Chapter II: AN ESSAY ON VISION, briefly explaining the Fabric of the Eye, and

the Nature of Vision; intended for the Service of those whose Eyes are weak and impaired, enabling them to form an accurate Idea of the State of their Sight, the Means of preserving it, together with proper Rules for ascertaining when Spectacles are necessary, and how to choose them without injuring the Sight. 8vo. Boards, Price 3s. _Second Edition._