Physicist and geologist, born in Geneva, Switzerland. Professor of physics and philosophy in Geneva, traveled to Germany, Italy, and England. He was the first traveler to ascend Mont Blanc (1787). He studied mineralogy, botany, geology, and meteorology; his observations are recorded in Voyages dans les Alpes (1779–96). He developed the hair hygrometer and other instruments. The term "geology" is attributed to him.

His work contributed to knowledge about the importance of soil-derived elements absorbed by plants. He is credited with demonstrating the essentiality of C, H, O, and N for plant growth.