ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
127 
(5) Microscopical Optics and Manipulation. 
Collar- Adjustment of the Objective as affected by a Change of 
Eye-pieces.'* — -Dr. A. C. Stokes remarks on the general ignorance 
amongst amateur Microscopists of the use of the collar-adjustment in the 
change of eye-pieces, and regrets that so little stress is laid on this 
point in the standard Microscopical text-books. He gives the following 
table to show the range of alterations for various eye-pieces and objec- 
tives. The object examined was Pleurosigma angulatum on the Thum 
test-plate (styrax), with concave mirror 30° from axis. 
Eye-piece. 
Tulles 
4/10, 120°. 
Zeiss 
1/4, 144°. 
B & L. 
1/5, 130°. 
Gundlach 
1/5, 135°. 
Spencer 
1/5, 135°. 
Spencer 
1/5, 163°. 
Bulloch’s A, x 4J .. 
0 
1 
8 
S\ 
8 
P. & L.’s Comp. A, x 5 .. 
1 
17 
7 
8 
9 
8 
Griffith’s B, x 7*6.. 
111 
15 
6| 
8 
8 
U 
Zeiss’ Comp. 8 
10J 
16 
6 
ii 
7 1 
7 
Bulloch’s B, x 9 .. 
11 
13 
5 
7§ 
8 
7 
Bulloch’s C, X 12 .. .. 
15 
§i 
8 
8 
7i 
Tolies’ solid 1/2, x 20 .. 
ii 
13 
5 
7\ 
8 
7 
Zeiss’ Comp. 27 
101 
16 
6 
7\ 
7i 
7 
(6) Miscellaneous. 
Modern Microscopy .f — The second edition of this capital little 
manual has been enlarged by about 80 pages, the new matter being 
pretty equally distributed between “ Microscopy ” and “ Methods.” To 
the former is appended a short chapter on the influence of diffraction on 
the resolving power of objectives, by Dr. Johnstone Stoney, F.R.S., and 
to the latter a list of tissues and organs with the most suitable fluids 
for hardening, staining, and mounting them — a useful feature ; Mr. 
Hopewell Smith’s process of preparing teeth, and Mr. Rousselet’s 
method of preserving Rotifers. The favourable opinion expressed in 
this Journal on the first appearance of this work is fully justified by the 
present issue, and a beginner could not possess a more excellent and 
reliable guide. At the same time it may be as well to draw the author’s 
attention to one or two blemishes which should be removed in future 
editions. Steinheil is spelt Steinbeil , and Kellner Kelner in both, and 
if fig. 6 (“ un modele de luxe ”) is a model of anything but misapplied 
ingenuity, the makers would probably supply a newer cliche with a 
more modern form of fine-adjustment. 
Optics and Mechanics at the North German Commercial and In- 
dustrial Exhibition at Lubeck, 18954 — Dr. Max Ferenczy, in an 
article with the above heading, mentions amongst other exhibits those 
made by the firm of Zeiss. These included an exhibition of the methods 
in which the lenses for Microscopes and other optical instruments were 
prepared. The glass is first roughly shaped on a grindstone. On a 
* Micr. Bull., xi. (1894) pp. 18-9. 
t ‘Modern Microscopy,’ M. I. Cross and Martin Cole, London, 8vo, 182 pp. 
X Central-Ztg. f. Optik u. Meclianik, xvi. (1895) pp. 23S-9, 217-8, 257-9. 
