OF 3IICEOSCOPIC OBJECTS. 23 



tubes into that which embraces the glass ring and the end 

 of the microscope tube one for the entrance, tbe other for 

 the exit of the gas. This is a simpler and less costly plan 

 than that devised by Strieker. Prey observes that it is 

 most advantageous to use immersion lenses and the moist 

 chamber with the hot stage. 



