No. 54 634. 



Paalzow Optical Benches. 



557 



54634. Large Paalzow Optical Bench, 1 : 7. 



Fitted with the undermentioned accessories and auxiliary apparatus No. 50,982, 50,986, 54,022, three of No. 54,180, 

 Nos. 54,627, 54,637, 54,641, 54,644, 54,648, 54,650, 54,653, 54,664, 54,665 and 9 additional preparations. 



6 of which can be adjusted vertically by rack and pinion; one of these can be adjusted laterally by a 

 micrometer screw for carrying out interference experiments. 



The following experiments are possible when an appropriate selection of the accessories Nos. 54,636 

 to 54,669 is made. 



1. Double refraction with one or two double refracting prisms, Fig. 54,635 d. 



2. Breaking up of the unpolarised light into 2 or 4 polarised rays by double-refracting prism. 



3. Polarisation by using a Nicol and a double-refracting prism, Fig. 54, 635 b. 



4. Polarisation by a Nicol prism and a column of glass plates. 



5. Polarisation by a Nicol prism and a black mirror. 



6. Polarisation by a glass plate column and a black mirror, Fig. 54, 635 c. 



7. Polarisation by 2 Nicol prisms in parallel light. 



8. Polarisation by 2- Nicol prisms in strongly converging light, for monaxial and bi-axial crystals, 

 Fig. 54,635 a. 



9. Explanation of the scientific and technical polarisation apparatuses; Soleil's wedge compensation, 

 colour apparatus and half-shadow apparatus by means of Lippich's polariser. 



10. Demonstration of interference and diffraction phenomena. 



11. Demonstration of spectrum phenomena by a gap, a collimator lens and a large direct-vision prism, 

 Fig. 54,635e. 



12. Demonstration of Microscopic phenomena in polarised light, Fig. 54,635 f. 



13. Projection 01 microscopical preparations. 



As luminous source use can be made of a heliostat, of one of the projection apparatrs listed 

 under Nos. 50,730 50,744, 50,783 50,806, or of the Megadiascopes Nos. 9500 9519. The most 

 advantageous sources to use for these experiments are the apparatus having an electric arc lamp or, 

 perhaps, limelight. The path of rays can be followed freely by the audience and the entire arrange- 

 ment of lenses, objects, etc. is such that an image is first cast on the projection screen in unpolarised 

 light, the objects then appearing in polarised light when the polarisers are inserted. 



Supplied with the apparatus are: 



6 Stands, with up and down adjustment, five of these with rack and pinion. 

 1 Stand with lateral screw displacement for interference experiments. 

 1 Water Trough ( 2. 0. 0) for continuous cooling, for condensers to 122 mm diameter (when using 



projection lanterns having larger condenser use should be made of larger troughs at an extra 



price of 0. 10. 0, see List No. 50,977). 

 1 Bi-concave Lens in mount ( 1. 5. 0) for producing parallel rays (when ordering the size of condenser 



of the lantern should be given). 

 1 Rotary Object Holder ( 1. 5. 0). 



1 Open Objective ( 1. 10. 0). 



2 Bearings for the Nicol prisms ( 0. 15. 0). 



2 Condensers ( 4. 0. 0) for producing strongly converging rays. One of these condensers is fitted with 

 preparation holder. 



If desired, the accessories, together with any auxiliary parts ordered at the same time, are fitted 

 in a durable box, at lowest possible price. 



Auxiliary parts for definite optical experiments: see Nos. 54,636 54,669. 



s. d. 



01. 2S9. 



