188 



INo. 15 b,* 

 Alt. -Azimuth. 



Alt.-Azimuth, as in cut. Circles 8} inches diameter, micrometer-microscopes 

 reading to 5 seconds direct, and by estimation to single seconds. Telescope, 1.6 in. 

 aperture; focal length, 16 inches; power, 32 and 48. Telescope axis is of hardm.M! 

 steel and balanced by friction rollers. Reversing apparatus. Complete in one box. 



Price, as above, $92O.OO 

 This instrument without reversing apparatus. .... less, $100.00 



No. 15 C,* Alt.- Azimuth, "* /// rut nbove. Circles 10} inches diameter, mic- 

 rometer-microscopes reading to single seconds direct. Every single degree figured. 

 Telescope, If-inch aperture ; focal length, 20} inches ; power, 40 and 60. Telescope 

 axis is of hardened steel and balanced by friction rollers. Complete in two boxes. 

 m Price, as above, $13OO.OO 



* See Preface. 



