Windswept_ The Story of Wind and Weather - Marq de Villiers [16]
The man who understood that things might be a little more complicated was Anaximander, a philosopher of the sixth century B.C. The sky and the earth and everything on it, he taught, were conjured into being when the great primordial sea was evaporated by celestial fires; everything left over is the consequence of basic oppositional forces—light and dark, dryness and wetness, heat and cold. He said nothing about air specifically, but his pupil Anaximenes took the discussion one significant step further. He suggested that air was itself an element, and the most important one at that: "Air is the first principle of things, for from this all things arise and into this all are resolved again." Its properties were intermediate between fire and water, and air was therefore the basic matter from which these two were formed. Some centuries later Plutarch, who was a great admirer of Anaximenes, quoted him as saying, "all things are [thus] generated by a certain condensation or rarefaction of it."4
The notion was obviously current in the schools of philosophy. Among the earliest surviving texts, dating from about the same period as Anaximander, is a theory contained in a document called the Derveni papyrus, discovered in 1962 half burned on top of a coffin; it had been part of the dead man's funeral pyre. Derveni's tale was an allegory about Orpheus, but in the text the author's worldview was clearly stated. The world had two unequal basic principles, fire and air, and air is, at the same time, divine and also called "mind." Cold air has the property of checking hot fire. Originally, fire was dispersed through the universe, created havoc, and prevented the formation of order, or kosmos. To set creation in motion, mind-air acted to concentrate fire in the stars and the sun: This made the world as we know it.
Anaximander
This was, even by ancient standards, pretty hit and miss, and there it rested until it was taken up by Aristotle (384-322 B.C.), the great synthesizer of Greek thought. The meteorological and chemical ideas codified by Aristotle remained "true" for more than 1,500 years. They can be summarized as two overweening concepts: the four elements of matter and the atomistic view of matter. These overlapped and reinforced each other, but were also to some degree in conflict—Aristotle himself agreed with the former but not the latter, and the debate he set off was the source of more than a thousand years of sometimes acrimonious philosophical and alchemical wrangling.
The first complete description of the four-elements theory dates back to a philosopher called Empedocles (490-430 B.C.), but his notes were restated more elaborately and concisely by Aristotle. All matter, in this view, was made up of four basic, irreducible elements: earth, air, fire, and water. In turn, these four basic pillars of the universe are derived from the four "properties," hotness and its opposite, coldness; and dryness and its opposite, wetness.
Fire and water are obvious opposites, according to Aristotle, and so are earth and air. They have nothing in common and share no properties. Each element existed somewhere in an ideal, or pure form, not found on Earth. Real or earthly things were impure mixtures of the ideal elements. Smoke, for example, was a mixture of the air and earth with some of the element of fire added. The elements could be changed into one another by removal of one property and addition of another—an idea later seized on by the medieval alchemists, the precursors of modern chemistry. Another point that seemed obvious was that the four elements had a natural tendency to separate in space; fire moved upward, away from the earth, and the