ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
587 
New Object-Finder.* — Herr R. Fuess has devised a new arrange- 
ment for re-finding interesting parts in microscopic objects, The 
apparatus, represented in natural size in fig. 92, is connected with the 
objective-changer shown in fig. 93. By its means a circle can be drawn 
with a diamond point on the cover-glass round any desired part of the 
object. 
To the piece Z, which by its upper conical part is clamped to the 
objective-holder, is screwed the socket H. In this fits the spring 
cylinder C which is pressed downwards by the spring S, and carries at 
Fig. 92. • Fig. 93. 
its lower end the sliding piece a, provided with the diamond point D 
and adjustable in position within a few millimetres. The eccentric 
position of the diamond point necessary for the production of circles 
with different radii is effected by the screw b and the counter-spring F. 
The little screw c prevents the falling out or rotation of the 
cylinder C. 
In the use of the apparatus, after the desired part of the object has 
been found by observation, the objective is removed and the apparatus 
clamped to the objective-changer in its place; the body-tube is then 
lowered until the diamond-point comes in contact with the cover-glass. 
The circular line can then be drawn in two ways, either : (1) by rotating 
the stage, or (2) by rotating the small apparatus in its socket H between 
the finger and thumb. 
The apparatus has the further advantage that by its means lines can 
be drawn at regular intervals in the case of Microscopes provided with a 
mechanical stage. 
Use of Coloured Light in Microscopy. f — Dr. A. M. Edwards con- 
siders that microscopists have not sufficiently appreciated the fact that 
the clearness with which an object can be seen depends much more upon 
the character than upon the intensity of the illumination. “ Colour is 
vastly more important than brilliancy.” The author gives an account 
of some experiments which he made on two objectives, 1 /5, as long ago 
as in 1865. With one of these, on Amphipleura , Cuba, only lines could 
* Neues Jahrb. f. Mineralogie, 1895, (1)2 pp., 2 figs, 
f English Mechanic, lxi. (1895) pp. 529-30. 
