The natural objects found on the surface of our earth, or within its crust at a moderate distance from the surface, may be conveniently Classified into three great groups or kingdoms — the animal, vegetable, and mineral kingdoms. The two first embrace every thing organic — that is to say, everything that is, or has been, endowed with life; these are largely made up Of the chemical element carbon combined with the elements (hydrogen and oxygen) of water. The mineral kingdom, on the other hand, includes all in organic bodies that have not been produced by the agency of life. Contrasted with materials of organic origin, they show a much greater diversity in the chemical elements that enter into their composition.