502 



Spectrum Analysis and Synthesis. 



No. 54016 



; 



54019, 1:4. 



54022/27. 1:2-1:4. 



54 020. 1 : 2. 



54 029/54 031. 1 : 6. 



54 033. 1 : 6. 



54034. 1:8. 



54,016. Hollow Prism, trough form, with loose cover, with one compartment, 50 mm lorn:, 

 55 mm side . 



54.017. --idem, with two compartments 



54.018. - - idem, with three compartments 



54.019. - - idem, with four compartments, Figure 



54,020. Differential Prism (Double Trough) after Hallwachs, Figure, for determining 

 small differences in refractive ratios of liquids (Wied. Ann. 50, p. 577; Kohlrausch, 

 Lehrb. d. prakt. Phys., 10th. Edn., p. 260); all three sides traversed by the light are 

 of plate glass 



54,021. --idem, all three surfaces of plane parallel glass 



Wernicke Liquid Prisms, Figure: 



List No. 54,022 54,023 54,024 54,025 54,026 54,027 



Free Aperture, abt. mm 20x20 27x27 34x34 41x41 45x45 50x50 



2. 15. 3. 0. 4. 0. 5. 0. 8. 0. 13. 0. 



The prism is filled with cinnamic ethyl ether; it is mounted in wood to prevent temperature 

 variations: it is supplied with direct or deflected ray. 



54,028. - - idem, constructed round; can be taken apart for cleaning, aperture 30 mm . 

 In this type all cement is eliminated. 



Direct-Vision Prisms after Konigsberger, F i g u r e, filled with durable liquid (Ztschr. f. d. 

 phys. u. chem. U. 22, 1909, p. Ill; Phys. Ztschr. 9, p. 727): 



List No. 54,029 54,030 54,031 



Free Aperture mm 25 X 25 40 x 40 55 X 55 



1.10.0 2.10.0 4.10.0 



54.032. Gas Prism after Biot and Arago, for determining the absolute coefficient of refraction 

 of air and other gases,, with barometer gauge, brass mount and stopcock, for setting 

 up on the air-pump (Gan.-Atk. Fig. 536) 



54.033. Variable Angle Prism, Figure, for taking various liquids, simple pattern . . . 



54.034. - - i d e in, Figure, better construction, with degree graduation 



54.035. Prism Apparatus, Figure, with three prisms for demonstrating the achromatic 

 Prism and the Direct-Vision Prism (W. D. Fig. 298 [281]) 



Cl. 1338,^98. 



Diffraction Gratings: see Section "Diffraction of Light". 



s. d 

 0. 9.0 



0. 16. 



1. O.o 



1. 6. (I 



1.13.0 

 5. 0.0 



5. 0.0 



3. 0.0 

 13. 2.0 

 2. 10. 



1'. 8.0 



1341. 



