Part 2

1. =The foot and upright support= are solid and are of such weight and shape as to permit inclination of the body of the microscope to a horizontal position. The foot is horse-shoe shaped and is made to touch the table at three points, thus insuring stability even on a surface which is not entirely level. Inclination of the body of the microscope is permitted by a joint in the upright, which joint may be fastened in the larger stands by a set-screw operated by a lever. Stands Ia and IIb are also made with the English foot. Abundant space is left under the stage for the various attachments of the sub-stage.

2. =The stage= of Stands A, I, Ia and II is round, revolving and centering. The centering arrangement consists of two small thumb-screws so situated at the sides of the stage as to control motion of the stage in all directions, thus to a limited extent serving the purpose of a mechanical stage.

=The other microscope= stands have square immovable stages, sufficiently large for general microscopic work. For the examination of very large sections two instruments are manufactured: the _Nebelthau_ sliding microscope (p. 50) and the stand after _Dölken_ (p. 52). The former is for magnifications up to 120 diam, whereas the latter can be used with any magnification.

3. =The sub-stage= carries a plane and concave mirror, the condenser and the diaphragm for regulating the illumination of the object.

=The Condenser= is so adjusted as to concentrate the rays of light about 2 mm above its surface, which is the average thickness of the microscopic slides, under an angle equal to the angular aperture of the highest power objective, which is about 120°.

In the lower power objectives the angular aperture is to be reduced by the iris diaphragm.

To focus the Condenser properly it is adjustable by rack and pinion movement on Stands A, I, Ia, Ib, and by side screw on Stands II and IIa.

4. =The body= of the microscope carries the tube and is fitted with two adjustments for focussing; a coarse adjustment and a fine adjustment. The smooth working of these adjustments is one of the chief requirements of a good microscope.

=The coarse adjustment= consists of rack and pinion and moves the tube of the microscope in a vertical groove with the least possible friction. The teeth of the rack and pinion are set obliquely to the axis of the tube and are so adjusted that two teeth of each are always interlocked, thus avoiding all possibility of slipping or loss of motion in the movement.

=The fine adjustment= consists of a micrometer screw which moves the tube and arm of the microscope supporting the coarse adjustment vertically upon a triangular column. This column is virtually a continuation upward of the upright support of the base of the microscope. Around the column is a broad collar so accurately fitted that it moves smoothly upon it with a minimum of friction and still without lateral motion, the movement being controlled by means of a micrometer screw at the top of the column. The head of this micrometer screw, a section of which is shown in the accompanying figure, is milled and is graduated in such a way as to indicate the exact degree of motion of the microscope tube which is accomplished by turning the micrometer screw, each division of the graduation corresponding to a motion of the tube through 1/100 millimeter, and a complete revolution of the screw corresponding to a motion of the tube through ½ millimeter. The accuracy of this adjustment and the smoothness of its motion must be conceded to be a triumph of mechanical skill.

=Stands A.= and =I.= are fitted with a =new fine adjustment= device (one division on the micrometer screw corresponding to 1/1000 mm.) which is fully described on pages 25-26.

5. =The tube= of the microscope encloses a second tube, or draw-tube, which latter carries the eye-piece, and is so graduated as to indicate the exact length of tube in use at any time. The lower end of the tube has a thread into which the various objectives or a nose-piece screw. Tube and objectives are provided with the so-called "Society screw".

=The nose-piece= has now become an almost indispensable part of a working microscope. It can, however, be used to best advantage only on such stands as are provided with a coarse adjustment by rack and pinion. Aside from the advantage derived from the rapid changing of objectives, which it permits, it is so accurately made and centered as to materially facilitate the focussing of the various objectives. It is only necessary to focus with the fine adjustment to obtain a view of the same microscope field which had been under observation before the change was made.

As it is necessary for this purpose that the objectives should be accurately adjusted to the nose-piece, it is very desirable that in ordering an instrument its nose-piece should be ordered at the same time if one is to be used, as subsequent ordering may necessitate the return of the stand and objectives to us.

=Stands A, I, Ia, Ib, II, IIa, IIb and III= are those which are best suited to fine microscopical investigations. Among them the physician and bacteriologist will find an instrument entirely suited to his particular needs.

=Stand III= is now provided with rack and pinion adjustment.

=Stands IV and V= are small instruments, which serve nevertheless many purposes where the more elaborate outfits are unnecessary. They make excellent laboratory stands for elementary courses in microscopy.

In =Stands IV and V= the coarse adjustment is by means of sliding tube. They are all provided with fine adjustment by micrometer screw.

