Experiments Upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and of Injuring It in the Shade and at Night

In 1779, Jan Ingenhousz published Experiments upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and of Injuring It in the Shade and at Night. This work detailed his discoveries about photosynthesis.12

Ingenhousz found that light is essential for plants to restore air, a process that only occurs in the green parts of the plant. He observed that plants absorb carbon dioxide and release oxygen in sunlight. In darkness, plants release carbon dioxide, but the oxygen production in sunlight far exceeds this release. This built upon the earlier work of Joseph Priestley, who had shown plants could restore air that supported combustion.32