7 
Exercise 2. Examination of Objects Under tlie Microscope 
MATERIALS: 
3 Plain glass slides 
2 Cover glasses 
Clean sand 
Copper chloride crystals 
Cotton fibers 
Wool fibers 
1. On a clean slide place near the center a few grains of sand and a few copper 
chloride crystals. 
2. Adjust the microscope. 
3. Place the slide on the stage of the microscope with the objects to be 
examined over the opening. See that the clamps hold the slide securely. 
4. Swing the low power (16 m. m.) objective into position and lower the 
tube until the tip of the objective is within 4 m. m. of the object on the 
slide. 
5. While looking into the microscope, slowly raise the tube by turning the 
coarse adjustment toward you until the objects come into view. It is well to 
move the slide a very little while focusing in order that the objects may more 
easily be detected. Do not mistake shadows of your eyelashes, or dust and 
lint particles on the lenses of the eyepiece for the objects to be examined. 
Turn the eyepiece to see if any such particles move. If so, they are on the 
eyepiece. If the lenses are very dirty, clean them with lens paper. If this 
does not remove the dirt, ask the instructor to clean them for you. 
6. Try changing the amount of light by opening and closing the diaphragm. 
Draw the objects as seen with the 16 m.m. objective, remembering the regula¬ 
tions for drawings. (See page 2, paragraph 10.) 
7. Place a large drop of water on a slide. In the water place a few wool 
fibers. Clean a cover glass. Hold it inclined so that the lower edge touches 
the slide and the edge of the drop. Lower it carefully in order that the space 
beneath the cover glass will be completely filled with water and not with a 
mixture of water and air. Remove excess of water with a blotter by blotting 
gently as when blotting ink. Examine the fibers with the 16 m.m. objective. 
Draw and describe them as seen with this objective. 
8. Examine the fibers with the 4 m. m. objective. Draw them as seen with 
this objective. 
9. Examine some cotton fibers in the same manner. Draw them as seen 
with the 4 m. m. objective. 
10. Examine some threads, warp and woof, from your suit. Is it all wool? 
11 . 
(a) How do the numbers of the objectives correspond to their 
distances from the objects when in focus? 
( b ) With what intensity of light can the details of the wool be 
most easily distinguished? 
(c) What is the structure of the wool fiber as shown by its appear¬ 
ance under the microscope? 
( d ) What is the structure of the cotton fiber as shown by its 
appearance under the microscope? 
