No. 54 501. 



Telescopes. Interference of Thin Sheets. 



543 



54500. 1:1 



54501. 1:3. 



astronomical ocular, with smoked glass, stand for erecting at the height of the table, 

 and box 



If desired, instead of supplying the terrestrial eyepiece, 2 astronomical eyepieces (power 24 and 

 96 respectively) are provided with the instrument. The axial system is arranged for a mean polar 

 height of 50, but the polar height can be varied between 48 and 53. 



54.482. Graduated Circle for right ascension and declination, reading to 1 Extra 



54.483. Ocular Prism for observing objects in the neighbourhood of zenith 



54.484. Astronomical Eyepiece for powers 32, 72, or 120 Each 



Telescopes, mounted parallactically and balanced, with metal stand, F i g. 54,488, for setting 

 up at table height, with lock-up box. for the tube. 



Telescopes with Zeiss Optical Outfits, on wood stand, with rack and pinion height-motion, 

 tube and accessories in box, stand-head in sail-cloth bag. 



Useful Auxiliaries: 



54.493. Fine Motion in azimuth and altitude 



51.494. Power 8 Finder 



54.495. Change Device 



54.496. Zenith Prism 



54.497. Herschel Solar Prism 



54.498. Ocular Spectroscope 



54.499. Ring Micrometer 



s. d. 

 9. 0.0 



1. 10. 



0. 15. 

 0. 15. 



10. 0. 



5. 0. 



1. 12. 



3. 10. 



5. 5. 



1. 16. 



1. 12. 



1. 0.0 



54,500. Dynameter after Eamsden, Figure, for direct determination of the power of a 

 telescope (M. P., 9 th Edn., II, 1, p. 872) 



Interference and Diffraction. 



52,045. Glass Balloon with Glycerine-soap Solution, after Eisenlohr, for showing Newton's 

 Eings in thin liquid films, Fig. 52,045, p. 284, for the Whirling Table 



154,501. Small Metal Frame for Soap Solution, Figure, for demonstrating the colours- of j 



thin plates (Graetz, ,,Das Licht und die Farben", Fig. 65; W. D. p. 445) j 0. 2. 



0. 7.0 



* Can be used with the Projection Apparatus. 



Cl. 1576, 824. 



