187 



No. 15 a.* 

 Alt. -Azimuth. 



Alt.-Azimuthj as in cut. Graduations of 5/^ inch circles on solid silver, two 

 opposite micrometer-microscopes for each circle reading to 10", and by estimation 

 to 2". Botn circles can be shifted, so as to bring different parts of the graduation 

 under the micrometer-microscopes. The telescope islO inches long, has an aperture 

 of 1*4 inch and a power of 24 diameters. Telescope is provided with a level on top 

 and with 3 horizontal wires for leveling and for stadia measurements, and if desired 

 with 5 vertical wires for star observation. The telescope must be reversed in its 

 bearings by hand. Telescope axis is of hardened steel. The striding and microscope 

 levels read to 5" of arc. Two ordinary small levels attached to the instrument 

 serve to place it in an approximate horizontal position. Complete in box. 

 Price, as above, $58O.OO 



* See Preface. 



