it would be improper to class them under either Mode.