The Operation of a Microscope 91 



The Operation of a Microscope 



Without a Sul)stage Condenser 



1. Place slide on stage and center the field to be examined over opening 

 in staoe. 



2. Turn lo^\ -power objective over specimen a short distance above it — 

 one-half inch will do. 



3. Adjust concave mirror, moving it back and forth, until light is as 

 unifomi as possible through the hole and onto the specimen. 



4. Raise the body tube by coarse adjustment until the specimen is in 

 focus. Check mirror, adjusting for better light. 



5. Higher powers may be swung into position and light adjusted if 

 necessary for greater magnification. 



With Siibstage Condenser and Lamp without Lenses 



1. Place slide on stage as above. Adjust objective, plane mirror and 

 body tube for focus as above. 



2. Remove ocular eyepiece and while looking down the tube open iris 

 diaphragm of the substage condenser until it coincides with the 

 margin of the back lens of the objective, just filling it with light, no 

 more. Focus the condenser up and down until the light is uniform 

 through the objective. 



3. Replace ocular eyepiece. Make similar adjtistments for all objectives. 



To adjust both parts of a binocular microscope, close the left eye and 

 focus with the fine adjustment tmtil the image is sharp for the right eye. 

 Leave the fine adjustment alone and focus for the left eye with the 

 focusing adjustment on the tube outside the ocular eyepiece. Between 

 the two eyepieces is an adjustment for changing the interpupillary dis- 

 tance between the eyes. Turn the adjustment slowly until the right and 

 left images blend and a single field is seen with both eyes. 



Critical Illumination {Kohler method) Using a Lamp with 

 Condensing Lenses and an Iris Diaphragm 



Lenses and an Iris Diaphragm 



1. Place a slide with fine-detailed specimen in position on microscope 

 stage. Center the condenser in relation to the stage aperture. 



