28 PUTTING OBJECTIVES AND OCULARS IN POSITION [Ch. I 



Fig. 26. Double Nose-piece with the 

 Objectives in Place. 



Experiments with the Compound Microscope 

 § 44. Putting an objective in position and removing it. — Elevate 



the tube of the microscope by means of the coarse adjustment (fig. 



25) so that there may be 

 plenty of room between 

 its front or lower end and 

 the stage. Grasp the ob- 

 jective lightly near its 

 lower end with two fingers 

 of the left hand, and hold 

 it against the nut at the 

 lower end of the tube or 

 the revolving nose-piece 

 (fig. 26-28). With two 

 fingers of the right hand 

 take hold of the milled 

 ring near the back or up- 

 per end of the objective and screw it into the tube of the microscope 



or nose-piece. Reverse this operation for removing the objective. 



By following this method 



the danger of dropping the 



objective will be avoided. 

 § 45. Putting an ocular 



in position and removing 



it. — Elevate the body of 



the microscope with the 



coarse adjustment so that 



the objective will be 2 cm. 



or more from the object, 



grasp the ocular by the 



milled ring next the eye- 

 lens (fig. 25) and the coarse 



adjustment or the tube of 



the microscope and gently FlG 



force the ocular into posi- 



27. 



Triple Nose-piece with the Three 

 Objectives in Position. 



