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Fire was very important to man. He needed fire to ___(1)___ himself warm at night. He made use of fire to cook his food. He relied on fire to frighten away enemies and wild animals. In some parts of the world, he used fire to signal messages. Red Indians, for example, used fire to make smoke signals. In some other countries, fires helped people ___(2)___ away from danger.
Fire was also used to give light. ___(3)___ the invention of oil lamps, man utilised burning sticks as torches. Man hung small fires in wire baskets from posts to light the streets until he discovered gas and electricity.
One man even used fire to ___(4)___ the time. He invented a candle clock. He made a candle that took exactly twelve hours. Then he marked this candle in twelve equal parts. He lit the candle and could know the time ___(5)___ counting the number of parts left of the burning candle. However, the candle clock did not always work well. When there was a wind blowing on the candle, the flame burned too quickly.