548 



Interference and Diffraction. 



No. 54 544 



54 544 A. 1:6. 



54 544 B. 1:4. 



54 547. 1 : 10. 



53,907. Cylindrical Lens, in mount, on Stand, 60 mm diameter, for observing the Fresnel 

 diffraction bands (M. P. II, 1, p. 793 [944]) 



53,908. --idem, 80 mm diameter 



54.544. Diffraction Apparatus, Figs. A and B, consisting of an achromatic telescope of 30 mm 

 aperture, on Stand 



The following pertain to above: 1 gap attachment with micrometer screw, 2 attachments with 

 rotary diaphragm discs having the following apertures: 1 round hole, 2 round holes, 3 round holes, 

 4 round holes, 1 triangle, 1 rectangle, 1 rhomb, 1 row of holes, 1 sieve, 1 double gap, 1 triple gap, 

 1 wire grating, 1 grating on glass (1 cm in 100 parts), 2 rhombs. The sets of gaps and diaphragms 

 are contained in a case, Pig. B. 



54.545. - - idem, with larger telescope having aperture of 40 mm, gap with micrometer 

 screw and divided drum, fitted with finer glass grating and a larger number of diaphragms 



In addition to the diaphragms listed in previous item, this apparatus contains: 1 rotary dia- 

 phragm disc with: 1 hole 0.4 mm diameter, 1 crossed wire grating, 1 needle, 1 hair, 1 small rod, 1 sharp 

 edge, 1 small rod half covered with mica for showing the distortion of the interference bands. 



54.546. Nickelled Metal Sphere, on stand, for producing a luminous point by reflection of 

 sunlight 



54.547. Diffraction Apparatus for determing the wave length of light, after Hoffmann, 

 Figure (Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 32), with three coloured discs 



The apparatus consists of an optical bench fixed on a stand and rotating about a horizontal 

 axis, on which are placed a grating with observation tube and a diaphragm having a screen. These 

 apparatus are capable of movement along the bench. The diaphragm consists of 3 parallel 0.5 mm 

 wide gaps of different length placed at distances apart of 10 mm. Covers with coloured discs can be 

 placed on the diaphragm. Three of these coloured discs (red, green and blue) are supplied with each 

 apparatus. 



54.548. - - idem, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 135) . . . 



54.549. - - idem, for Students' Use, after Grimsehl, comprising Xernst Lamp on stand, 

 diaphragm with aperture, 4 coloured glasses, small optical bench, glass micrometer 

 (E. Grimsehl, Ausgewahlte physikalische Schuleriibungen, Figs. 8 10) 



Glass Gratings: 



List No. 54,550 54,551 54,552 54,553 54,554 54,555 



Lines to 1 cm 50 100 200 300 500 1000 



0.5.0 0.7.0 0.14.0 1.2.0 1.16.0 2.16.0 



54,556 54,557 



2000 3(lO<) 

 3. 10. 4. 0. 



54,558. Double Grating, in Brass Mount, rotary one above the other, Figure, 1 mm in 



7.10.0 



11. 0.0 



0.16.0 



6. 0.0 



2. 10. 



2. 15.0 



0. 18.0 



13 parts 

 54,559. Wire Grating i 0. 10.0 



Cl. 1585, 1586, 1584 



