to that just described, but is so arranged as to throw
the image vertically downwards behind the microscope
when the latter is inclined at an angle of 45 degrees.
In this case also the picture reflected is clear and
sharp, devoid of all disturbing secondary images. As the
image is reflected vertically downwards upon the table,
no special drawing stand is necessary as there is no
distortion of the picture. The intensity of the light
may be modified by smoked glass plates mounted in two
moveable metal arms =10.--=
For a description of these drawing eye-pieces and of the
principles involved in their construction reference may
be had to the Zeitschrift für wissenschaftliche
Mikroskopie, XII, 1895.
[Illustration: Abbe's Drawing Apparatus.]
94. In =Abbe's Drawing Apparatus= the drawing field is
reflected by a mirror at the side of the instrument and
by a prism which fits over the eye-piece of the
microscope. The prism is supported on a vertical hinge
so that it may be readily turned out of the axis of the
microscope without disconnecting the whole apparatus
from the stand. It is shown turned to the side in the
figure. A cylindrical cap accompanies the apparatus
which fits over the prism holder and has six lateral
windows in which are smoked glasses of various
intensity, serving to regulate the lightness of the
reflected drawing field =12.--=
[Illustration: Drawing Board No. 95. Drawing Board after Giesenhagen.]
The =Drawing boards= serve two purposes. They afford a
smooth plane surface for the drawing paper and they are
so arranged that they may be inclined at such an angle
as to receive the rays of the reflected image at right
angle to their surface, thus doing away with any
distortion of the image on the paper.
95. This =drawing board= is especially adapted for use
with drawing eye-piece No. 92. When in the position
indicated in the figure its drawing surface forms an
angle of 12° to the horizontal =2.--=
96. In =Giesenhagen's drawing board= the drawing surface
may be adjusted at various angles and may be raised and
lowered =4.--=
For drawing eye-piece No. 93 and the Abbe drawing
apparatus the surface of the drawing board should be
horizontal.
[Illustration: Drawing apparatus after v. Tubeuf.]
97. The =drawing apparatus= after v. Tubeuf serves for
drawing objects from nature. By means of a prism mounted
in a metal box, the object is reflected into the eye in
such a manner that its image appears erected on the
drawing surface. This is quite an advantage when drawing
from nature but is unimportant when using a drawing
apparatus on the microscope. Two smoked glasses mounted
in moveable metal arms serve to moderate the intensity
of the light. On the side of the prism nearest the eye
is a small wheel diaphragm attached to regulate the size
of the opening. The apparatus is mounted on a heavy
nickel-plated stand with vertical and lateral
adjustments controlled by thumb-screws =12.--=
=Mechanical Stages.=
[Illustration: Mechanical stage No. 98.]
98. =Mechanical stage= adapted to Stands I, Ia and Ib.
The stage is readily attached to the microscope by means
of a small screw, _C_, which screws into a thread in the
microscope just behind its stage, and binds the
mechanical stage firmly in position and always in the
same position. It may be again removed by simply
unscrewing this set screw.
The movements of the stage are at right angles to one
another, are accomplished by carefully constructed rack
and pinion adjustments and the exact position of each
adjustment is indicated by vernier scales. The extent of
the lateral movement is 50 mm; that of the other 30 mm.
This stage permits the careful and systematic
examination of large specimens and its construction is
so perfect that by means of the vernier scales the most
minute objects may be readily replaced in the field of
vision, even after removal and readjustment of the
stage, provided only that their location when in the
field of vision as indicated by the scales had been
noted =28.--=
99. =Large mechanical stage= for stand, _A_, adapted for
slides 50×100 mm; both movements by rack and pinion
adjustments =32.--=
[Illustration: Mechanical stage No. 100.]
100. =Mechanical Stage No. 100.= When a mechanical stage
is ordered subsequently to a microscope outfit and under
such circumstances that its correct adjustment to the
stand by a skillful mechanic is impossible we advise the
purchase of this more readily adjusted mechanical stage,
which may readily be attached to Stands I, Ia, Ib, IIa
and IIb by means of a thumb-screw. It is as carefully
constructed as Mechanical Stage No. 98 and serves the
same purpose in every particular =28.--=
100a. =New Mechanical stage=, simplified form =20.--=
[Illustration: Mechanical stage No. 100a.]
