366 



WELLS'S NATURAL PHILOSOPHY. 



Fig. 302. 



reflected by a small 

 mirror, C D, and forma 

 an erect image at n m, 

 wiiich is magnified hy 

 the lens, E, when ob- 

 served hy the eye. 



Fig. 303. 



Another form of 

 the reflecting tele- 

 scope, called the 

 Newtonian, is rep- 

 resented in Fig. 303. 

 It consists of a largo 

 concave speculum, 

 A B, set in one end 



of a tube, and a small plane mirror, C D, placed obliquely to the axis of the 

 tube. The image of a distant object formed by tlie spoculum, A B is reflect- 

 ed by the mirror, C D, to a point, m' n', on the side of the tube, and is there 

 viewed through an eye-glass, E. 



Fig. 304. Large reflecting telescopes, 



at the present da\', are so con- 

 structed as to dispense with 

 the small mirror. This is ac- 

 complished by slightly inclin- 

 ing the large speculum, so as 

 to throw the image on on» 

 side where it is viewed by an eye-glass, as is represented in Fig. 304 



Fig. 305. 



