Clock Works [antikvár]

II i s "'I;:; V' INTRODUCTION A HISTORY OF TIME Roman sun dial from Utica, Tunisia. Eauly man had UITI.H need for mechanical clocks; he would wake at sunrise and go to bed at sunset. With the growth of civilization, man, at least in highly developed societies, began to feel the need for a means of measuring time. hi approximately 3500 BC, the early Egyptians divided the day and night into 12 hours each; at this time, the length of the hours depended on the seasons of the year. It was not until 3000 bc that the Babylonians regularized the hours by making them all the same length of time. The Romans then devised a calendar which had 10 lunar months which began on 1 March. However as this still meant that the year fell short, a special month was then intercalated between February 23rd and 24th. In 46 BC Julius Caesar commissioned the Greek astronomer Sosigenes to devise a new calendar which was based on the solar year, with 365 days for three consecutive years and an extra day added to the shortest month every fourth year: the leap year as we now know it. In Summer at the mouth of the River Tigris, the Egyptians built great calendar clocks of large stone blocks, similar to the circular arrangement that remains at Stonehenge in Britain; il is thought that Stonehenge was used to tell the time and was probably also used as a form of observatory. Later, sundials closer to today's model were introduced. Later developments include a small, portable wooden shadow clock which consisted of a horizontal bar with a raised erosspiece at one end. The shadow would progress along the bar as the sun rose so the clock had to be positioned facing easi in the morning and west in the afternoon. The first clocks to calculate the full 24 An early 18th-century engraving of Stonehenge by Johannes Kip.