354 F. J. CHESHIRE ON A SIMPLE FORM OF REFLECTING POLARISER. 



independent rotation. This is simply and efficiently effected by 

 sci-ewing it into the bottom of the draw-tube, in which position 

 it docs not limit the field of view, as is the case when mounted 

 in the eyepiece. The lipht incident upon the slip G should 

 preferably be made parallel with the usual bull's-eye. 



The single reflecting surface gives quite sufficient light for low 

 pcweis. If n oie is rfquiied for high powers, it can readily be 

 obtained by temporarily fixing with wax a large cover-glass on 

 the top of the slip G. 



The advantages of this simple form may be summarised as 

 follows: — It gi^es, practically, an unlimited field even for the 

 examination of stauro.scopic figures in the back of the objective. 

 It is readily fixed below and with the condenser. The position 

 of the plane of polarisation of the incident light is obvious. The 

 cost of the reflector is small as compared with that of a Nicol of 

 fair size. 



Journ. Quekett Microscopical Club, Scr. 2, Vol. VIII., No. 51, November 1902. 



