C. A. Steinheil Sohne, Mtinchen. 117 



The goniometer may also be used as a complete apparatus for 

 spectroscopie examinations. 



Large Spectrograph, 



for photographing the spectra of various illuminants. Mounted paral- 

 lactically, with adjustment for correcting the polar altitude, so arranged 

 that it may easily be placed in a horizontal position for photography 

 of terrestrial spectra. By moving a single screw it is possible to 

 follow the apparent motion of the sun in cases of continued exposures. 

 The slit telescope of 34 millimeter (15'") aperture and 32.5 millimeter (12'") 

 focus is fitted with Kruess's micrometer slit mechanism with symmetrical 

 movement of the platinum lips. There are three prisms of 50 degrees and 

 47 millimeter (21"') aperture; aplanatic photographic lens of 54 millimeter 

 (24'") aperture and 61 centimeter (22") focus; spectrum 20 millimeter (9"') 

 high and about 15 centimeter (5") long extending from line A to N. To ob- 

 viate loss of light as much as possible the objective and prisms are made 

 of glasses which absorb the smallest possible portion of the chemical 

 rays. A scale may be photographed together with each spectrum. Instantan- 

 'eous shutter for short exposures. The adjustable dark slide admits of 3 or 

 more exposures being made upon the same plate. 



Spectrum Apparatus according to Kirchhoff and Bunsen, 



first made in 1859, specially adapted for comparing the spectra of 

 two luminous sources. 



Fitted with a flint glass prism of 60, 2 telescopes of 27 millimeter (12'") 

 aperture and 24 centimeter (9") focus, magnifying 6 X> one f these being 

 fitted with slit mechanism. Scale telescope with 14 millimeter (6"') aperture 

 and 11 centimeter (4") focus. Cast iron foot. Accessories: 2 Bunsen burners, 

 2 pearl carriers with stand, description and tables for reducing values for 

 Bun sen's apparatus. t 



Hollow Prism, 



for determining the refractive indices of liquid media; capacity 10 to 

 11 and 15 to 16 cubic centimeter. Glass prism of 60 enclosed by 

 two perfectly plane surfaces. The prism has a cylindrical bore of 

 20 millimeter (9"') or 27 millimeter (12"') diameter passing through 

 it in such a way that its axis passes through the center lines of the 

 prism surfaces. A conical neck passes from the top of the prism to* 

 the cylindrical chamber and may be closed by an accurately fitting 

 stopper. 



Both openings of the cylinder may be closed by accurately fitting piano- 

 parallel glass plates. The liquid which is to be examined is introduced by the 

 conical neck. 



The covers may be removed by quickly heating the external surface. 

 To affix them it is sufficient to clean them thoroughly, to remove all traces 

 of dust and to press them upon the perfect surfaces of the prisms. 



