1226 



Megadiascope. 



I s. d. 



9602. Interference Prism, with diaphragm and holder 0.16.6 



9603. Fresnel Ocular Micrometer, alone, Fig. 22, p. 1214, for measuring the Interference 



bands, on stand 



5. 0.0 



9604. Short-focus lens, on stand, for observing the interference bands [0.15.0 



For setting up the apparatus 2 sliders with stands, No. 9523, and 1 stand, No. 9524, 

 are necessary. 



Projection in Natural Colours by Ives's Method. 



9605. Projection Chromoscope (Ives's) arranged for the Megadiascope, for showing photographs 



in natural colours. Fig. 23, p. 1214 ' 13. 0.0 



The mode of working of the apparatus is, that three diapositives which correspond to the funda- 

 mental tints red, green and blue-violet of the object photographed, are combined on the screen into an 

 image with the original colours, by the apparatus in question. The apparatus can also be used for a 

 number of other experiments such as the demonstration of the mixed and complementary tints, absorption 

 phenomena, etc., etc. 



9606. Photographs, 3 diapositives on one plate 0. 7. 



List of photographs on application. 



Projection in Natural Colours by Diffraction. 



9607. Diffraction Chromoscope, Fig. 24 on p. 1215, for obtaining coloured images by means 

 of trichrome photographs produced from diffraction gratings by Wood's process. The 

 apparatus is made to suit the Megadiascope. Price, exclusive of optical bench . . . 1 o. 0. 



The outfit consists of 1 light-excluding folding box with 1 simple slit; 1 photo holder with change 

 frame, 1 bi-concave lens, 1 slit (with diaphragm) adjustable in height and width, 1 achromatic objective 

 with diaphragm, 2 riders with collar raised and lowered by rack and pinion, and 1 rider with stand: 

 also 6 photographs on plates (size of image 6,5 cm.). 



Complete description forwarded on application. 



Projection with the Cinematograph. 



9608. Cinematograph (F i g. 25, p. 1215), new model, well constructed, with objective of 



5 cm. focal length 7. 10. 



The new model differs from that illustrated. At a distance of 5 m. the apparatus gives a picture 

 1,65 m. wide. The spools are suitable for up to 100 meters (328 feet) film. 



9609. Films, 16, 24, 32 and 48 m. in length, suitable for the cinematograph listed. Price 



per 1 meter (3.2 feet) 0. 3. 



The prices of the individual films differ according to the length. List on application. The price 



for tinting each meter (3.2 feet) is 2 s. 



We can also supply larger cinematographs for spools 



capable of taking 200 meters (656 feet) film, and shall be 



pleased to quote prices for these on application. 



9610. Cinematograph, compactly constructed % 4. 10. 



9611. - - d o., with arrangement for taking cinematographic pictures 8. 5. 



To this apparatus pertain 3 slides each for 20 meters (65.6 feet) of film, sufficient for an exposure i 

 of about 2 minutes. A perfectly firm stand is necessary in this connection. 



9612. Film Strips, for taking negatives and positives Per meter 0. 0. 8 



9613. Firm Tripod Stand 0. 10. 



List of Films suitable for use in connection with these cinematographs free on 

 application. 



Production of a narrow Cone of Rays 



for demonstrating the Lissajous Curves, the Oscillograph, etc. 



9614. Diaphragm, with fine aperture, and with holder 0. 6. 



9615. Lens, 80 mm. diameter and 170 mm. focal length, with diaphragm and holder. . . ; 0.15.0 



Switchboards and Resistances. 



9616. Switchboard for connecting up the Megadiascope, F i g. 40, for 110 Volts and 30 amperes s. d. 

 maximum, with adjustable series resistance behind the board 9. 0. 



The switchboard contains: 2 fuses, 1 ammeter, 1 regulating resistance, contact circuit with regu- 

 lating handle, 1 double-pole switch and 1 plug box. The switchboard consists of an iron framework 

 with a marble slab as front wall. The framework contains the resistance coils of the current regulator. 

 By means of the regulator the current of the electric arc lamp can be regulated between 15 and 30 amperes. 



