46 A. Kriiss. Hamburg. 



The Scale has a length of 3 meters (9' 10"), it is divided in half 

 centimeters. If desired also a scale of intensity measures may be added. 



By the arrangement of Luminer and Brodhim's photometer the images 

 of the two sides of the screen, which are perfectly similar, are reflected 

 in such a manner that the image of one side appears as a disc completely 

 encircled by the image of the other disc. These differences in the intensity 

 are indicated by a distinct line: with equal intensities this line must disappear. 



Bunsen's Photometer revolving on a divided circle, for 

 measuring the intensities corresponding to different angles of emission. 



Photometer Mirror with divided circle. 



It is inclined at 45 to a horizontal axis and is intended for photometric 

 evaluation of the intensities of light emitted in different directions by fixed lights. 



Fig. 7. Fiff. 8. 



Photometric Stand for Incandescent Lamps. (Fig. 7.) 

 The incandescent lamp revolves on two axes at right angles to 

 one another and its position may be read off. 



Optical Flame Gauge. Original Construction, for accurately 

 measuring the length of a flame of a candle or other light. (Fig. 8.) 



(Hefner's) Amyl-acetate lamp with optical flame gauge. 

 Beside these instruments the following instruments made by this firm are 

 being exhibited in other departments: 



Spectroscope and Colorimeter, which will be found among the 

 apparatus composing the Hygienic Laboratory exhibited by the Hygienic 

 Institute of the University of Berlin. 



Projection Apparatus and Lantern Slides forming part of the 

 Educational Appliances, exhibited by the Prussian Ministry of Public Instruction. 



