ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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of 1/1000 in. to tlie metal block C. The diamond-carrier D, which is 
worked to and fro by hand, is kept in contact with the block C by 
springs. The working surfaces are formed by slips of plate-glass. The 
necessary clamps and springs are not represented in the figure. 
Covered Rectangular Motions for Stages.* — Dr. R. Brauns de- 
scribes an improvement on the usual rectangular stage-motions when used 
Fig. 38. 
p 7 
p xsl 
in connection with a graduated circle. The ordinary forms, in which the 
rectangular motions are above the circle, have the disadvantage of the 
graduations being often partly hidden and shadowed by the screws and 
slides ; the mechanism is further unprotected from dust and reagents. 
To the base-plate of the circle K (fig. 38) eight guides S are fixed, 
and between these the four prisms P move. To the last are fixed the 
* Zeitschr. f.^wiss. Mikr., xiv. (1897) pp. 11-3 (2 figs.). 
