No 50 985. 



Accessories for projections. 



175 



50 976. 1 : .V 



50978. 1:5. 



50983. 1:8. 



50 984. 1 : 6. 



50985. 1:9. 



50.974. Slider with stand, for setting up Nicol prisms, lenses, etc. on the optical bench of s - d- 

 the projection apparatus : 0. 10. 



It is advisable to order, say, from 3 to 6 such sliders, not only in view of the fact that a number ; 

 of sliders have to be used simultaneously for many experiments, but also in order that diaphragms, '', 

 slits, lenses, etc. which are placed in them may be inserted ready for use before the experiment, thus 

 allowing the latter to be made expeditiously. 



50.975. do., -with lateral motion of the stand by screw \ 0. 18. 



Cooling Tank, for continuous-flow cooling by water (Figure), fitted with good plate 

 glasses, also with handle for inserting in a slider (No. 50,974). 



List No. 50,976 50,977 



Diameter of Condenser 102 and 122 152 mm 



2. 0. 2. 10. 



The cooling vessel is absolutely necessary in polarisation experiments or when introducing micro- 

 scopical preparations, provided, of course, the projection apparatus has no cooling vessel between the 

 condensers. 



50,978. Universal Stand, Figure, with clamp adjustable in every direction, for small 

 objects to be projected 



Bi-concave Lens, in mount, with diaphragm and handle, for obtaining parallel rays. 



List No. 50,979 50,980 50.981 



For Condensers 102 122 152 mm diameter 



Prices 16 s. d. 18 s. d. 1. 0. 



50.982. Collimating Lens, 100 mm diameter and about 33 cm focus, for spectrum experiments; 

 in mount, with diaphragm and haft 



This lens is used for obtaining a true slit image when a prism is employed. 



50.983. Diaphragmic Disc, Figure, rotatory, with handle, with 9 apertures, for diffraction 

 phenomena with sun or electric light 1. 4. 



50.984. Iris Diaphragm, Figure, max. aperture 10 cm, with haft for sticking in the stands 



of the optical benches 1. 15. 



50.985. Adjustable Slit with diaphragm and handle, Figure ; 0. 18. 0- 



0. 12. 



0. 18. 



CI. 5451. 2721. 

 277. 5453. 



