Elements known to the ancient world

Although the ancient conception of an element was quite different from the modem one, a few of the substances now recognized as chemical elements have been known and used since the dawn of history. Although no one knows who discovered these ancient building-stones of the universe, the writings of Pliny the Elder and Dioscorides and the Hebrew and Hindu Scriptures abound in interesting allusions to the metals, gold, silver, copper, iron, lead, tin, and mercury, and the non-metals, sulfur and carbon. 

During the centuries, man s conception of what constitutes a chemical element has undergone many other changes. Aristotle (384-322 B.C.) believed that the properties of substances are the result of the simultaneous presence or blending of certain fundamental properties (102). He 

Heraclitus, 540-475 B.C. Ascetic Greek philosopher and founder of metaphysics. He believed that fire is the primary substance, and that change is the only actuality in Nature. 

In the twelfth century there appeared in certain Latin works alleged to be translations from the Arabic the theory of the principles of metals namely mercury, which confers metallic properties, and sulfur, which causes the loss of these properties on roasting. Another principle, salt, which imparted refractoriness or fixity in the fire, was added later by the famous popularizer of medical chemistry, Paracelsus (85). 

In 1661 Robert Boyle published The Sceptical Chymist, a book in which he discussed the criteria by which one can decide whether a substance is or is not a chemical element. He concluded that the four Aristotelian elements and three principles commonly accepted in his time cannot be real chemical elements since they can neither compose nor be 

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