101. =Warm stage= after Schultze. This consists of a
metal stage to which long lateral arms are attached,
through which the heat from one or more small lamps is
conducted to the central part of the stage and the
object. The apparatus is also provided with a condenser,
which affords illumination sufficient for the use of
high power objectives, and with a thermometer indicating
the exact temperature of the centre of the stage, which
may be carried as high as 100° C. =12.--=
[Illustration: Schultze's Warm Stage No. 101.]
102. =Warm stage= after Pfeiffer. It consists of a glass
chamber through which warm water may be made to flow. A
small cell is ground in its surface thus permitting its
use as a moist chamber =6.--=
103. =Warm stage= after Stricker. This stage consists of
a metal chamber, through which warm water is made to
flow when in use, and is provided also with a condenser
and thermometer. It may be screwed firmly to any of the
square microscope stages =14.--=
[Illustration: Stricker's Warm stage No. 103.]
104. =Warm stage= after Errera, permitting rapid changes
from low to high temperature and vice-versa.
It includes 2 vessels for cold and hot water, mounted on
tripods, with rubber-tubing etc. =24.--=
=Photo-micrographic Apparatus.=
[Illustration: Photo-micrographic Apparatus No. 105.]
The method of employing this apparatus and the general technique of
photo-micrography are treated of in a separate pamphlet containing also
four photo-micrographs taken with this apparatus.
This little work is furnished with each apparatus.
105. =The Photo-micrographic Apparatus= consists of a
heavy iron foot supporting a stout column in which
another iron support moves vertically. This latter holds
the camera and may be firmly fixed at any height by
means of a thumb-screw. This permits the accurate
adjustment of the camera to microscope stands of various
sizes. The length of the camera is also adjustable by
means of a thumb-screw sliding in the upright support.
Regulation of the field of the camera is accomplished by
a revolving disc diaphragm with openings of five
different sizes situated in the neck of the camera. Two
simple plate-holders for plates 9×12 and 13×18 cm are
supplied with each camera, as are also a ground glass
plate and clear glass plate in the frame of the camera
serve to catch the picture in the plane of the
photographic plate, and a simple lens aids in obtaining
a correct focus of the image. A white glass plate,
mounted on a stand is of use in diffusing direct
sunlight so as to make it available for photographic
purposes, and three discs of yellow, blue and green
glass are provided which may be inserted over the iris-
diaphragm of the condenser when colored light is
required.
It is of great advantage to interpose an illuminating
lens between the source of light and the mirror, thereby
condensing the light-rays, giving a uniform illumination
and preventing the heating up of the entire stand, which
is a disturbing factor in retaining the focus. The
illuminating lens also serves to lessen the time of
exposure.
This photo-micrographic apparatus is also available when
it is desired to photograph gross specimens as, for
example, embryos, insects, etc., by reflected light, as
is represented in the figure on p. 86. The photographic
objective of 64 mm focal distance, is best adapted to
this purpose. It fits in a collar in the neck of the
camera and yields a magnified image of about 3
diameters. The object is brought into proper focus by
means of a small stand, the table of which may be raised
or lowered as required.
Price of the apparatus without microscope stand =40.--=
106. =Small stand for supporting specimens= to be
photographed by reflected light as mentioned above =4.75=
107. =Welsbach lamp= with reflector =6.--=
108. =Illuminating lens= of 100 mm diam. on stand =12.--=
109. =Photo-micrographic apparatus=, for use in
horizontal and vertical position. It is in construction
similar to the foregoing, but is provided with joint for
inclination and clamping lever, and can be used at any
angle.
Large size bellows and plateholder, for plates up to
24×24 cm. Moveable platform with three leveling screws
and clamping-bar for holding stand. Price of the
apparatus, with 2 simple plate-holders, ground and plain
glass plate, etc., without microscope stand =60.--=
[Illustration: Photo-micrographic Apparatus No. 109.]
=Edinger's Projection Apparatus.=
[Illustration: Edinger's Projection Apparatus with Nieser's Photographic
Camera.]
110. =Edinger's Projection Apparatus=--For projecting
and drawing large objects slightly magnified. (Cf.
Zeitschrift für wissensch. Mikroskopie. VIII. 1891.)
