244 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



provided, so that an assistant may equip it with slides and exchange it 

 for the first disk at the proper time. It is recommended that the 

 ocular be removed, and projection effected by a projection-objective alone. 



6 



Koristka's Apparatus for Drawing with Weak Magnification.* — 

 This apparatus, shown in fig. 50, consists of three distinct parts : 



* F. Koristka, Milan, Catalogue xiii. (1908) Microscopi ed Accessori, p. 61. 



