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June 22 1893


Serial number: 3102




Edinburgh B MicroscopeThis compound microscope arises from a Continental Horseshoe foot of the form used by Watson and similar to those used by most European microscope makers of the time. The oxidized brass finished horseshoe gives rise to a lacquered brass round pillar. It is signed on the rear top of the horseshoe foot: 'W. WATSON & SONS, 313 HIGH HOLBORN, 'LONDON'. The serial number 3102 is engraved on the back edge of the horseshoe foot.

The plane and concave mirrors are housed in a lacquered brass casing attached to an oxidized brass gimbal. The mirror support slides inside a slot of the oxidized brass swinging tailpiece.

Edinburgh B understage The substage support, separate from the mirror tailpiece, is attached to the underside of the stage and the entire substage assembly can pivot out of the optical axis on a hinge. When in normal position a brass screw on the opposite side of the stage bottom accepts the catch that holds the substage assembly in position. In contrast to the 'H' model, the substage is a simple sleeve and the condenser must be focused by sliding it manually up or down in that sleeve. There is no mechanism for centering the condenser. With the instrument is a single condenser housing with condenser with an iris diaphragm and a filter/stop holder (stops missing). This condenser is unsigned.

The Stage of this model is a plain flat stage with brass stage clips.

edinburgh B microscope Coarse focus is by diagonal rack and spiral pinion whilst the fine focus is via a long lever controlled from the top edge of the rear part of the arm. The knurled lacquered brass fine focus knob is calibrated and numbered from 0-9.

The outermost main optical tube is 1.2 inches outside diameter and is about 5 inches (130 m.m.)long.   There is one brass calibrated drawtube with an outer diameter of about 1 inch with calibration lines every 1 cm. The inner draw tube accepts the narrower 23 mm eyepieces. The maximum mechanical tube length is about 9 5/8 inches (245 m.m.) There is one eyepiece with the instrument labeled 'B'.

All the rack and pinion fittings have the capacity for adjustment in the event of wear, as do the the slides in which the tubes and substage travel. Every part of this microscope works like it did 100 years ago.



Accessories currently with this microscope include the single eyepiece mentioned above, the condenser, and the objectives noted below.

Objectives with this microscope at this time include:

  • 2 inch Watson with 0.17 n.a. which makes it a holoscopic, though not labeled as such.
  • 2/3 inch, n.a. 0.28 which makes it a parachromatic, though not labeled as such
  • 1/6 inch Parachromatic

Options for this microscope at the time of its manufacture included a finer grade of graduations to the fine adjustment but major upgrades to the stand otherwise would have changed it to a 'C' or 'D' stand.

The stand is in excellent condtion, though it lacks the small registration piece for the fine adjustment. Although it came to me with many parts quite loose, the built-in adjusting screws allowed me to tighten everything up perfectly so the microscope now works as well as it did 112 years ago.



edinburgh B engraving from 1898

The Edinburgh stand, is a model apparently devised in 1887 with the advice of an Edinburgh professor, Dr Alexander Edington, a lecturer on bacteriology at the University of Edinburgh.   The first entry in the Watson Delivary Books for an Edinburgh Student Microscope was on November 29 1887. The first with compound substage was listed on January 20, 1888.

It preceded the Van Heurck and later Royal models, and indeed was the inspiration and basic stand on which both were based. The Edinburgh stand went through several iterations and improvements over the years. The various Edinburgh stands were at first indicated in the Delivery Books only by description (e.g. Edinburgh Student Microscope with Rack), then during 1889 by the numbers 1,2,3, and 4, but by 1889 the catalog referred to them by letters and these were used in the delivery books from early 1890 onward. The letters A,B,C, and D replaced the 1,2,3,and 4.   In 1892, came the E,F,G, and H, which were identical to the first four except for having a tripod foot instead of the (initially standard) horseshoe foot.  

The Edinburgh A,B,C and D models were reported in the 'English Mechanic and World of Science' in August of 1889 and were also listed in the 'Ninth' edition of Watson microscope catalogs which has an introduction dated 1889.  For a summary of the chronology of these events, please see  below.

Edinburgh A The A and E had a push-pull coarse focus and the standard Watson long lever fine focus. The condenser sleeve was built into the bottom of the stage. There was a swinging tailpiece with mirror riding in a slot, just as the example of the B in this collection.

Edinburgh BEdinburgh FThe B and F were identical to the A and E but featured the addition of diagonal rack and spiral pinion coarse focus instead of the push-pull coarse focus.

Edinburgh CEdinburgh GC and G then featured the addition of a separate 'compound' substage with diagonal rack and pinion focusing and controls for centering the condenser sleeve.

Edinburgh DEdinburgh H Finally, on the D and H, was added the rack and pinion mechanical stage, which became standard on the Royal much later.

mechanical draw tube for Edinburgh In 1893, an option was to add a second draw tube which was controlled by rack and pinion. The Royal introduced later, was actually an Edinburgh D or H, with the mechanical draw tube standard and the option of a substage fine focus as supplied on the Van Heurk models. Other options, including Nelson's unidirectional mechanical stage can be seen on the Edinburgh accessory catalog page.

As can be seen below, the 'B Edinburgh Student' microscope shown on this web page was entered into the Watson Sales/Delivary book on June 22, 1893, about six months after the  first 'H' model was listed by letter, which was first recorded November of 1892, though it is clear from the Journal mentioned above, and the 9th catalog, that the Edinburgh Student Microscope was known and offered for sale by August of 1889.   The Edinburgh line of microscopes continued to be manufactured as late as 1945. The horseshoe foot became less popular among Watson Edinburgh models and so is much less commonly seen today, and when seen, as is the case here, is usually found on earlier stands.

sales record


The author would like to thank Dr Joe Zeligs and Allan Wisner for help, references and advice on this page.