A polished wooden base, in which a lime wood drawing
tablet is inlaid, supports a wooden stand which in turn
holds a horizontal metal tube in which are a collecting
lens and a reflecting mirror. The upright also carries,
two arms, by rack and pinion adjustment, the one
supporting the object stage, the other regulating the
length of the camera. On the other side of the upright
is a support for a lamp. The rays of this lamp are
converged by the collecting lens upon the mirror, are
reflected downward to the object and through the
objective to the drawing board below. The various
adjustments permit considerable variation of
magnification with the same objective.
Price, including lamp =18.--=
For photographic purposes this same apparatus may be had
with Nieser's photographic camera, plate holders,
focussing plate etc.
111. =Edinger's Projection Apparatus with Camera= for
plates 9×12 cm and 13×18 cm =38.--=
112. =Larger Projection Apparatus with Camera= for
plates 9×12, 13×18, 18×24 and 24×30 cm =56.--=
The following Objectives of 24, 35, 42 and 64 mm focal
distance respectively may be used in connection with
this apparatus for photographic purposes.
113. } { of 24 mm focal distance =18.--=
114. } =Photographic Objectives { " 35 " " " =18.--=
115. } with Iris diaphragms= { " 42 " " " =18.--=
116. } { " 64 " " " =20.--=
The following table shows the size of the preparation
which may be resolved by each one of these objectives
and the magnification with the smaller and with the
larger Edinger Projection Apparatus.
-------------+----------------+--------------------------------------
| Size of the | Magnification
Objective | Preparation | |
Focal length | Maximum | Smaller Apparatus | Larger Apparatus
-------------+----------------+--------------------+-----------------
24 mm | 8 mm | 7-15 diam. | 13-25 diam.
35 mm | 15 mm | 5-12 diam. | 10-20 diam.
42 mm | 20 mm | 3-9 diam. | 6-13 diam.
64 mm | 35 mm | 2-4 diam. | 3-8 diam.
-------------+----------------+--------------------+-----------------
The time required for exposure in photographing with this
apparatus is from 5 to 20 seconds according to the magnification
and character of the specimen.
The following figure shows a further use for the Objective
of 64 mm focal distance in connection with the photomicrographic
apparatus (page 82).
[Illustration: Photo-micrographic apparatus No. 105 with small stand No. 106.]
=Large Projection Apparatus.=
In this projection apparatus an electric projection lamp is made use of,
the lamp being available for electric currents of 20 Ampères and about
48 Volts. To regulate the current a rheostat is necessary. When using
constant current the carbons should stand at an angle in order to
utilize to best advantage the stronger light of the positive (upper)
carbon. For spectroscopic projections the carbons of the lamp have to be
in vertical position.
Connected with the lamp is a triple condenser of 150 mm aperture. The
latter should be protected from the heat-rays by a large mica-plate
which is furnished with the apparatus.
Various devices permit very accurate adjustment of the lamp and
condenser. For example, two thumb-screws control the position of the
carbons of the lamp so that the luminous point may be readily brought
into the exact optical axis of the condenser. Again, the two inner
lenses of the condenser are moveable and are controlled by two knobs
conveniently situated as shown in the illustration.
By this adjustment of the lenses of the condenser it is possible to do
away with disturbing chromatic aberration. The rays of light leave the
condenser in moderate convergence.
For direct projection from the preparation the apparatus consists of the
optical bench upon which are mounted the various accessories in proper
succession (Fig. p. 88):
1. A large cooling cell, which is to be filled with water or alum
solution.
2. The bellows with tube. This is connected with the cooling cell by
means of a metal ring which slips over the end of the cell and is held
in place by a screw. The metal ring is attached to one end of the
bellows, while the other end carries a large tube.
3. The microscope condensers and diaphragm holder. A larger tube fits
over the tube of the bellows and carries on a revolving arm the cylinder
diaphragm and the two condensers. For low power objectives Nos. 1-3, the
cylinder diaphragm and the condenser of longer focus have to be used.
The latter at the same time serves as the objective for lantern slide
projection.
The other condenser is especially needed when high powers are employed
(Objectives 4 to 6). A small rack and pinion arrangement serves for the
adjustment of condenser and diaphragm.
4. The object stage and small cooler. The stage has connected with it a
second cooling cell on which the preparation rests. This arrangement
permits prolonged use of the condenser and the greatest intensity of
light without burning the most delicate specimens. The adjustment of the
object is accomplished by means of an arrangement which permits any
particular point to be brought accurately into the field.
