Microscopes and Accessory Apparatus Part 3

[Ill.u.s.tration]

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 subst.i.tute 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 k.n.o.b 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 gla.s.s 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 gla.s.s 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.=

[Ill.u.s.tration: 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.--=

[Ill.u.s.tration: Cylinder iris diaphragm.]

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.--=

[Ill.u.s.tration: Iris diaphragm fitted to stage of stand III.]

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.

[Ill.u.s.tration: Stand A.--Universal Microscope.]

=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 s.p.a.ce 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 24 inches (50100 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 ill.u.s.tration (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 k.n.o.bs controlling the rack and pinion (coa.r.s.e) adjustment of the microscope. The k.n.o.b on the right side is provided with a graduated drum _r_, indicating the movement of the fine adjustment.

The two k.n.o.bs 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.

[Ill.u.s.tration]

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 covergla.s.s of the specimen with this fine adjustment.

Should the objective come in contact with the covergla.s.s and a.s.suming the k.n.o.b is turned still further then the tube, which is of aluminium and very light would simply rest on the specimen, without breaking the covergla.s.s, as the latter will easily stand the small pressure of the tube and the fine spiral spring.

[Ill.u.s.tration]

No. $

1. New microscope stand "A" inclinable with hinged joint and clamping lever, fitted with round revolving centering stage, coa.r.s.e 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 24 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.--=

[Ill.u.s.tration: Stand I.]

Stand I.