=Stand VI= is provided with rack and pinion adjustment only. It has a large stage, and is particularly intended for searching for trichinae and for similar examinations where a very strong durable stand is desired and where the use of high power objectives is unnecessary. It may also be useful as an auxiliary stand for purposes of demonstration in laboratories.

=Stands III, IV, V, VI= have no joint for inclining the body.

=Stands A, I, Ia, Ib, II, IIa, IIb, III, IV= have mahogany cases (provided with a nickelled handle), in which the microscopes stand.

=Stands V and VI= are laid in mahogany boxes.

These cases are furnished with the microscopes without extra charge, when a =complete outfit=, including oculars and objectives is purchased.

Object clamps and test objects accompany every microscope.

The objectives to Stands A, I, Ia, Ib, II, IIa, IIb are in brass boxes; those for Stands III, IV, V and VI are in morocco cases.

=Illuminating Apparatus.=

=a. Illuminating Apparatus of Stands A and I.=

The apparatus includes the following parts:

Cylinder iris diaphragm. Swing-out condenser. Diaphragm carrier with iris diaphragm. Plane and concave mirror.

The cylinder iris diaphragm comes into play when the condenser is swung out of position. To do this the diaphragm carrier is turned to the side as shown in the diagram, a small knob is pressed, which liberates the condenser, and the latter is swung out to the side.

The regulation of the cylinder iris diaphragm is accomplished by means of a lever. Before the condenser is swung back into position the cylinder iris should be opened to its fullest extent. The lower iris diaphragm is for use in connection with the condenser only. It is regulated by means of a small knob. A horizontal rack and pinion arrangement permits oblique illumination, and a vertical rack and pinion permits adjustment of the whole sub-stage. By these means a most perfect control of the illumination of the object is assured. Ground or colored glass discs may be inserted above the iris diaphragm if modification of the light is desired. =$30.--=

_This illuminating apparatus may also be fitted to Stands Ia and Ib._

=b. Illuminating Apparatus of Stands Ia and Ib= (p. 30, 32, 34).

The following are the parts of this apparatus:

Cylinder diaphragm with 3 stops of different apertures. Condenser. Diaphragm carrier with iris diaphragm. Plane and concave mirror.

To substitute the condenser for the cylinder diaphragm the diaphragm carrier is turned to the side and the cylinder diaphragm is drawn out of the sleeve which holds it in position and into which the condenser readily fits. The diaphragm carrier is then turned back into position and the amount of light regulated by manipulating the knob controlling the size of the iris. The whole sub-stage may be raised or lowered in the optical axis by means of a rack and pinion, and a similar arrangement permits lateral illumination by moving the iris diaphragm in the horizontal plane.

Ground glass and colored plates may be inserted above the iris diaphragm. =$24.--=

=c. Illuminating Apparatus for Stand II and IIa= (p. 36 & 38).

The condenser and iris diaphragm form one piece, giving central but no oblique illumination. The whole apparatus may be raised and lowered in the optical axis by means of a screw. The cylinder diaphragm may be inserted in place of the condenser. A ring below the iris diaphragm permits the insertion of glass discs for the purpose of modifying the light. =$12.--=

=d. Illuminating apparatus for Stand IIb= (p. 40).

The same as for II and IIa fitted in a fixed sleeve; without the side-screw. =$10.--=

=e. Small Illuminating Apparatus.=

The small illuminating apparatus consists of a somewhat smaller condenser with iris diaphragm and can be adjusted to the Stand IV, when it has the cylinder diaphragm. =$8.--=

A cylinder iris diaphragm can be furnished in place of the ordinary cylinder diaphragm of Stand II, IIa and IIb at an additional cost of =$6.--=

Stand III can be had with iris diaphragm fitted in stage, in place of the wheel diaphragm (see page 43) Additional price =$6.--=

=_Complete Microscope Outfits._=

The outfits comprised in the following pages are made up with achromatic objectives, which suffice for all ordinary needs.

We are glad to supply any other combination of eye-pieces and objectives which may be preferred. The price of each outfit may be readily computed by adding together the cost of its various items.

Microscope =stands=, without objectives, will not be sold separately.

=Stand "A".=

Universal Microscope.

In the construction of our new stand "A" we have taken special care to enlarge all the parts proportionately in order to secure strength and stability, at the same time adding to the beauty of the instrument.

The upper pillar of the microscope is shaped in such a way as to form a convenient handle; and to increase the free working space over the stage, thereby allowing the examination of very large specimen and culture plates. A specially constructed mechanical stage larger than No. 98 may be attached, which is adapted for slides up to 2×4 inches (50×100 mm).

The extra large dimensions of all the main parts of this microscope such as the base and stage etc., allow that freedom of movement so desired in a stand for photo-micrography.

