INTRODUCTION. x1X 
exercised in nutrition, developement, and reproduction. The principal 
part of the nourishment of plants, is derived from their roots; and 
their texture is composed of tissues and vessels formed for absorbing, 
retaining, and elaborating the nutritive juices, drawn from the soil 
and atmosphere. The vegetable kingdom, likewise, has this analogy 
among others, with the animal; that the function of reproduction is 
performed through the medium of sexual organs. These organs are 
protected by the cerolla, or flower; and all the display of color and 
form in this essential part of vegetables, is, like the notes of many 
birds, connected with the important purpose of the continuation of the 
species. The number, form, and situation of these organs, has afford- 
ed to Linneus the chief characters in his simple, though artificial 
arrangement of the classes and orders of plants, in consequence termed 
the sexual system; while what is called the natural system, proposed 
by Jussien, is founded chiefly upon the presence or absence, and the 
nature of the seed, or germ—the relative position of the stamina— 
and upon the absence or presence, and form, of the corolla. 
The Minerat Kinepom is distinguished from the other two great 
divisions, by the absence of vitality and organic structure. Forming 
the solid crust of the globe, the mineral kingdom, in its various com- 
pounds, affords support and sustenance to the organized beings existing 
on its surface. The constitution and arrangement of the mineral 
strata have given rise to various theories, to account for their present 
appearance ; but facts have not yet been sufficiently multiplied to 
afford a satisfactory solution. One great line, however, is drawn be- 
tween those mineral strata which have been termed primitive, in 
which no organized remains occur, and those of posterior formation, 
in which the remains of plants and animals are discovered. The 
principal external characters of the mineral kingdom are taken from 
their specific gravity, as compared with water,—hardness,—crystalli- 
zation, when it exists,—and cleavage, or the direction of the lamelle, 
which, in many minerals, is regulated by the relation of the external 
surfaces to the primary crystal, or form. Of a less constant kind are 
color, degree of transparency, fracture, and the streak which many 
minerals show, when scratched. The physical characters are fusibi- 
lity, solubility, phosphorescence, electricity, magnetism, and refraction. 
Linneus, in his Systema Nature, arranged the Animal kingdom 
into six classes, the Vegetable kingdon into twenty-four, and the 
Mineral kingdom into three. As this arrangement, though now 
modified and extended in many of its parts, as will be detailed elses 
