530 



SUMMARY OF CUERENT RESEARCHES RELATING TO 



which acts as a substagc condenser. A bullseye on separate folding 

 tripod-stand is provided, and another much thicker bullseye is fitted 

 to the stage. The date of this old Microscope may approximately be 

 given as L790 to 1800. 



Fig. 49 shows the stand with the body set at an angle. To the ex- 

 treme left is a bullseye condenser on a stand having a tripod base ; 

 a stage bullseye condenser is also shown in the foreground to the 

 right ; it is excessively heavy, so heavy that its hinged joint fails to hold 



Fig. 51. 



it in any required position. A lieberkiihn with its holder are seen 

 in the foreground, and in the centre lies a spring stage for carrying 

 " sliders " containing objects mounted between discs of talc : attached 

 to this is a tube containing a substage condenser which slides in it for 

 focusing ; the tube is dropped through the opening in the stage-plate, 

 the spring-stage resting thereon. The use of the piece of apparatus 

 lying in the background is unknown, but it may have been intended to 

 hold a candle. 



