MICROSCOPICAL APPARATUS. 43 
has been found, it is very annoying to lose it in an 
attempt to move the slide a trifle one way or the 
other. 
The stand should be very steady, the movement 
by the coarse adjustment smooth and regular, and 
the fine adjustment as delicate as possible. 
It is of course essential that the body of the 
microscope be attached to the foot by a joint which 
permits of its being placed in a horizontal position. 
This joint must be firm, and there should be a sub- 
stantial arrangement for stopping or holding the 
body in an exactly horizontal position. 
An inner tube — draw-tube — is desirable, and 
this should be provided at its lower end with the 
Society’s screw, to hold an amplifier, and also for 
the purpose of carrying a low-power objective, 
such as a four or six inch lens; for the working 
distance upon most stands is not sufficient to per- 
mit the use of an objective of this focal length at 
the end of the outer tube. This arrangement 
also permits the operator to attach a Lieberkithn 
to the extremity of the outer tube, and a low- 
power objective to that of the inner tube, for the 
purpose of photographing objects by reflected 
light. 
The Lieberkithn and the objective may thus be 
focused separately, the former first, by the coarse 
adjustment, and the latter subsequently, by means 
of the draw-tube. The final focusing with the fine 
adjustment will not materially interfere with the 
position of the Lieberkiihn, which should be that 
which illuminates the object most effectually. 
