Dioptrica nova

Full title

Dioptrica nova: a treatise of dioptricks, in two parts, wherein the various effects and appearances of spherick glasses, both convex and concave, single and combined, in telescopes and microscopes together with their usefulness in many concerns of humane life are explained

A passage on p. 281 of part II tells of Molyneux's undated visit to Leeuwenhoek. It must have occurred in the summer of 1685 when Molyneux was in Holland.