No. 53 655. 



Photometers. 



469 



53 652. 1 : 2. 



53 653. 2 : 5. 



53 654. 1 : 9. 



53 655. 1 : 14. 



53.650. Flicker Photometer Head, Figure, with sector disc 



The Flicker Photometer is based on the fact that two illuminated surfaces coming alternately 

 before the eye only show a flickering if differently illuminated. 



53.651. -- idem, with rotating flicker body, Figure, with inclining device and degree 

 graduation, for measurements from different directions 



53,652. Lummer-Brodhun Photometer Head, 

 mentenkunde 9, 1899, p. 41) 



with stand, Figure (Ztschr. fiir Instru- 



53.653. - - idem, for viewing perpendicular to the luminous sources, Figure . . . . 



53.654. Photometer after Leonh. Weber, Figure, with complete accessories, in polished 

 wood box 



The photometer is based on the comparison of two illuminated ground discs, one of which is 

 arranged so as to be movable in a horizontal tube; the tube perpendicular to the latter tube, and 

 containing the other ground disc, contains a Lummer-Brodhun Cube, is arranged to rotate, and can 

 be conveniently focussed on the luminous source to be investigated. A graduated arc permits the 

 angle described to be read off. As comparison light source use is made of a small benzine lamp 

 having a flame-height of 20 mm; the correct height can be read off on a scale pasted on plate glass, 

 and can be adjusted by a rack. 



53.655. Photometer after Eousseau, Figure, for photometering arc lamps in various 

 directions (Elektrot. Ztschr. 8, 1887, p. 356) 



Cl. 1216, 3385, 

 5442, 1219. 



s. d. 

 5. 0.0 



6. 15. 



5. 0.0 



6. 5.0 



20. 0.0 



9. 0.0 



