ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
603 
MICROSCOPY. 
a. Instruments, Accessories, &c.* 
The Microscope. Guide to Microscopical Technique.! — This 
small text-book of 140 pages contains a concise though fairly complete 
account of (1) the Microscope and its accessories ; (2) the use of the 
Microscope ; (3) preparations ; (4) graphical representation of prepara- 
tions. In the first section is a short history of the Microscope, followed 
by a description of its optical arrangements, from those of the very 
simplest to those of the most perfect instruments replete with the latest 
improvements. The second section treats of the use of the instrument, 
and contains a full account of the methods of adjustment and illumi- 
nation, the different sources of light, &c. The third section deals with 
the production of preparations of various materials. It also contains 
directions for the treatment of living objects, and for the cutting of 
sections, &c. The last chapter is devoted to the graphical representation 
of preparations. The various kinds of drawing apparatus are first 
described, and then the methods and apjdiances for photomicrography 
and projection are fully discussed. The whole book is plentifully illus- 
trated with plates and figures. 
(1.) Stands. 
Zentmayer’s American Continental Stand. — This stand has been 
designed to meet the wants of those workers who while preferring the 
compact Continental model are conscious of its inherent defects. It 
is substantially a combination of the upper half of American with the 
lower half of the best Continental stands. 
The stand is constructed entirely of brass ; the base is of horse-shoe 
form, filled with lead for extra weight, and gives perfect steadiness in 
every position. A stout pillar firmly supports the arm of the instrument 
on a trunnion-joint, which allows all inclinations from the perpendicular 
to the horizontal position. The coarse- and fine-adjustments are of the 
same style and construction as in the Centennial stand. The arm 
carrying the body is provided with two slides, the upper and longer one 
bearing the tube with rack-and-pinion movement, and sliding in the 
lower one, which is controlled by a lever of the second order, operated by 
a milled-headed micrometer screw in convenient position at the back of 
the instrument. At the bottom of the lower slide there is a shoulder 
against which the lever acts, and a spring above presses down against 
this shoulder, insuring its continuous contact with the lever during 
adjustments. All the mechanism is concealed within the arm, which is 
so hollowed as to secure both lightness and greater rigidity. This fine- 
adjustment is absolutely free from lateral motion, and exceedingly 
sensitive. Its construction prevents wear, and a revolving nose-piece 
and attached objectives can be easily carried without injury. It also 
acts as a safety appliance in case an objective is accidentally racked 
down against an object, for the spring yields quickly to upward pressure. 
The body-tube is 5^ in. long, with draw-tube extending full 10 in., thus 
* 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. 
t Sehweiger-Lerchenfeld, A.v., ‘Das Mikroskop. Leitfaden der mikroskopischen 
Technik nach dem heutigen Stande der theoretischen und practischen Erfahrungen.’ 
Wien, Pest, and Leipzig, 1892, 8vo, 192 figs. See Bot. C'entralbl., 1. (1892) pp. 261-2. 
