History of Chemistry


What is the theory of phlogiston?

In 1667, a scientist named Johann Joachim Becher introduced the theory of phlogiston as an explanation for the various observations scientists had made regarding combustion. These observations include the fact that some objects can burn while others cannot, and that a flame in a sealed container can go out before the combustible material is consumed. Becher proposed that a weightless (or almost weightless) substance called phlogiston was present in all materials that could burn and that this phlogiston was the substance being given off during combustion. If a candle placed in a closed container went out, Becher said this was because the phlogiston from the candle was moving into the air and that the air could only absorb a certain concentration of phlogiston before it became saturated and could no longer absorb more phlogiston from the candle. Another tenet of this theory was that the purpose of breathing was to remove phlogiston from the body. Air that had been used for combustion couldn’t be used to breathe then because it was already saturated with phlogiston.


This is a web preview of the "The Handy Chemistry Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App