THE MICROSCOPE. 
90°, the pin G being withdrawn, so as to leave the bar deg 
with the stage and its appendages free to turn on the joint E with 
the arm E c. The body e and the bar deg will then be brought 
Fig. 39. 
into the horizontal position. The stage will then be vertical, and 
the object will be held in its position by the springs. 
The illumination of the object may be produced either by the 
reflector or lens in the manner already described; or, if they are 
removed from the bar deg, the stage may be presented directly 
to the light of the sun, the clouds, or a candle or lamp. 
In some cases, however, when it is necessary to obtain a more 
intense illumination, an apparatus represented at s s' is employed, 
consisting of two convex lenses placed in the ends of a conical 
tube which slides upon the bar, by means of a square piece at the 
end of the arm t. 
76 
