CH. VII '] 



GLASS DEMONSTRATIONS 



195 



has a lock so that once the specimen is in the right position and the 

 instrument focused it may be passed around the class. For observa- 

 tion it is only necessary for each student to point the microscope 

 toward a window or a lamp. 



Fig. 150. Traveling microscope sset up for work (From Leilz' Catalog. ) 



