Home › E › Earth (Originally in the opinion)

Earth (Originally in the opinion)

originally, in the opinion of of the four elements, of which all maof the four elements, of which all material things in the world were held to be composed, the others being fire, air, and water. Not even one of the four is really a simple substance.

Five Later, a name given to various substances, opaque, insipid to the taste, in- combustible, and, when dry, friable, i, e., easily separated into particles. divisions of them were recognized: (a) Boles, (b) Clays, (c) Marls, (d) Ochers, and (e) Tripolis. Under these catemetals, cerium, aluminium, beryllium, gories were ranked the oxides of the zirconium, yttrium, erbium, thorium, etc. metals These oxides are insoluble in water, and are all very rare except aluminum. They are difficult to separate from each other, occurring together in rare minerals, and hence the number of metals belonging to this class is not known.