English chemist Joseph Priestly recently demonstrated that plants give off oxygen. Ingenhousz expanded this research by noting that plants not only give off oxygen, but absorb carbon dioxide. He also discovered sunlight was an important factor. During the day, plants absorb carbon dioxide and release oxygen. During the night, or when sunlight was not available, he found the process reversed. Plants absorb oxygen and release carbon dioxide in the dark. This was the first step to understanding the process of photosynthesis.
Ingenhousz believed the water absorbed by plants and converted into 'vegetation' and oxygen. Find out more about photosynthesis and what else occurred on this day in science history.