In the course of his treatise On Burning Mirrors, he intended to facilitate the construction of surfaces to reflect light to a single point, he described the string construction of the ellipse and assumed a property of ellipses not found in Apollonius of Perga's Conics: the equality of the angles subtended at a focus by two tangents drawn from a point.
In his treatise "On Burning Mirrors," he aimed to create surfaces that reflect light to a single point, he described the string construction of the ellipse and assumed an attribute of ellipses not found in Apollonius of Perga's Conics: the equality of the angles subtended at a focus by two tangents drawn from a point.