MODEL:

THE PARAGON MICROSCOPE

DESCRIPTION:

This Wale limb microscope, which is well made, is supported by a special foot in which the grooved limb glides for inclination. The microscope can be clamped at any degree of inclination via a knurled knob on the right side of the foot. The foot is actually one part as opposed to many other smaller Wale limb instruments (including the original) that have two parts grasping the microscope limb between them. The grooved limb slides between two sets of four points, the depth of which is controlled by screws on each side of the support of the foot. The shape of the foot provides extra clearance under the stage for ease of manipulation of the substage apparatus. The foot is signed J. Swift & Son, London.

The substage attaches via a dovetail fitting, to be completely removable if desired. It has focusing by rack and pinion and centering adjustments. There are two condensers. The simpler condenser uses a 1 inch objective, (which is readily removed and replaced), for optics and has a filter holder and iris. The second is the Swift Universal Condenser, complete will all attachments. The plano and concave mirror is on a gimbal that is attached to a slide on the swinging tailpiece that is separate from the substage condenser support.

Coarse focus is by diagonal rack and spiral pinion, while fine focus, on the left side of the microscope is Swift's patented Climax fine adjustment, the control knob being horizontal and very close to the coarse adjustment knob.

The stage can rotate 360 degrees manually and it has separate controls for X and Y motion. Back and forth (Y-axis) motion is by diagonal rack and spiral pinion in the center, while left-right motion(X-axis) is by worm screw. The surface of the mechanical stage has a decorative finish. Two moveable black slide holders are present, which slide in dovetail fittings. One has spring clips to push against the slide the other with clips to hold it down. there is a hinged slide register on one side of the latter. One of the two slide-holders has a upright brass fitting for a stage forceps or other similar apparatus.

Like most Swift instruments, this microscope is provided with many adjustments for wear. There is a double nosepiece objective changer.

In addition to the one inch Swift objective for use as a condenser there are also a 2 inch and a 1/2 inch Swift objective with this microscope. There is no case with it however.

HISTORY OF THE SWIFT 'WALES LIMB' MICROSCOPES AND THE SIDE FINE ADJUSTMENT

The American microscope maker George Wale invented the grooved inclination system which bears his name about 1879. The first illustration of it that I am aware of was published in the American Journal of Microscopy and Popular Science, Vol 4, No 4, Page 93 (1879). In the same year an illustration of its stage was shown in the J. of the RMS, vol II, p624. This illustration, although clearly showing a portion of the Wale limb, accompanied a brief article about rotating stage clips for Wale's stage. The first article in the JRMS fully illustrating the Wale New Working microscope was in 1880, Vol 3, page 1046.

Only one year later, in 1881, the JRMS featured an image of the Swift microscope number 313, showing that the English makers were 'swift' to adopt this design! Swift was so impressed with this design, that, according to Davis as of 1889, they intended to feature it as their primary type of limb; it was therefore available in many models up to and including Swift's biggest Wale limb microscope he called the 'Paragon' Featured above on this page and even much later models of the 20th Century (see below). The advantage of the Wale limb is that the center of gravity, and therefore the stability of the microscope, did not change regardless of the angle of inclination. Swift's versions are an improvement over Wale's design, for more than one reason. First, because in Wale's case the limb groove was just part of an iron casting it did not move smoothly in the groove; in Swift's examples this groove was machined into the oxidized brass limb for smoother operation. Secondly, Swift's design allowed inclination throught the optical axis of the specimen on a slide, meaning that inclination would only change the obliquity of illumination if a source independent from the microscope was directed on the specimen. This led to an increase in experimentation (and popularity) of oblique illumination. No Wale limb microscope is listed in the 1880 Swift Catalog, further confirming its introduction to 1881.

The Wale method of inclination was also incorporated by many other makers both in the U.S.A. and England, including Schrauer, Bausch & Lomb (in their 'American Concentric Microscope'), Watson & Sons, and the ultimate version, the Wenham 'Radial' Microscope by Ross. The Ross Radial microscope provided many adjustments to provide virtually any kind of oblique illumination. Similar elaborate 'radial' arrangements were also made by Beck, Watson, and many other makers, but it was Swift who apparently continued to make Wale limb microscopes longer than any of the other makers, even into the 2nd quarter of the 20th Century.

