48 



The B- 



just above the objective. It if 

 lii^ht is desired the analizer if 

 the abbe condenser is moved + 

 its place from the left. Wh 

 abbe condenser are moved 

 condenser taking the pi 

 These changes can be mauc 

 erable time that cannot be savcx 



acted that when polarized 



the right, at the same time 



and the polarizer swung into 



ght is desired the analizer and 



,eir original positions, the abbe 



isly occupied by the polarizer. 



y few seconds, thus saving consid- 



ith the ordinary microscopes, which 



are not similarly constructed. 



The present impracticable way of changing from plane to polarized 

 light with ordinary microscopes and the time consumed in the opera- 

 tion is well known to all microscopists. It is not necessary to have 

 an instrument as shown in this cut made to order. It is a simple 

 matter and not expensive for manufacturers of microscopes to fit any 

 microscope with an analizer in the draw-tube and a second substage 

 for the polarizer so that both can be brought into and thrown out of 

 'use as described above. 



This instrument has been in use in this laboratory for about six 

 months and has given satisfaction. 



