THE USE OF THE MICROSCOPE. 5 
object becomes visible. Focus accurately by means of the fine 
adjustment. 
2. When using a high power, start with the objective the 
same distance from the object as before, and very gradually 
twist down the body until the object becomes dimly visible ; 
then complete the focussing by the fine adjustment. It will 
facilitate the process if, while twisting down the body with the 
a hand, you move about the object slightly with the left 
and, 
3. Take extreme care never to let the objective touch the 
object ; and never to touch or allow any dirt to get on the face 
of the objective. The face of an objective cannot be cleaned 
without doing harm to it. 
4, Should by any chance a drop of glycerine get on the face 
of the objective, stream it gently with water from a wash- 
bottle, and wipe it very carefully with a silk handkerchief or piece 
of chamois leather. Should Canada balsam be allowed to get 
on the objective, do not attempt to clean it yourself, but give 
it at once to the assistant. 
5. See that the body of the microscope slides smoothly in its 
tube. If it does not, remove it, and clean it by rubbing with 
a few drops of olive oil. 
6. Keep the eye you are not using open; a very little practice 
will enable you to do this, and it will save you much fatigue. 
Also get into the habit of using either eye. 
7. With a high power, use a small diaphragm: the amount 
of light will be somewhat diminished, but the clearness and 
definition of the object much increased. 
8. When examining an object, use your left hand to move 
the object about on the stage, and keep your right hand on the 
fine adjustment. 
9. If the object appears dim or dirty, find out where the 
fault lies, in this way :— 
While looking down the microscope, turn round the eyepiece 
with your right hand: if the dirt turns round too, remove and 
clean the eyepiece. If the fault is not in the eyepiece, move 
the slide about gently ; if the dirt moves with the slide remove 
the slide and clean it. If the dirt does not move with either 
the eyepiece or the slide the fault is almost certainly in the 
objective, which should be removed and examined ; if dirty, it must 
be cleaned very carefully with a piece of silk or chamois leather. 
