II. OPHTHALMOLOGICAL. 791 



3707. Dr. Lionel Scale's Demonstrating Ophthalmo- 

 scope. Thomas Hawksley. 



3708. C. J. Oldham's First Ophthalmoscope, with one 

 diaphragm at back of mirror to carry lenses. 



Thomas Hawksley. 



3709. C. J. Oldham's Second Ophthalmoscope, with 

 three diaphragms. Thomas Hawksley. 



3710. Couper's Ophthalmoscope, with five discs. 



Thomas Hawksley. 



371Oa. New Optometer, with double refracting lens of calc- 

 spar, give double readings, and greater precision in determining 

 the distance of sight. Professor Carl Wenzel Zenger, Prague. 



3711. R. Brudenell Carter's Perimeter for ascertaining 

 the boundary of the field of vision and the area of the blind 

 spot. Thomas Hawksley. 



3712. Perrin's Artificial Eye Apparatus. T. Hawksley. 



3713. Dr. Badal's Optometer. M. Roulot, Paris. 



3714a. Messrs. Perrin and Mascart's Optometer. 



M. Roulot, Paris. 



3714b. Dr. Badal's Perimeter. M. Roulot, Paris. 



3714. Dr. Giraud Teulon's Binocular Ophthalmoscope. 



M. Roulot, Paris. 



3715. Boxes of Metrical, Spherical, Cylindrical, and 

 Prismatic Glasses. M. Roulot, Paris. 



3716. Various kinds of Optical Glass. Weslein, Paris. 



3717. Set of Lenses for Trying the Sight. 



W. Campbell 3? Co.'s successor, T. Wohlers, Hamburg. 



3717a. Box with Specimen Spectacles for Oculists. 



W. Campbell's successor, F. Wohlers, Hamburg. 



3719. Metrical Ophthalmoscope, of Dr. de Wecker. 

 In one zone are placed 20 convex glasses ascending gradually 

 from 0*50 to 10 metrical dioptric. To obtain the concaves, a 

 concave lens is interposed, more powerful than the maxima of 

 the convex glasses (10J dioptrics), and by turning the wheel' a 

 descending series of O'oO to 10^50 concave dioptrics is obtained. 



M. Cretes, Paris. 



3720. Weber's Photometer and Chromometer. 



Dr. Weber, Darmstadt. 



3721. Weber's Chromoptometrical Tables. 



Dr. Weber, Darmstadt* 



