Of Monsieur de Sons progress in working parabolar glasses

Since what was mentioned in the immediately precedent tract, touching Monsieur de Son's noble attempt of grinding glasses of a parabolical figure, the publisher of these papers hath himself seen two eye-glasses of that shape, about one inch & a half deep, and one inch and a quarter broad, wrought by this eminent artist with a rare steel-instrument of his own contrivance and workmanship, and by himself also polished to admiration.