432 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
by means of the rack and pinion g , a vertical motion by tbe rack and 
pinion c, and it can be rotated in a horizontal plane with the collar d. 
The two erecting oculars and o 2 are carried eccentrically, so that 
they can be accommodated to the distance between the eyes. The two 
objectives slide into grooves t. With the various oculars and objectives 
supplied with the instrument, amplifications of 6 • 5 to 48 are obtained. 
For use as a monocular, one of the tubes may be brought parallel to the 
rack by means of the turn-plate q. 
New Stand.* — Herr C. Reichert describes the new stand (No. VII 6) 
shown in fig. 33, which forms a cheap instrument for mineralogical and 
* Zeitschr. f. angew. Mikr., iii. (1897) pp. 74-5 (1 fig.). 