In 1883 a new version of the Swift Wale limb microscope referred to as the Radial and Inclining Microscope was figured and reported in the JRMS, pp704-706, and then in the November issue of the English Mechanic and World of Science. This version had a removeable substage, including the tailpiece for the mirror. It had holes on the front of each side of the foot for a bullseye condenser or the mirror; having these not move during inclination provided a way to take advantage of varying degrees of obliquity of illumination as the inclination was changed. The mirror could alternatively attach to the tail piece. This was the first Wale limb illustration showing 3 screws in the uprights which rode in the inclination groove. It had a glide-stage in which the slide sat on a holder which could be manually pushed around the stage.

Soon after that, the Paragon, a model with many features similar to the 1883 Radial, but larger, was produced, starting no later than 1885. It was illustrated in Mayall's Canterbury lectures and dated there to 1885. The engraving pictured in Mayall's Lectures on page 87, continued to be used to illustrate the Paragon in the Swift catalogs in all cases where it was found thereafter, despite any changes that might have taken place in its design. This was a common practice as engravings were expensive and time-consuming to produce and often did not reflect the latest model.

In the 1910 catalog an Improved Wales Microscope No 305 which had a focusing substage and mechanical stage and offered other options like concentric fine focusing for the substage, was listed and illustrated but the Paragon, though no longer illustrated, was still offered in the catalog.

In the 1910 catalog it notes:

We make a larger version of this Stand. It is the same size as the 'Best Challenge' and is known as the Paragon.

Because the illustration of the Paragon model never changed, it is difficult to differentiate the later form of Improved Wales model from the Paragon. One way could be that while the Improved Wales is a bit smaller, it has 3 screws riding in the inclination groove, whereas, at least the later versions of the Paragon have four. Apparently another difference was that the later Improved Wales had a protruding pod under the rear of the U-shaped part of the foot.

The Paragon was offered from no later than 1885(Mayall) and is noted in the Swift catalogs from 1891 through at least 1910. After being offered for some 25 years or more, by 1913, it was no longer listed in the Swift catalog.

Although the Paragon model was no longer listed in the 1913 catalog, Wale limb microscopes were produced by Swift into the 1920s at least. These included the Premier, Symposium, and Photographic Petrographic models.

Options included a silvered scale on the rotational stage movement, and a vernier scale for X and Y motions of the mechanical stage. Other options were binocular tubes, and a concentric fine adjustment to the substage.

It appears that the 'Swift Wales' microscopes were offered from no later than 1881* and continued in some form or another through the 2nd quarter of the 20th century. In 1883 Swift offered their 'Radial Inclining Microscope' with a Wale limb. In 1914 an improved version of Wale limb was offered on the elaborate Swift 'Photographic Petrological Microscope'. This tradition continued in the even later (c. 1925), and equally elaborate,Symposium' Model.
The Paragon is one of the larger Wale Limb models as shown in the images here:

*See the JRMS, Series II, volume I, 1881, pages 296-298.

THE SWIFT CLIMAX FINE FOCUS:

Another feature of this microscope is Swift's invention of a vertical long-lever fine adjustment, controlled from the side of the microscope. Control of the fine focus from the side rather than the top of the limb or the tube itself (as were customary before), later became a standard feature of the modern microscope. The idea of fine focus control from the side was probably first used on Powell and Lealand's early stands, although they soon changed its location to the top of the arm because their side-acting designs often led to failure of the mechanism. It was Swift in England, and Berger in Germany who revived this idea with much more reliable designs. Swift called theirs the Climax fine Adjustment

The Climax fine adjustment went through more than one iteration and here is shown an improvement from 1883 published in the JRMS to be used with higher priced microscopes.

In 1886 the version being using with the Paragon at that time was noted in the JRMS.

A later version of the Swift side fine adjustment was called the improved Climax. It was calibrated so that one division on the rotation moved the fine adjustment only 1 micron (0.001 mm). This later version had the knobs elongated and on both sides as seen in the illustration to the left. Berger's design is also illustrated on this site.

The author would like to gratefully acknowledge the kind assistance of James Solliday and Dr Joe Zeligs for valuable catalog information, and advice about the discussion of this instrument.

CONDITION:
This microscope is is superb working condition including the large form of Universal condenser which is complete with all its inserts. There are tiny losses of the black finish on the foot and some minor damage to the lacquer on some of the knobs.