578 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
MICROSCOPY. 
A. Instruments, Accessories, &c.* 
CD Stands. 
Hew Stand, with Polariser and Large Illuminator.f — Herr C. Leiss 
points out that, owing to the scarcity, and the consequently high price, 
Fig. 44. 
of Iceland spar, it is important to be 
able to replace the polarising Nicol 
prism by seme other arrangement ; 
since for convergent light it is neces- 
sary to have a Nicol with an open- 
ing large enough to correspond with 
that of the condensing system. It 
is common to see Microscopes in 
which the opening of the polariser 
is scarcely a third of that of the 
condenser. 
In the present stand (fig. 44), 
made by Fuess, the polariser consists 
of a bundle of thin glass plates P, as 
in the ordinary Norremberg polari- 
scope. The frame holding the plates 
can, with the mirror Sp, be moved 
about the axis g, and a mark indi- 
cates the proper polarising angle. 
The analyser is an ordinary small 
Nicol N. For ordinary light a 
mirror may be placed above the 
glass plates P. 
The illuminator is an Abbe’s 
triple condenser of N.A. 1*40; it 
can be lowered by the lever h, and 
turned out of position about the 
hinge h, thus affording an easy 
change from convergent to parallel 
light. The front lens of the con- 
denser has a diameter of 11—12 mm., 
and the lower lens one of 30 mm., 
those of the ordinary Fuess Micro- 
scopes being 6 mm. and 18 mm. re- 
spectively. This increase in the 
size of the condenser is to compen- 
sate for the loss of light by the 
glass plates P, and also to enable 
thick sections to be examined in con- 
vergent polarised light. The tube of 
* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- 
minating and other Apparatus; (4) Photomicrography; (5) Microscopical Optics 
and Manipulation ; (6) Miscellaneous. 
f Zeitschr. f. angew. Mikr., iii. (1897) pp. 138-41 (1 fig.). 
