A non-metallic element known only in the solid form and very widely distributed. It enters into the composition of all organic structures, whether animal or vegetable. It is found in all the animal tissues, and, with oxygen, hydrogen, nitrogen, and sulphur, makes up the whole plant-wood, leaves, and flowers. All vegetable products-such as sugar, starch, gum-arabic, alcohor, oils-consist largely of carbon combined with oxygen and hydrogen. Carbon is the chief constituent of coal; and coal, when heated so as to expel its gases, is turned into coke, which is also carbon. Carbon is also found under the form of what is often named blacklead, but which is properly called plumbago or graphite. This is the substance from which pencils are made. The diamond, though widely different in appearance from all the other forms, is pure carbon.