In each question, the first and the last sentences of the passage are numbered S1 and S6 respectively. The rest of the passage is split into four parts. These four sentences are jumbled. Read the sentences and identify their correct and logical order.

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S1: Forecasting the weather has always been a difficult business.
P : During a period of drought, streams and rivers dried up, the cattle died from thirst and were ruined.
Q : Many different things affect the weather and we have to study them carefully to make accurate forecast.
R : Ancient Egyptians had no need of weather in the Nile Valley hardly ever changes.
S : In early times, when there were no instruments, such as thermometer or the barometer, man looked for tell-tale signs in the sky.
S6: He made his forecasts by watching flights of the birds or the way smoke rose from fire.
The Proper sequence should be: