102 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the pillar x stands in the middle of the slit of the plate Z, when the 
whole instrument lies upon the Microscope-stage in such a way that the 
apertures of the stage and the plate P are concentric. 
The grooved head C is a rectangular block with a central smooth 
bore of such a size that it fits tightly on the rod x. Two of its opposite 
sides are provided with grooves in which the arms of the plate Z slide. 
The part of the rod x which projects above the head C, possesses a screw- 
thread for two screws SS, the upper for clamping the lower. These 
serve for the exact adjustment in height of the whole instrument above 
the Microscope-stage. 
Fig. ll. 
z 
The two-armed plate Z, which forms a long rectangle, consists of u 
single piece. On the length of its arms depends the extent of the 
lateral displacement of the object, which should amount to at least 3/4 in. 
After the introduction of the head C, the arms at the further side are 
closed by the cross-piece L which limits the displacement in this 
direction, while at the opposite side the plate is closed and is there also 
strengthened by a prismatic piece V, on which is a block B for the 
pressure spring D. The four-sided prism V fits between two projecting 
