No. 54 576. 



Diffraction Apparatus. Diffraction Gratings. 



549 





54 558. 2 : 3. 



i 



54 568. 1 : 3. 



MAX KOHL. CHEMNITZ 



54 561. 1 : 2. 



54 566, 54 568. 1 : 2. 



54 576. 1 : 



54.560. Photographed Grating after Xobert, 3 cm wide with lines 3 cm long; 1000 lines to 

 1 cm , 



On account of its brightness this grating is well adapted for demonstration purposes, but not 

 for accurate measurements. 



54.561. Copy of a genuine Rowland Grating, Figure, 50 x35 mm area of grating, in case 



54.562. - - idem, smaller, 25 X 20 mm area of grating 



54.563. - - idem, between two glass prisms inclined 7 and 32 mm square, Figure . 



54.564. Photographed Diffraction Grating, cemented as a lantern slide between glass plates, 

 115 lines to the millimetre, area 63 square millimetres 



54,565. - - idem, photographed area 25 x 25 mm 



54,566. Diffraction Grating after Henry A. Eowland, with 14,438 rulings to one inch, Figure, 



plane or concave, of the highest perfection 



As a rule we keep a number of such gratings in stock; kindly state requirements. 



Stands for Rowland's Diffraction Gratings, Figs. 54,568, accurately constructed: 



List No. 54,567 54,568 54,569 54,570 54,570 a 

 Suitable for Gratings of 1.4" 2.5" 4" 5" 6" 



2.10.0 3.10.0 4.0.0 4.10.0 5.0.0 



Fig. 54,566 shows the stand with the grating set up on it. 



- idem, simple pattern : 



List No. 54,571 54,572 54,573 54,574 54,574 a 



Suitable for Gratings of 1.4" 2.5" 4" 5" 6" 



0. 12. 0. 18. 1. 4. 1. 10. 1. 16. 



* 54,575. Phase Reversing Plate, after E. W. Wood, consisting of a glass plate covered with a, 



large number of concentric rings of different fineness and acting as a lens, 180 cm focal 

 length (Phil. Mag. 1898, p. 511) 



The plate of 180 cm focal length gives an image of the arc at a distance of approximately 2.5 m 

 from an arc light regulator at a distance of approx. 4 m. The plate of 40 cm focal length can be 

 used as landscape objective with the aid of a weak convex lens. 



* 54,576. Circular Photographed Grating, Figure, graduated area 76 mm diameter, about 



200 lines to the millimetre 



If an image of tlie arc of an electric projection lamp is cast on the screen and if the circular 

 grating is placed on it centrally in front of the objective, an annular rainbow results. 



s. d. 

 0.18.0 



1. 4.0 

 0.15.0 



2. 0.0 



0.10.0 

 0. 5.0 



Price on 

 appli- 

 cation 



# Can be used with the Projection Apparatus. 



Cl. 1588, 3685, 

 1591, 1589, 



0.10.0 



1. 0.0 



1590, 

 3686. 



