James Watt observed the phenomenon of latent heat in his kitchen. One day, while watching the lid of a boiling kettle rise and fall, he realized that the steam escaping from the kettle was causing the pressure inside the kettle to decrease, which allowed the lid to rise. He also noticed that the cold water in the kettle began to boil more slowly as the steam escaped. This led him to conclude that steam was carrying away some of the heat from the water, and that the amount of heat required to turn water into steam was much greater than the amount of heat required to raise the temperature of the water. This observation later led Watt to develop the condensing steam engine, which was much more efficient than the earlier Newcomen engine.