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ATOM IN MODERN SCIENCE 17 substance as other rocks So, when they obtained
strong shining substances from these ores, they , explained the transformation by saying that the nietal was formed by a union of earth and fire The different qualities of different metals were accounted by saying that different proportions of earth and fire atoms went into their formation Thus, gold contained more fire than iron
Reasoning that if fire atoms were added to iron or copper it would turn into gold, the alchemists of Middle Ages spent much time to make synthetic gold from cheaper metals The fallacy of their theory and practice lay in their belief that metals were composite rather than elementary substances The transformation of iron ore into metallic iron in the blast furnace is not due to a union of atoms as ancients believed but quite the reverse Most metallic ores are oxides and the process of making metal is the separation of oxygen atoms from the molecules of the oxide, leaving the atoms of pure metal On the other hand the rust which appears on the surface of iron objects due to moisture is not earth substance left behind after the escape of fire atoms from the iron substance but the forniation of iron oxide resulting from the union of iron atoms and oxygen atoms from the water or air
Thus whereas, an ancient scienust would express the processing of iron ore by the formula (a) Earth atom + fire atom = Iron atom
and the rusting of iron by (b) Iron = Earth + Fire
(rust) (b) The modern chemist would express the same
by
(a) FeO:= Fe + O2 (b), Fe + 0:= FeO2