[Illustration]
5. The objective carrier is provided with a nose-piece for three
objectives, with a broad projection tube, having an Iris diaphragm for
the purpose of narrowing the aperture, and with a narrow tube which
screws into the broad one, in case it is desired to use oculars in
making the projection. The adjustments of the objectives are
accomplished by rack and pinion and by micrometer screw.
In order to change readily from microscopic to lantern-slide projection,
the parts 4 and 5 have been provided with hinges, by means of which they
can be thrown to one side after loosening a lever (see illustration
below).
6. Wooden cover with cloth curtain which fits over the diaphragm
carrier, the stage and the objectives, to shut off any light which may
escape at the sides.
For the projection of large preparations of from 8-35 mm diameter our
photographic objectives of 24, 35, 42 and 64 mm focal distance are best
adapted (p. 86). In connection with these low powers the large tube only
should be used.
[Illustration]
With this projection apparatus the powers of microscope objectives till
number 6 may be well employed.
The picture, even when the highest powers are made use of, and the
screen is at a distance of twelve feet from the apparatus, is of
sufficient clearness and brightness to be available for demonstration to
a large audience.
For the projection of lantern slides or of large section of tissue
following parts of the apparatus are required: Lamp, condenser, cooler
and bellows are the same as in the above described apparatus.
The stage and objective carrier are swung to one side.
The special-projection lens of 300 mm focal distance is to be used.
A slide carrier slips into the frame of the bellows, which is
sufficiently large to accommodate lantern slides 9×10 and 9×12 cm in
size. The slide carrier has a stop at both ends which facilitates its
adjustment in the axis of the instrument, and is arranged for the
simultaneous reception of two slides, so that while one is being
projected it may be charged with a second which may then without delay
be pushed into the optical axis as the first is removed. In this way
series of pictures may be thrown on the screen without interruption.
When so arranged the projection can be made upon a screen 30 feet from
the apparatus, over the heads of an audience.
Prices:
117. =Projection-lamp= for current of 20 Ampères, with
centering arrangement =92.--=
=Fixed rheostat= =30.--=
(The same, adjustable =$45.--=.)
Lamp and rheostat are furnished at factory prices. In
ordering it is well to state the strength of the
available electric current, also whether it is constant
or alternating.
=Outfit for projection of lantern slides:=
Metal-base with optical bench, triple collecting lens
(adjustable) of 150 mm aperture; large cooling cell;
slide carrier with bellows; triple revolving arm, with
rack and pinion adjustment =108.--=
Projection objective of 300 mm focal length =20.--=
(A second objective of same focal length may be slipped
over the former, the two combined represent an objective
of 150 mm focus. Additional price =$20.--=.)
=Outfit for microscopical projections:=
Cylinder-diaphragm and condenser; objectstage and small
cooler with moveable slide-holder. Objective carrier
with triple nose-piece: rack and pinion adjustment and
micrometer-screw. Broad tube with Iris-diaphragm into
which the smaller draw-tube fits. Two projection eye-
pieces.
Object-stage and objective carrier are provided with
hinges. Wooden cover with cloth curtain =84.--=
Transport =250.--=
--------
Complete outfit =334.--=
118. =Megascope=, apparatus for the projection of opaque
objects; special offers will be made on application.
119. =Attachment for spectroscopic examinations=, to be
used on the optical bench and in connection with the
lamp of the projection apparatus No. 117. Slit
mechanism, large triple prism, object-stage =80.--=
120. =Large projection apparatus=, of special design
with latest improvements, for lantern slides size 13×18
cm, for micro-projection, and megascope attachment.
Special offers for this apparatus will be made on
application.
(In ordering it is necessary to state the voltage of
the available electric current, also whether it is
direct or alternating.)
121. =Trichinoscope.= Simple electric lamp (hand feed)
of 20 Ampère, mounted on adjustable stand, encased in
Russian iron box, double collecting lens (adjustable) of
120 mm Aperture, with condensing lens.
Mechanical stage for glass compressors, with movements
at right angles to each other, cooling cell for the
preparation with a continual flow of cold water.
Objective carrier with micrometer screw, wide tube with
Iris diaphragm =120.--=
Projection objective of 35 mm focus, aperture f:3,5,
with Iris diaphragm =18.--=
--------
=138.--=
[Illustration: Trichinoscope No. 121.]
=Microtomes.=
[Illustration: Large Sliding-Microtome.]
