28 PUTTING OBJECTIVES AND OCULARS IN POSITION [Cn. I 



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 



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 an.d gently FJG ^ TRIpLE NosE . PIECE mTH THE THREE 

 force the ocular into posi- OBJECTIVES IN POSITION. 



