Joly — An Improved Polarizing Vertical Illuminator. 3 



aperture in the illuminator, so that the ray more nearly reaches 

 the glass at the polarizing angle, the polarization is still more 

 complete. 



As manufactured, the aperture is not placed so tha^t the 



polarizing angle can be actually attained. It should be located a 

 little above the axis of the reflector. The accompanying diagram 

 shows the proper angles for mirror and ray when it is desired to 

 obtain the ray as nearly unmixed with ordinary light as possible. 



