THE ancient Greeks may well have had a word for everything, but they had strange ideas, by our reckoning, about the weather and the universe. Around 450 BC, for example, Pythagoras believed the sun had once "run out of its pathway", and that the Milky Way that appears across the centre of our night time sky was, as it were, the "scorch mark" left in its wake.
Theophrastus, 150 years later, disagreed: he declared that the Milky Way was the joining together, or "seam", of the two halves of the celestial globe.
Greek theories about the weather were based on the assumption that the world was composed of four basic elemeo's earth, water, air and fire. These elements were neatly arranged to form four concentric spheres with earth in the middle, surrounded by water, and both in turn lying within a vast envelope of air.
The fourth element, fire, occupied the outermost fringes of the world. This division between the elements was not rigid: earth, for example, obviously projected above the water here and there, and fire was often seen to descend to earth in the form of lightning.
But when Aristotle came along, he added some notions of his own. He declared that the universe could be divided into two regions, separated from each other by the orbit of the moon. Nearest the earth was the terrestrial region and it was in this that the four "known" elements were found. But outside the moon's orbit was the celestial zone, home of the planets, and this region he held to be filled with a fifth element, or quintessence, that he called ether.
Thunder and lightning occurred when some of this ether descended into the terrestrial zone. The ether sizzled in the atmosphere with a fiery glow which was the lightning; but since the clouds contained moisture, this fire was instantly extinguished, causing the loud spluttering noise that was the thunder.
But the ancient Greeks were on firmer ground when it came to climate. They were familiar with the hot arid lands of North Africa, the warm and relatively moist countries of southern Europe, and the colder northern regions, so it was natural for them, when thinking about these matters, to place the emphasis on latitude and on the inclination of the rays of the noonday sun.
They divided the known world into climatic zones which were horizontal strips on the map. Each was classified with references to the angle of the sun at that latitude, and hence we have the word "climate", which comes from the Greek word kilma, meaning "slope" or incline".