Element Beryllium, Be, Alkaline Earth Metal. Occupies the same position among the alkaline earth metals as lithium does among the alkali metals. Its combining weight is the smallest, and its similarity to the other elements of the group is least. Its properties exhibit a distinct tendency towards the next group, that of the earth metals. The combining weight of beryllium amounts to 9. Besides the typical divalent ion Be. Beryllion forms various salts, of which the chloride, Be. And the sulphate, Be.

Element Carbon, C, Non Metal. Sugar charcoal is much purer than wood charcoal, because in it the presence can easily be avoided of non-volatile impurities which are present in the case of wood charcoal, and which, on complete combustion, remain behind as a grey powder, the ash. The properties of this form of carbon are the well-known black colour, a small density, easy combustibility, small conductivity for heat and electricity, and a low degree of hardness. From ancient times are amorphous carbon.

Element Magnesium, Be, Alkaline Earth Metal. Magnesium bears the same relation to calcium as sodium does to potassium. This relation finds expression not only in the values of the combining weights, but also in the similarities to the other members of the group. This is particularly well seen in the fact that magnesium. Is now manufactured in very large amount by electrolysis, and is used for various purposes. It is a white, rather tough metal, which keeps fairly well in the air; it is scarcely attac.

Element Silicon, Si, Metalloid. Silicon stands to carbon in the same relation as sulphur to oxygen. The two elements are similar in many respects, but differ more from one another than, for example, chlorine, bromine, and iodine do. Like carbon, occurs in several forms, of which an amorphous and a crystalline form are accurately known. Amorphous silicon is obtained by conducting its chlorine or fluorine compound over heated potassium; the metal unites with the halogen, and the silicon.

Element Aluminium, Al, Poor Metal. Of all the light metals, aluminium. It forms a constituent of almost all crystalline silicate rocks; and of the secondary formations, the clays and slate formations are formed from aluminium silicate. A knowledge of the compounds of this metal, therefore, extends back as far as chemical knowledge at all can be traced. While, even at comparatively high temperatures, massive aluminium is only superficially and inappre.