Both the body tube and graduated draw tube are very wide and permit the use of low power objectives to cover specimen of large extent; for the same reason the opening in the stage is very wide but can be narrowed down by a stop.

The most important innovation on the microscope is the new fine adjustment device, which is unexcelled both in solidity of construction and accuracy of movement, representing the highest attainment of the designers and mechanics skill.

Sectional cuts of this unique arrangement are shown in illustration (p. 26-27).

All that can be seen on the exterior are two small milled heads mounted below and somewhat back of the two larger knobs controlling the rack and pinion (coarse) adjustment of the microscope. The knob on the right side is provided with a graduated drum _r_, indicating the movement of the fine adjustment.

The two knobs with drum are mounted on an axle _a_, which in its central portion is enlarged and provided with a worm gear. The latter in its turn drives the gear wheel, _d_. A spiral spring pressing against one of the journals into which the axle is mounted prevents any lost motion in the worm gear. Mounted on the same shaft with the gear-wheel _d_, is a heartshaped cam _f_. On this cam rests the steel roller _g_, fitted on the support _k_, which in its turn carries the microscope tube. By its weight and a spiral spring the latter presses on the cam _f_, and effects a direct vertical movement.

The periphery of the heart shaped cam _f_, is exactly symmetrical and mathematically correct. The distance traversed by its curved sides from the lowest to the highest point and vice versa is 3 mm. There are cut 60 teeth in the entire periphery of the gear-wheel _d_; the number corresponding to one side of the heart-shaped cam or 3 mm elevation, are 30 teeth, therefore 1 tooth means a movement of 3/30 mm or 0,1 mm.

This in turn requires one complete revolution of the axle _a_, the drum of which is graduated into 100 parts. The value of each division on the drum is therefore 0,1/100=0,001 mm.

This micrometer fine adjustment is exceedingly accurate and reliable, and besides it has the following advantages;

By virtue of its unique construction the movement is continuous, there is absolutely no limit to the motion of the micrometer screw, which may be turned forward or backward as the work requires.

This movement extends in exact ratio to the revolution of the cam for a distance of 3 mm. As another advantage we may mention, that it is almost impossible to break the coverglass of the specimen with this fine adjustment.

Should the objective come in contact with the coverglass and assuming the knob is turned still further then the tube, which is of aluminium and very light would simply rest on the specimen, without breaking the coverglass, as the latter will easily stand the small pressure of the tube and the fine spiral spring.

No. $

1. New microscope stand "A" inclinable with hinged joint and clamping lever, fitted with round revolving centering stage, coarse adjustment by rack and pinion, new fine adjustment by micrometer-screw (each division 1/1000 mm.) Wide tube, draw tube with millimeter scale. Large illuminating apparatus with swing-out condenser and cylinder-iris diaphragm =120.--= Apochr. 16, 8, 4, oil-imm. 2 mm. N. A. 1,30 =204.--= Compens. ocular 4, 8, 12, 18 =34.50= Compens. ocular No. 6 with micrometer and drawing ocular No. 93 =18.50= Large mechanical stage No. 99, for object slides up to 2×4 inches =32.--= Triple nose-piece =8.--= ------------ Magnif. 70--2250. =417.--=

2. The same stand and illum. apparatus; Object.: 2, 4, 6, oil-imm. 1/12, N. A. 1,30 Ocul. 0. I. III. IV. V. microm. ocul. II. Triple nosepiece =210.--=

Stand I.

3. =Large microscope=, inclinable, with hinged joint and clamping lever and fitted with round revolving centering stage. Coarse adjustment by rack and pinion, new fine adjustment by micrometer-screw, the head of which is graduated each division = 1/1000 mm. Draw-tube with (see page 25-26) millimetre scale. Large illuminating apparatus with swing-out condenser and cylinder iris diaphragm (illustrated on page 21). Mechanical stage, No. 98. Triple nose-piece. Drawing eye-piece, No. 93. Micrometer eye-piece, No. 84. Achromatic objectives Nos. 1, 3, 6. Oil-Immersion 1/12, N. A. 1,30. Eye-pieces 0, I, III, IV, V. Magnifications 12--1300 =236.--=

4. =The same= stand and illuminating apparatus. Triple nose-piece. Micrometer eye-piece, No. 84. Drawing eye-piece, No. 93. Objectives 2, 4, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV, V. Magnifications 33-1300 =210.--=

=The stand= and illuminating apparatus without objectives, oculars and nose-piece =112.--=