Our larger microtomes are heavy and all their adjustments are of the
most accurate construction, the result being that they are very steady
when in use and permit the cutting of very thin and uniform sections.
They are to be had in three different sizes. The larger two are slightly
different in construction from the third. The two former microtomes are
provided with an automatic feed attachement. A heavy knife-carrier
slides smoothly and rapidly on a horizontal track and is so arranged
that it may be manipulated by the hand of the operator alone or by a
wheel and chain device, which tends to assure a perfectly uniform stroke
of the knife.
The objectclamp is raised vertically by a micrometer screw. This motion
is accomplished by turning a large disc having teeth cut into its
periphery and a turn of one tooth being equal to an elevation of 0.0025
mm.
The automatic feed is arranged as follows: With each return of the
knife-carrier to the end of its track pressure is made upon an
adjustable lever which regulates the motion of the micrometer wheel.
This device may be so adjusted as to move the micrometer disc any number
of teeth from one to ten with each sweep of the knife.
Three different forms of clamps may be had for these microtomes, and
freezing apparatus as well as paraffin tables can also be fitted.
The Fixed clamp, No. 128, represented in the figure of the large sliding
microtome, serves to clamp the specimen in position and does not allow
any further adjustment.
The Ball and Socket clamp permits the adjustments of the specimen after
it is held in the clamp by means of a ball and socket joint--see figure
of No. 129--a set-screw then holds it firmly in position.
The Naples clamp permits the accurate adjustment of the specimen at any
level, the clamp being supported on two horizontal axes at right angles
to each other, the one controlled by rack and pinion, the other by
endless screw.
The knife-carrier is arranged to hold the Thoma form knives, which are
fastened by means of a wing-screw. Other knives require a special
holder, such as No. 139.
122. =The Large Sliding Microtome= has a track 42 cm
long. Its price with automatic feed attachement, wheel
and chain arrangement for the knife carrier, and fixed
clamp, without knife =62.--=
123. =The same=, with knife holder for Jung microtome
knives =66.--=
124. =The same=, but without the wheel and chain
arrangement for the knife carrier =50.--=
125. =Medium size Sliding Microtome=--Track 32 cm long;
automatic feed attachement; wheel and chain motion of
knife carrier and fixed specimen clamp--without knife =56.--=
126. =The same=, with knife holder for Jung microtome
knives =60.--=
127. =The same=, but without wheel and chain motion =44.--=
128. =Fixed Specimen Clamp= =4.--=
129. =Ball and Socket Clamp= =6.--=
130. =Naples Clamp= =12.--=
[Illustration: Ball and Socket Clamp No. 129. Naples Clamp No. 130.]
131. =The Support-Microtome= has a track 19 cm long. The
knife-carrier slides on a double flanged support and is
moved by means of a large knob. The motion is smooth and
quick. The specimen is held in a clamp supported on two
adjustable axes at right angles to each other, thus
permitting its adjustment in any position. The specimen
carrier is moved vertically by means of a micrometer
screw to which a large disc is attached. This disc is
graduated, each degree representing a motion of the
specimen carrier of 0,005 mm. The price of this
microtome with knifeholder No. 139, without box or knife
is =34.--=
[Illustration: Support-Microtome No. 131.]
131a. =Small Sliding Microtome=, length of bed 21 cm,
heavy knife-carrier, object clamp for specimen 25 mm
diam., micrometer screw with disc graduated into 100
degrees, each division representing a motion of 0,005
mm. Price including knifeholder No. 139, without knife =24.--=
[Illustration: Small Sliding Microtome No. 131a.]
=Microtome knives.=
(Made by W. Walb.)
=A. Thoma's Model=, plano-concave, with handle adapted
for clamping immediately to the knife carrier of the
microtome, in box.
[Illustration]
132. Length of cutting edge 36 cm =26.50=
133. " " " " 24 cm =13.25=
134. " " " " 16 cm =8.50=
135. " " " " 12 cm =5.50=
=B. Jung's Model=--plano-concave--requires knife-holder
No. 139--in box.
[Illustration]
136. Length of cutting edge 24 cm =11.25=
137. " " " " 17 cm =6.--=
138. " " " " 12 cm =4.75=
139. =Knife-holder= designed for Jung's Microtome knife =4.--=
140. =Freezing apparatus= for Microtomes =8.--=
[Illustration: Freezing apparatus No. 140.]