Night View of Coalbrookdale

Painted by Loutherbourg (1801)

An Experiment on the Air Pump

Painted by Wright of Derby (1768)

• Phlogiston can element believed to be the "source of burning"?
  
  
• Chemists of the time believed that combustion (including decay and animal respiration) occurred because phlogiston contained within substances escaped into the air.
  
  
• When a mouse was kept in a sealed container and died, it was thought that the air had become saturated with phlogiston.
  
  
• Scientists searched for ways to purify air filled with phlogiston they observed that a potted mint plant remained healthy in a glass container filled with such "contaminated" air.
  
  
• They believed that plants had the power to clean the air, and when a plant and a mouse were placed together in the same glass container, the mouse survived much longer.
  
  

Priestley's Experiment (around 1774)

History of Science and Technology (The Open University of Japan, Course Material 12492-1-9911)