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 Oxygen, O, Non Metal. Joseph Priestley was generally acknowledged as the discoverer of oxygen. By heating it via the sun rays focused on it by powerful lens. However Priestley first did not realize that he discovered a new substance. He supposed that he just separated one of the components. Priestley informed Antoine Laurent Lavoisier about his discovery. Is the most abundant element on the Earth; i.

Element Phosphorus, P, Non Metal. The name phosphorescence, used in physics for the after luminescence shown by certain substances after a previous exposure to light, is a relic of that usage. At the present day, the name phosphorus. The nerve and brain substances, more especially, are comparatively rich in phosphorus, which is there .

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.