804 



SUMMARY OF OUEEENT RESEARCHES RELATING TO 



be turned into the centre of the field at pleasure. When the compounci 

 w^heel is lifted up as shown in fig. 103, the whole field of the Microscope 

 can be utilized for showing objects up to 1^ in, diameter. Thus the 

 compound wheel, 2^ in, diameter, yields just as large a field as can be 

 obtained by one of the ordinary- form when 5 in. diameter. 



When, as in using polarized light, it is not desired to be incommoded 

 with the wheel of diaphragms, the detachable plate carrying the com- 

 pound wheel can be instantly taken out of the stage, and when taken 

 out can be as quickly put in again. It should be noted that one stage 

 serves for all classes of objects, whether ordinary slides or polariscope 

 crystals shown with narrow-angle rays or the convergent system of 

 lenses. The tube for the polarizing prism is fitted for entire rotation, 

 and all the phenomena of polarized light can be demonstrated by the 



