234 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



such movements. The illustration refers to the latter model, and is 

 considered by the makers to be self-explanatory. 



Micrometer Microscope.* — This instrument, mounted on a stand 

 (fig. 40), has a movable thread at the focus of the ocular for sub- 



Fig. 40. 



dividing the spaces on a graduated bar. The ocular field is about 9 mm. 

 Magnification from 30 to 40. 



Fig. 41. 



Dissecting Microscope.f— This instrument (fig. 41) has the arm 

 and dissecting stage, and is independent of the Microscope stand. The 

 objective, which has a rack-and-pinion adjustment, is composed of three 

 doubles. 



* List Phvs. and Mech. Instr. Soc. genevoise, 1907, p. 37 (1 fig.), 

 t Tom. oit., pp. 97-8. 



