ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
435 
facilitate the lateral movement of 62 mm., a small crank a has been 
inserted in the right-hand milled head, and a notch in the vertical 
Fig. 99. 
column allows the full extent in the other direction. The inventor^has 
found the stage of great assistance, especially when he wished to draw 
by the camera lucida the developments in a 
series of sections. Fig. 100. 
Adaptation of Greenough’s Binocular to 
the Ordinary Microscope.* — Prof. Eternod 
criticises Greenough’s binocular as a valuable 
piece of apparatus, but bulky, embarrassing, 
and costly. Messrs. Zeiss have however sup- 
plied him with the binocular tube and lenses, 
which he has succeeded in fitting to an ordi- 
nary stage, and thus reducing the binocular to 
the rank of a simple accessory. A rackwork 
(fig. 101, b), prepared by his assistant, Mr. 
Jaccard, provided the necessary attachment, and 
it was found very convenient to be able to use 
the instrument in a slanting position. More- 
over Abbe’s illuminating apparatus exactly 
suited it, and the inspection of objects in series, 
such as embryo sections, gained a precision un- 
attainable with a single tube. 
Reichert’s New Coarse Adjustment. — The 
principle is the rack-and-pinion (fig. 102), 
which is made of gun-metal specially hardened, 
and a very important feature is the springing 
with adjusting screws, a , ?>, c, for tightening up. 
The tube-mount is regulated by a , and the 
pinion by b, c ; thus the unavoidable wear and 
tear can be compensated for. 
* Zeiteelir. f. wiss. Mihr., xv. (1899) pp. 419-21. 
