CH. VIII] 



MICRO-SPECTROSCOPE 



249 



FIG. 145. DIAGRAM OF A DIRECT-VISION MICRO-SPECTROSCOPE. 



1 The spectroscope is shown in position on the microscope, the tube of 

 the microscope being much shortened to save space. 



Stage, the stage of the microscope on which is a watch glass with sloping 

 sides. 



Objective The objective of the microscope. 



S S f S" Screws for clamping the apparatus and for changing the position 

 of parts. 



Slit The slit of the spectroscope between the ocular lenses in the position 

 of the ocular diaphragm. 



Hinge The hinge on which the prism can be turned off the ocular. 



Amid prism The direct-vision prism composed of a middle flint and two 

 crown-glass prisms. 



Red Yellou' Blue Arrangement of the colors as they emerge from the prism. 



Scale tube and Mirror The mirror to throw light into the scale tube and 

 project an image of the Angstrom scale into the field. 



2 Prism showing that with the eye close to the prism the colors seem re- 

 versed from the position actually occupied. 



3 Comp. prism The prism introduced under the slit and serving to reflect 

 up into the microscope a spectrum for comparison with that extending along 

 the axis of the microscope from below. C L Liquid in the tube whose spec- 

 trum is to be compared with that of the liquid in the watch glass on the stage 

 of the microscope. 



4 The slit mechanism and comparison prism (p). 



5 S' Set screws for changing the width and length of the slit. 



