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1 Jan 1820 Michael Faraday a londer liquefied a mmonia to cause cooling.
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prodotype called aspirator invented by Ives Mcgaffy
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by ancient they discoveredthat microwave oven cooks food in 1946 Dr Pency discovered something unusual he as next to a microwave and his choclate bar that was in his pocket melted.
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Willam Hoover manufactunig machines.hoover is still on of the markers of vacuum cleaner in the world
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now a days there are really good vacuum cleaners in the world