| In this series of lectures about the history of weather forecasting, |
| I'll start by examining its early history - |
| that'll be the subject of today's talk. |
| Ok, so we'll start by going back thousands of years. |
| Most ancient cultures had weather gods, |
| and weather catastrophes, such as floods, |
| played an important role in many creation myths. |
| Generally, weather was attributed to the whims of the gods, |
| as the wide range of weather gods in various cultures shows. |
| For instance, there's the Egyptian sun god Ra, |
| and Thor, the Norse god of thunder and lightning. |
| Many ancient civilisations developed rites such as dances |
| in order to make the weather gods look kindly on them. |
| But the weather was of daily importance: |
| observing the skies and drawing the correct conclusions from these observations was really important, |
| in fact their survival depended on it. |
| It isn't known when people first started to observe the skies, |
| but at around 650 BC, |
| the Babylonians produced the first short-range weather forecasts, |
| based on their observations of clouds and other phenomena. |
| The Chinese also recognised weather patterns, |
| and by 300 BC, |
| astronomers had developed a calendar which divided the year into 24 festivals, |
| each associated with a different weather phenomenon. |
| The ancient Greeks were the first to develop a more scientific approach to explaining the weather. |
| The work of the philosopher and scientist Aristotle, in the fourth century BC, is especially noteworthy, |
| as his ideas held sway for nearly 2,000 years. |
| In 340 BC, |
| he wrote a book in which he attempted to account for the formation of rain, clouds, wind and storms. |
| He also described celestial phenomena such as haloes - |
| that is, bright circles of light around the sun, the moon and bright stars - and comets. |
| Many of his observations were surprisingly accurate. |
| For example, he believed that heat could cause water to evaporate. |
| But he also jumped to quite a few wrong conclusions, |
| such as that winds are breathed out by the Earth. |
| Errors like this were rectified from the Renaissance onwards. |
| For nearly 2,000 years, |
| Aristotle's work was accepted as the chief authority on weather theory. |
| Alongside this, though, in the Middle Ages, |
| weather observations were passed on in the form of proverbs, |
| such as 'Red sky at night, shepherd's delight; red sky in the morning, shepherd's warning'. |
| Many of these are based on very good observations and are accurate, |
| as contemporary meteorologists have discovered. |
| For centuries, any attempt to forecast the weather could only be based on personal observations, |
| but in the fifteenth century scientists began to see the need for instruments. |
| Until then, the only ones available were weathervanes - to determine the wind direction - |
| and early versions of rain gauges. |
| One of the first, invented in the fifteenth century, was a hygrometer, which measured humidity. |
| This was one of many inventions that contributed to the development of weather forecasting. |
| In 1592, the Italian scientist and inventor Galileo developed the world's first thermometer. |
| His student Torricelli later invented the barometer, |
| which allowed people to measure atmospheric pressure. |
| In 1648, the French philosopher Pascal proved that pressure decreases with altitude. |
| This discovery was verified by English astronomer Halley in 1686, |
| and Halley was also the first person to map trade winds. |
| This increasing ability to measure factors related to weather |
| helped scientists to understand the atmosphere and its processes better, |
| and they started collecting weather observation data systematically. |
| In the 18th century, the scientist and politician Benjamin Franklin |
| carried out work on electricity and lightning in particular, |
| but he was also very interested in weather and studied it throughout most of his life. |
| It was Franklin who discovered that storms generally travel from west to east. |
| In addition to new meteorological instruments, |
| other developments contributed to our understanding of the atmosphere. |
| People in different locations began to keep records, |
| and in the mid-nineteenth century, |
| the invention of the telegraph made it possible for these records to be collated. |
| This led, by the end of the nineteenth century, to the first weather services. |
| It was not until the early twentieth century that mathematics and physics became part of meteorology, |
| and we'll continue from that point next week. |