120 



THE MICROSCOPE. 



extraneous light. The rays of light, after passing between 

 the knife-edges at K, are rendered parallel by means of 

 the lens at L. Then passing through the prism and con- 

 denser (c), they reach the object at o. The light is placed 

 at w, and if it be proposed to examine a liquid, it can be 

 placed in a small tube (T), closed at one end ; or a trans- 

 parent object may be placed on the stage in the usual 



Fig. 69. Sectional view of the Browning Spectroscope. 



manner. By the addition of a small telescope, instead of 

 a condenser, this contrivance can be applied to a micro- 

 scope in place of the eye-piece, and it can then be used for 

 the examination of opaque objects. 



The great objection to this form is its limited range, 

 and the constant shifting of parts it requires for finding 

 and focussing the object, and the awkward position of the 

 microscope, whether it be used under the stage or as an 

 eye-piece. 



Fig. 70. The Browning Hiiggin^ Micro-tpectroscope. 



The apparatus used by Mr. Huggins (fig. 70) was a star 



