496 



Refraction. Total Reflection. 



No. 53 907 



53 920. 1 : 5. 



53 924. 1 : 8. 



. s. (1. 



53.907. Cylindrical Lens 60 mm diameter, in mount, on stand 1. 4. 



53.908. idem, 80 mm diameter 1. 10. 



53.909. 2 Convex Lenses 80 mm diameter and 500 mm focal length, on tall stands; can be ; 



used for a number of experiments, together 1. 10. 



Hollow Lenses, bi-convex, with lateral opening for introducing liquids: 



List No. 53,910 53,911 53,912 53,913 53,914 



Diameter mm 50 80 105 130 155 



f 0.5.0 0.7.0 0.8.0 0.10.0 0.13.0 

 - idem, plano-convex: 



List No. 53,915 53,916 53,917 53,918 53,919 



Diameter mm 50 80 100 130 160 



0.5.0 0.7.0 0.8.0 0.10.0 0.13.0 



53.920. Lens Stand, Figure, in which can be mounted any lens from 25 to 50 mm diameter 



53.921. --idem, for lenses from 50 to 100 mm diameter 



53.922. idem, for lenses from 100 to 150 mm diameter 



53.923. Hollow Concave Lens (plano-concave) for use as a condensing lens under water 

 (W. D., p. 384) 



53.924. Lens Apparatus after Dr. Zwick, Figure. (Dr. Zwick, 150 optische Versuche usw., 

 pp. 49 et seq. ; see No. 53,928), with lenses 50 mm diameter, for showing the action 

 of condensing and dispersing lenses and the camera obscura, the human eye and 

 spectacles 



The apparatus consists of one optical bench of 60 cm useful length, 1 Lens Holder; 2 curved 

 Glass Disks, for representing the cornea and the iris, with the pupil, of the eye; 3 convex Lenses of 6, 

 8 and 11 cm focal length, in mount; 1 bi-convex Lens of 30 cm focal length with mount and haft; 

 1 bi-concave Lens of 15 cm focal length, with mount and haft; 1 Stage; 3 Stands; 1 Ground Glass 

 Disk with mount; 1 Wire Cone; 1 Disk perforated in centre, with rotary disk and various diaphragm - 

 apertures; 1 Ring for stretching paper; 1 small Tripod. 



53.925. - - idem, larger Pattern; diameter of Lenses 80 mm 



53.926. Optical Apparatus ufter Dr. Zwick, for the Fundamental Theories of Optics, with optical 

 bench 2 m long and the accessories listed below, which also contain the accessories of 

 the lens-apparatus after Dr. Zwick, No. 53924 (Dr. Zwick, 150 optische Versuche /m 

 Veranschaulichung der Grundlehren der Ausbreitung, Spirgeliing und Bret-hung des 

 Lichts; sec No. 53,928) 



The constituents of the apparatus are: 1 optical Bench; 1 Lens Holder (as No. 53,924); 2 curved 

 Glass l>isks representing the cornea and the iris, with the pupil, of the human eye; 3 bi-conve\ I.rn-"- 

 of 9, 11, 15 cm focal length, with mounts; 1 bi-convex Lens of 30 mm focal length, with mount and 

 haft; 1 Bi-concave Lens of 15 cm focal length with mount and haft; 1 Stage; :> Stands; 1 Ground Glass 

 Disk with mount; 1 Wire Cone; 1 centrally pierced disk with pivoting disk and different diaphragms 



1. 0. 

 1. 4.0 

 1. 10. 



0. 10. 



4. 0.0 



(i. 0. 



11.0.0 



Cl. 1354. 4002. 



