5 E 



2070 Meridian Instruments (Mounting and Description). 



Transit Circle, Visual and Pliotograpbic. 

 Zenith Telescope, Visual and Photographic. 

 2080 Extra-Meridian Instruments for Absolute Position. 



Altazimuth. 

 Vertical Cii'cle. 

 Almucantar. 

 Various. 

 2100 Auxiliary Instruments 



Clocks, Chronoriieters, Watches, Chronographs. 



{See also B 0150). 

 Levels. 

 2120 Eyepieces and Accessories. 



Eyepieces, Illumination, Screens, Solar Eye- 

 pieces, etc. 

 Eidarg-ing- Lenses, Correcting Lenses, etc. 

 Photog-raphic Plate Holders, Exposing Shutters, 

 etc. 

 2140 Micrometers. 



For Visual Telescopes. 



For Measuring Photographs, Solar and Stellar. 

 2200 Spectroscopic Apparatus. 



2210 Objective Pri^^m. 



Objective Grating. 

 2220 Solar Spectroscopes and Spectrographs with Slits. 



Eclipse Spectroscopies and Spectrographs. 

 Stell.Hr Spectroscopes and Spectrographs. 

 Spectroscopes and Spectrographs for Study of 



Nebulje. 

 Ocular Spectroscopes. 

 2240 Prism Combinations with Deviation. 



Prism Combinations with Direct Visicm. 

 Slit. 

 2250 Auxiliary Apparatus. 



Production of Comparison Spectra. 

 Correcting Lens tor Spectroscopic Oliscr- 

 vations. 

 2200 Micrometer for Visual Observations. 



Micrometer for Measuring Photographic 



Spectra. 

 Miscellaneous. 

 2270 Spectroheliograph and Apparatus for Muno- 



chromatic Images. 

 2280 Theory, Adjustment. 



CoinparisDu of ElHciency of Instruments. 

 2300 Polarization Apparatus. 



2400 Photometry, (ieneral. 



Visual. 



Piiotographii'. 

 Spectropliotometry. 

 2500 Kadiometry (Holometry). 



2600 Miscellaneous. 



