iris diaphragm lever: moving the lever to the left increases the light; moving the lever to the right decreases the light.
stage control "A": moves the mechanical stage holding the slide forward and backward.
stage control "B": moves the mechanical stage holding the slide left and right.
coarse focus: turning the knob away from you raises the stage; turning the knob towards you lowers the stage.
fine focus: turning the knob away from you raises the stage; turning the knob towards you lowers the stage.