ASTRONOMICAL INSTRUMENTS. 

 Fig. 130. 



11') 



The Astronomical Telescope (Fig. 130, as above) consists 

 of an object and eye-glass fitted into a long brass tube. 

 The object-glass is placed at the end of the tube nearest 

 the object. The eye-glass is that which is nearest the 

 eye ; and when there are more lenses than one in the tube, 

 besides the object-glass, they are called eye-glasses also. 

 The tube is mounted on a brass stand having a joint and 

 swivel at the top, by which the telescope may be directed 

 to any position in the heavens. 



The short tube, C, adjusts in or out the body of the tele- 

 scope, by a rack and pinion, worked at A ; to the end of 

 which, the eye-tube, B, and the various powers are applied. 



The eye-tube, B, contains four glasses. To increase the 

 power, unscrew the eye-head of this tube, b, and take out 



