Columbus, the Cannon Ball and the Common Pump [antikvár]

1 Wedlock of East and West Two earlier volumes of the story of hov\^ science began embrace four periods of the history of civilisation. The first is associated in the western world with the perfection of the calendar by the priestly astronomers of Egypt and Iraq and with the beginnings of mathematics in the service of temple architecture, tribute and trade. Though astronomy and mathematics continued to progress in Iraq till after the conquests of Alexander, i.e. about 300 B.C., we may date our first period from 3500 to 1500 B.C. By 1500 B.C. maritime trade had begun between Egypt, Phoenicia (Lebanon), Crete and Cyprus. As it extended its range beyond the Mediterranean, a new class of literate master mariners collated their experience of the changing aspect of the heavenly bodies as their ships sailed into more northerly and southerly latitudes. By about 500 B.C. there emerged from such experience among the sea-faring Greeks the recognition that the earth is a spherical body. In the Greek-speaking colonies and mainland, geometry and geography had reached their highest level before 300 B.C. The scene now shifts back to Egypt and Iraq where the conquests of Alexander the Great had planted colonies of Greek veterans and scholars. This phase spanned some six centuries, roughly from 300 B.C. to A.D. 300, during which the great university founded by one of Alexander's generals in the city named after the conqueror was the centre of all learning in the west. Its main achievements were the determination of the earth's circumference and of the distance of the moon from the earth, the construction of star maps and earth maps in latitude and longitude, discovery of the geometrical laws of reflection from plane and curved mirrors, of the principle of the lever and that of buoyancy. It also brought mathematics into the service of astronomy by construction of trigonometrical tables—