112 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
prism. The arm of the tube-support for connection with the prism 
broadens itself into a thick round plate p, in the middle of which the 
Fig. 1. 
Fig. 2. 
Fig. 3. 
prism i is screwed, while a supporting ring r projects dowtfwards over 
the prism-socket. The projecting piece from the socket consists of 
many parts. In the upper end of the socket three screw-holes (z ; fig. 1) 
are made; over these are placed three hol- 
low bolts a a a, which pass through the holes 
o of the plate p. Corresponding to the three 
holes in the socket are three holes in the 
plate s (figs. 1, 3), through which and the 
hollow bolts pass three screws, binding the 
parts into a single whole. 
To give the fingers a firmer grasp of the 
socket in lifting the Microscope, and to pro- 
tect the mechanism of the fine-adjustment 
from injury in the process, a projecting 
plate m is attached to the socket just beneath 
the tube-support. 
II. The adjustment by sliding tube. This method of adjustment, the 
author thinks, has received but “ stepmotherly ” treatment at the hands 
