<P> Prior to the 18th century in Europe, people cooked over open fires fueled by wood . In the Middle Ages, waist - high brick - and - mortar hearths and the first chimneys appeared, so that cooks no longer had to kneel or sit to tend to foods on the fire . The fire was built on top of the construction; the cooking done mainly in cauldrons hung above the fire or placed on trivets . The heat was regulated by placing the cauldron higher or lower above the fire . </P> <P> Open fire systems had three major disadvantages that prompted an evolutionary series of improvements from the 16th century onwards: it was dangerous, it produced much smoke, and the heat efficiency was poor . Attempts were made to enclose the fire to make better use of the heat that it generated and thus reduce the wood consumption . An early step was the fire chamber: the fire was enclosed on three sides by brick - and - mortar walls and covered by an iron plate . This technique also caused a change in the kitchenware used for cooking, for it required flat - bottomed pots instead of cauldrons . The first design that completely enclosed the fire was the 1735 Castrol stove, built by the French architect François de Cuvilliés. This stove was a masonry construction with several fireholes covered by perforated iron plates and was also known as a stew stove . Near the end of the 18th century, the design was refined by hanging the pots in holes through the top iron plate, thus improving heat efficiency even more . </P> <P> The modern kitchen range was invented by Sir Benjamin Thompson, Count Rumford in the 1790s . As an active scientist and prolific inventor, he put the study of heat onto a scientific basis and developed improvements for chimneys, fireplaces and industrial furnaces, which led to his invention of the kitchen range . </P> <P> His Rumford fireplace created a sensation in London when he introduced the idea of restricting the chimney opening to increase the updraught . This was a much more efficient way to heat a room than earlier fireplaces . He and his workers modified fireplaces by inserting bricks into the hearth to make the side walls angled, and added a choke to the chimney to increase the speed of air going up the flue . The effect was to produce a streamlined air flow, so all the smoke would go up into the chimney rather than lingering and entering the room . It also had the effect of increasing the efficiency of the fire, and gave extra control of the rate of combustion of the fuel, whether wood or coal . Many fashionable London houses were modified to his instructions, and became free of smoke . </P>

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