No. 54531. 



Interference Mirrors. Adjustable Gaps. 



545 



54 523. 1 : 4. 



54525 (54540). 1 : 4. 



54 530. 1 : 7. 



54 531. 1 : 6. 



* Fresnel's Mirror Apparatus, Figs. 54,517 A and B, with two black ground mirrors; one mirror s. d. 



centered by three screws, the other adjustable relatively to the others by fine screw, 

 on Stand: 



List No. 54,517 54,518 54,519 



Size of Mirrors mm 30x40 40x50 50x60 



2.2.0 2.8.0 3.0.0 



Fig. 54,517 A shows the front, and Fig. 54,5178 the back of the interference mirror. 



* -- idem, simple, with cemented, ground mirrors: 



List No. 54,520 54,521 54,522 



Size of Mirrors mm 30x40 40x50 50x60 



1.4.0 1.12.0 2.0.0 



* 54,523. Interference Mirror after Fresnel, Figure, with parallel micrometer motion, micro- 



meter screw with drum and graduation, on stand, most carefully constructed .... 7. 0.0 



* 54,524. - - idem, without micrometer motion 4. 16. 



* 54,525. Ocular Micrometer after Fresnel, Figure, for measuring interference bands, on 



stand 6. 0.0 



54,526. Fresnel's Mirror for Students' Use, after Grimsehl, for determining the wave length 

 of light, with gap, micrometer graduation and two mounts (E. Grimsehl, Ausgewahlte 

 Schuleriibungen, Figs. 2 and 3) 0.14.0 



Lenses: see No. 53,932 b. 



Adjustable Gaps: see Nos. 54,53054,535. 



* 54,527. Interference Apparatus after Grimsehl, constructed on the Lloyd single mirror prin- 



ciple, thus doing away with adjustment of the mirrors. The direct and the reflected 

 image of the gap are used together for interference (Ztschr. f. d. phys. u. chem. U. 20, 

 1907, p. 217). The gap with micrometer screw for adjusting and screw for narrowing 

 and widening are on stand 3. 10. 



54.528. Screen with ground glass disc and millimetre graduation for determining wave length; 

 for use with red and blue glass discs, and especially with the preceding Grimsehl Inter- 

 ference Apparatus (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 218) 1. 10. 



54.529. Interference Apparatus after Classen, for demonstrating the phenomena before a 

 large audience ; interference is produced by reflection on two glass plates (Hassack-Rosen- 



berg, Projektionsapparate, p. 230; Classen, Natur des Lichts, Fig. 9) 2.10.0 



54.530. Adjustable Gap, Figure, with diaphragm screen, on stand, cf. No. 50,985 ... 1. 3. 



54.531. -- idem, with Micrometer Screw, Figure, on Stand, cf. No. 50,986 1.13.0 



* Can be used with the Projec- Small transparent Projection Screen: 



tion Apparatus. see No. 51,003, p. 179. ii02.326.32o. 35 



