No. 53 809. 



Concave Mirrors. Plane Mirrors. 



479 



53 806. 1 : 8. 



53 807. 1 : 7. 



53809,53806. 1:6. 



53.806. Demonstration Goniometer after Weinhold, of. F i g u r e, large Pattern (W. D., I s. d. 

 Figs. 265267 and 286288 [251253 and 270271]) 118. 0. 



The Goniometer can be used horizontally and vertically. It is used for more accurate experiments 

 on reflection, refraction and colour-dissipation, for determining the angles of prisms and refractive 

 indices by Fraunhofer's, Meyerstein's or Listing-Abbe's Method, as a Goniometer and Spectrum Appa- 

 ratus. Height, 50 cm; diameter of circle, 55 cm. The apparatus is graduated in whole degrees. 



The accessories comprise a centering plate for crystals, a plane mirror in mount, a water-vessel 

 with gap, a gap with illuminating mirror, one index, two lenses, one collimator tube, one observing 

 telescope, one prism of flint glass, 45 mm side, and a key. All parts placed in a box. 



53.807. - - i d e m, with a second graduation on brass in whole degrees and with vernier 

 reading, for subjective observations, Figure 21. 0. 



53.808. - - the same apparatus as No. 53,806, but without Telescopes, without prism or box; 

 cannot be used as a Spectrometer, etc 15. 0. 



53.809. Ocular with Gap for the observation telescope, and Symmetrical Double Gap after 

 Vierordt (v. Konkoly, Handbuch der Spektroskopiker, Halle, 1890, pp. 388 390), for 

 the collimator tube 'of the Weinhold Goniometer No. 53,806 or 53,807 (cf. F i g. 53,809), 



in order to enable the apparatus to be used in addition as a Spectrophotometer . . i 7. 10. 



Ocular and double gap can be set up forthwith on the observation telescope or collimator tele- 

 scope supplied with NOB. 53,806 or 53,807. The illustration shows the demonstration goniometer 

 arranged in the manner in which it is used as a Spectrophotometer. 



Cl. 6057, 5317, 

 3076. 



