350 



Herbert C. Wilson 



The equatorial head and the bearings for the polar axis are 

 made in one casting. The coarse right ascension and declination 

 circles have large graduations and figures on the face, and are 

 easily read from the floor of the observatory. The fine circles 

 are graduated on sterling silver, and are read by verniers and 

 reading glasses, illumined by small incandescent electric lamps. 



The driving clock is of the same pattern as those provided with 

 the larger telescopes above mentioned. It is governed by a 



Fig. 3. Edwin Brant Frost, Director of the Yerkes Observatory. The address 

 delivered by Professor Frost at the Dedication of the Swasey Observatory is 

 printed in this number of the Bulletin. 



double conical pendulum mounted isochronously, making three 

 revolutions per second, and its movement is connected with the 

 polar axis by means of a continuous worm gear having 360 teeth. 

 The telescope tube is of sheet steel, very light and rigid. It 

 is provided with right ascension and declination clamps and slow 

 motions, which are governed by handles and knobs within easy 

 reach of the observer. On the north side of the column is placed 



