520 



Phosphorescence. Photography. 



No. 54 258 



54 258 B. 1:4. 



54 258 A. 1:4. 



54259. 1:8. 



54 261. 1 : 6. 



54 260. 1 : 7. 



54.258. Case with 6 Phosphorescent Substances, shown open in Fig. A, and closed in 

 Fig. B 



The case contains six small tlat glass tubes sealed up and containing pulverulent substances of 

 different colours v. hick phosphoresce. In the lid there is a small wood slab let in under glass which 

 :-; coated with a paint which shines a brilliant violet. 



54.259. 7 Phosphorescent Substances, in eye tube, Figure. The back wall can be let 

 down 



54.260. NEW. Phosphoroscope after Lenard, F i g u r e, 1 adapted for single experiments and 

 for demonstration purposes (Hausser, Ztschr. f. Instrkd. 30, 1910, p. 278), with a pre- 

 paration holder with 6 preparations, a trough with quartz lid for powdery substances, 

 and a pair of tongs for holding any object; with 110 volt Direct Current Electric Motor, 

 tachometer and motor interrupter 



The phosphorescent body is illuminated by an electric spark generated from an induction coil 

 of 10 20 cm stroke between zinc electrodes, these electrodes being very rich in light exciting ultra- 

 violet phosphorescence. The duration between lighting and observation is quite small. The apparatus 

 is used when demonstrating from the side illustrated, and in individual experiments from the opposite side. 



54.261. Phosphoroscope after Becquerel, Figure (M. P., II, 1, Figs. 590592 [253]), on 

 firm stand 



54.262. - idem, large pattern, Figure, on cast-iron stand with toothed wheel 

 gearing 



52,046. Phosphoroscope arranged to fit Whirling Table: see Fig. 52,046, p. 284 



54,263. Phosphorescent Paint (Balmain's) can be used in conjunction with water or oil colour. 



Per half-kilogramme 



Photography. 



54,261. Folding Camera, Figure, for plates and films 9 x 12 cm, aluminium body covered 

 fine leather, with double bottom extension, thus allowing the hack lens alone to be 

 used. Objective adjustable laterally and vertically; three metal dark slides and intro- 

 duction to photography. Price with Extra-rapid Aplanat 



The objective has -.n iris diaphragm and shutter for time photographs of any dur.it ion and in 

 stantaneous exposures from '/too to 1 second. 'Ihe apparatus has a leather bellows, is fitted with a 

 good finder and is arranged for vertical and horizontal pictures. The picture can 1 e f.>russed either 

 by the scale or on the ground glass screen. Outside dimensions approx. 15.5 x 3.8 x 11.5 cm. For 

 Stands see Nos. 54 288 and 54 289. 



s. d. 

 0.12.0 



1. 0.0 



IS. 0. 



6. 0.0 



20. 0. 

 2. 0.0 



o. 15.0 



5. 10. 



Cl. 1446, 1447, 



3843, 1448, 5450. 



