Leonardo da Vinci’s concentrated-sunlight experiment is commonly identified as a solar furnace. In the early 16th century, he proposed arranging many mirrors so that their reflected rays converged on one target, producing intense heat.
Leonardo considered the device for practical work such as melting metals or burning materials. The principle is straightforward: each mirror redirects sunlight toward the same focal region, raising its temperature far above that produced by ordinary sunlight.
His notebooks do not provide evidence of a working industrial furnace, and the precise arrangement and scale remain uncertain. Modern solar furnaces use large parabolic mirrors or heliostat fields with controlled focusing, but they apply the same optical idea.
This concept is not a steam engine or a telescope. It uses sunlight as the energy source and mirrors as concentrating elements, making it an early study of solar thermal technology.