=Stand Ia.=

4a. =Large Microscope=, of smaller size than Stand I, fitted with horseshoe foot. The stand is inclinable and fitted with revolving centering stage, coarse adjustment by rack and pinion, fine adjustment by micrometer screw with scale. Draw-tube with millimetre scale. Large Illuminating Apparatus (Cf. p. 22, b) with rack and pinion, and iris-diaphragm with oblique movement. The cylinder-diaphragm and condenser may be readily substituted for one another. Triple nose-piece. Objectives 2, 4, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV, V. Magnifications 33-1300 =160.--=

4b. =The same= with Illuminating Apparatus. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV. Magnifications 60-1000 =148.--=

4c. =The same= with Illuminating Apparatus. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/10, N. A. 1,30. Eye-pieces II and IV. Magnifications 70-730 =136.--=

=Stand= with Illuminating Apparatus, but without objectives, eye-pieces and nose-piece =76.--=

=The same= with Illuminating Apparatus, Swing-out Condenser and Cylinder Iris-diaphragm (p. 20, a) =82.--=

Mechanical stage No. 98 can be fitted to this stand; price =28.--=

=Stand Ia= with English foot.

4d. =Large Microscope= differing from the foregoing (Ia) stand only in being provided with an English foot, which makes the stand somewhat steadier and lighter. The prices and combinations are otherwise the same.

Dr. P. G. Unna of Hamburg uses this microscope in his laboratory.

The stage revolves and centres. The illuminating apparatus is that described on p. 22, b. Triple nose-piece. Objectives 2, 4, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV, V. Magnifications 33--1300 =160.--=

4e. =The same= with the illuminating apparatus. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV. Magnifications 60--1000 =148.--=

4f. =The same= with illuminating apparatus. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/10, N. A. 1,30. Eye-pieces II, IV. Magnifications 70--730 =136.--=

=The stand= with illuminating apparatus, but without objectives, oculars and nose-piece =76.--=

=The stand= with swing-out condenser (p. 20, a) =82.--=

Mechanical stage No. 98 can be fitted to this stand; price =28.--=

=Stand Ib.=

5. =Large Microscope=, which differs from Ia only in the stage. The stage is fixed and square. The stand is inclinable and has a hinged joint and clamping lever. Draw-tube with millimetre scale. Coarse adjustment by rack and pinion, fine adjustment by micrometer screw with graduated head. Illuminating Apparatus, same as Ia (p. 22, b). Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV. Magnifications 60--1000 =142.--=

6. =The same= with simplified Illuminating Apparatus (p. 22, c). Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/10, N. A. 1,30. Eye-pieces I, III, IV. Magnifications 60--730 =120.--=

7. =The same= without Illuminating Apparatus, with Cylinder-diaphragm. Double nose-piece. Objectives 3, 7. Eye-pieces I, III. Magnifications 60--450 =74.--=

8. =The same= without Illuminating Apparatus and without nose-piece. Objectives 3, 7. Eye-pieces I, III. Magnifications 60--450 =68.--=

=Stand= without objectives and eye-pieces, without illuminating apparatus and without nose-piece =46.--=

=Stand= without objectives and eye-pieces, with illuminating apparatus, without nose-piece =70.--=

=The same= with illuminating apparatus, with swing-out condenser and cylinder iris-diaphragm (p. 22 a) =76.--=

=Stand II.=

9a. =Medium Size Microscope=, inclinable, with revolving centering vulcanite stage, coarse adjustment by rack and pinion, fine adjustment by micrometer-screw. Draw-tube with millimetre scale. Illuminating apparatus and iris- diaphragm with lateral screw for raising and lowering. A ring under the iris diaphragm serves to hold a ground glass or colored disc. The illuminating apparatus and cylinder diaphragm are easily interchangeable. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/12, N. A. 1,30. Eye-pieces I, III, IV. Magnifications 60--1000 =126.--=

9b. =The same= with Illuminating Apparatus. Triple nose-piece. Objectives 3, 6, Oil-Immersion 1/10, N. A. 1,30. Eye-pieces II, IV. Magnifications 70--730 =114.--=

9c. =The same= without Illuminating Apparatus. Triple nose-piece. Objectives 3, 6, 8. Eye-pieces I, III. Magnifications 60--550 =90.--=

9d. =The same= without Illuminating Apparatus. Double nose-piece. Objectives 3, 7. Eye-pieces I, III. Magnifications 60--450 =72.--=

9e. =The same= without Illuminating Apparatus and nose-piece. Objectives 3, 7. Eye-pieces I, III. Magnifications 60--450 =66.--=

=Stand= with Illuminating Apparatus and Iris-diaphragm, without objectives, eye-pieces and nose-piece. =54.--=

=The same stand= with Cylinder Diaphragm =44.--=

=Stand= with illuminating apparatus, swing-out condenser and cylinder iris diaphragm =60.--=

=Cylinder iris diaphragm= (Cf. p. 23) =6.--=

=Stand IIa.=