Leonardo da Vinci proposed a solar furnace that would use mirrors to concentrate sunlight and produce intense heat.
Leonardo explored the optical power of reflected sunlight as part of his investigations into mirrors, burning glasses, and mechanical applications. By directing sunlight toward a small target, a large collection of mirrors could concentrate energy into a much hotter region than ordinary sunlight would create on its own.
The concept belongs to the long history of solar furnaces, which use concentrated sunlight for heating, melting, or chemical processes. Leonardo’s proposal was theoretical and did not become a working industrial furnace in his lifetime. His interest nevertheless shows how Renaissance engineers connected optical experiments with possible technologies.
A solar furnace is not the same as a solar still, which uses heat from sunlight to evaporate and condense water. Nor is it simply a sundial: a sundial measures time from the Sun’s position, while a furnace concentrates solar energy for heat.