Monœcia and Diccia, the characters distinctive of the classes are employed for the orders. Polygamia has three orders, Monacia, Diaecia, Tricia; and the last class, Cryptogamia, is divided into four orders, consisting of the Filices or Ferns, the Musci or Mosses, the Algo, and the Fungi.

The genera are established upon characters derived from all the parts of fructification compared together, according to their number, figure, proportion, and situation; but as this volume was intended to contain all the plants known to the author, the natural characters thus formed could not be employed on account of their length, and he has used the essential character, which is shorter, and consists of those marks that serve to distinguish the genera from each other in the natural orders; while at the head of each class, the genera are synoptically disposed, being defined by their factitious characters, or those by which one is distinguished from another in the artificial order only.

The remarks which we have already made respecting the generic and specific names, apply equally to this department. These last, in the systems of former botanists, were lengthened descriptions, taken from various circumstances, and seldom in any degree distinctive; but Linnæus reduced them to twelve words at most, and derived them from some remarkable difference in the leaves, roots, stems, or other unvarying properties. These short phrases he continued to call the specific name, but they are now properly considered as the specific character; while he invented what he called the trivial name, consisting of a single word added to the generic, and which we now use as the specific.

The number of species mentioned in the Systema Naturæ amounts to upwards of 7800.

We come now to the third and last volume, containing his arrangement of the objects forming the mineral kingdom. This department has received less elucidation from him than the others. In 1736, he first digested a mineralogical system, in which he attempted to found the genera on definite characters; but he seems to have lost sight of the subject until obliged to attend to it when editing the twelfth edition of his work. There he prefixes to his arrangement a brief account of his theory on the origin of fossil bodies in general, and of their several combinations. His views, however, are extremely fanciful, and cannot be said to have produced any beneficial effect on the study of this science. As they have long ago passed into oblivion, it may afford amusement, if not instruction, to present an outline of them.

The earth originated from water, agreeably to the testimony of Moses, Thales, and Seneca! The sea becoming pregnant gradually produced the dry land, from which the dew rose by evaporation, was elevated into clouds, and again descended in showers. No certain indications of a universal deluge have yet been found, but we every where perceive that land has been formed from the sea.

The water of the ocean, being impregnated by the air, produces a twin birth; the saline principle, which is masculine, soluble, acrid, transparent, and crystalline; the earthy, which is feminine, fixed, viscid, opaque, and attractive. It also nourishes the animal and the vegetable beings, which in course of time are reduced to earth.

The salts, which are sapid, polyhedral, transparent, multiplicative, soluble into infinitely minute particles, although always retaining the same form, and again becoming concrete so as to form larger particles of the same figure, generate various minerals by crystallizing.

Nitrum, which is aerial, by covering over increases sand.

Muria, which is marine, by corroding attracts clay. Natrum, which is of animal origin, by deliquescing coagulates lime.

Alumen, which is of vegetable origin, by ramifying produces earthy soil.

These are the Fathers of minerals.

The Earths, which are powdery, drying, soluble, fixed, primitive, are generated or reproduced by crystallizing, precipitating, fermenting, or putrefying. From them, by crystallization or attraction, minerals are reformed, and these again are resolved into earths and regenerated.

Clay is the precipitation of the viscid water of the sea; and is opaque, plastic, friable, capable of hardening, and fireless.

Sand is the crystallization of turbid rain-water; and is transparent, juiceless, giving sparks, durable, and capable of being vitrified.

Mould is the decomposition of fermenting vegetables; and is black, bibulous, powdery, and combustible.

Lime is the decomposition of putrescent animal substances; and is whitish, absorbent, mealy, penetrable, and effervescent.

Clay, the earth of sea-water, is hardened into talc, when redissolved is regenerated in the form of as

bestus, and when more intimately dissolved resumes the form of mica. Sand, the earth of rain-water, when thrown on the land and dried, forms driftsand, which finally becomes gravel. Both substances, when under ground, are converted into sandstone, and when mixed with other matters form pebbles, which grow into stones. When redissolved and crystallized, it produces quartz. Mould, the earth of vegetables, is hardened into fissile slate, which being impregnated with bitumen becomes coal. It is dissolved into ochre, and regenerated into tophus. Lime, the wife of natron, produces marble, dissolved and saturated with acid is crystallized into gypsum. Both are decomposed by the elements into chalk, which, acted upon by rain-water, becomes flint; and when dissolved, is crystallized into spar (or calcedony).

Such are the Mothers of minerals.

It is unnecessary to follow our author, while he states the principles of his sexual system of minerals, through the forms and modifications of crystals, metals, rocks, and petrifactions. His scheme of geology may be described as follows:-The strata of the earth are generally parallel to each other, although not always so, nor always of marine origin. The lowest is of sandstone (cos), the second of slate, the third of marble filled with marine petrifactions, the fourth of slate, the uppermost of the saxose kind, which includes granite, porphyry, trap, conglomerate, and puddingstone. It is obvious that the ocean has produced the land. It is rendered turbid by nitrous showers, precipitates, and is crystallized into sand, which covers the bottom of the sea. The surface of it is here and there covered over to a great

extent with floating fuci, the mould derived from which gradually descends, while the lighter particles help to form a floating meadow. Marine vermes, the mollusca, testacea, lithophytes, and zoophytes, together with fishes and sea-birds, feed beneath this floating meadow. An argillaceous sediment falls down in the quiet water, and this, together with the calcareous shells of the marine vermes, gradually forms a heap, which rises to the surface, while the pressure agitating the water drives out the marine animals. On the rock thus formed, the sea casts up great quantities of fuci, which are converted into mould, until at length the sandy earth rises above the surface, dries, is driven about, and concresces into gravel and sandstone. In the course of ages, the sand is hardened into sandstone, the mould into bituminous shale and coal, the clay into marble, other layers of mould into other beds of shale or slate, and other masses of sand into gravel and conglomerate. This again is converted into pebbles, these into stones, the stones into rocks. At length, the water subsiding, the mass becomes a mountain. Had Linnæus been as unfortunate in his other theories as in this, his name would have been long ago forgotten.

However fanciful his theoretical views may be, his classification is not unworthy of praise, and his specific definitions are generally intelligible to a modern mineralogist; but this is nearly all, however, that can be said in their favour. He divides the mineral kingdom into three classes, under the names

of Petræ, Mineræ, and Fossilia.

These are again

subdivided into several orders, and the number of genera amounts to fifty-four.