Experiments on vegetables, discovering their great power of purifying the common air in the sun-shine, and of injuring it in the shade at night. To which is joined, a new method of examining the accurate degree of salubrity of the atmosphere.

Discovery of photosynthesis. Ingen-Housz showed that the green parts of plants, when exposed to light, fix the free carbon dioxide of the atmosphere, but that in darkness plants have no such power. Thus he proved that animal life is dependent ultimately on plant life, a discovery of fundamental importance in ecology.