Description

Background to Andrew Ross & Co.

Andrew Ross founded his business in 1830 and, like James Smith, later of Smith & Beck, he collaborated with J.J. Lister, the manufacturing optician who invented a mathematical method of producing high quality objectives. Ross’s early instruments were constructed initially in a fashion similar to other contemporary makers, including a construction style similar to that of the Lister-limb design.  He continued this practice until 1840 when he developed the “bar-limb”, a very stable design and from then on also supported his stands on the classic Y-shaped foot with two upright supports. Andrew Ross died in 1859 and his son Thomas Ross carried on the business. Thomas Ross died about 1870 and the management of the firm was taken over by famous inventor Francis Wenham who was responsible for the development of new models such as the Ross-Zentmayer models in the 1880s and they remained in production into the 1890s until replaced by continental designs such as this example. The Ross company went on to produce optical products well into the twentieth century, although large high-quality microscopes became less important to the firm as the years went by. The firm was called Ross & Co between 1837 and 1841, then Andrew Ross & Co and finally Ross Limited from 1897 onwards. The firm discontinued the production of microscopes in 1906. (Source: Antique Microscopes’ website)

This example of a Ross Continental pattern microscope presents really well with some lovely gleaming brass-work details and some age-appropriate patination here and there, although nothing that significantly detracts from the visual appeal, which is what you’d hope for with an antique instrument of this age.  The instrument’s look and feel is of a quality not found in modern microscopes in that’s it’s fashioned from solid brass, giving it a really weighty feel.  It’s a compact to mid-sized instrument and despite its modest dimensions, appears surprisingly large when coarse focus and draw-tubes are both extended.

Technical details – the construction is a brass tuning-fork shaped foot with twin uprights supporting a pivot and a Continental fine focus pillar and upper limb arrangement.  The coarse focus is by rack and pinion with the newer-style diagonal/helical cut that features on instruments from the 1880s onwards.  The coarse focus has a nice smooth action and holds in position as it should in its working range.  Fine focus is operated via a graduated brass thumb-wheel located at the rear of the main tube which moves the limb, being a vernier screw acting against sprung resistance, also working well. 

In terms of its optics, this microscope has a graduated brass eyepiece draw-tube with nice smooth action that holds position as it should.  It’s supplied with a two eyepieces of 6x and 8x magnification that with correct illumination produce bright age-appropriate images.  It’s also got a double turret and two Ross objectives as follows:

– 2/3rds inch – 10x magnification with correct brass canister
– 1/8th inch – 50x magnification with correct brass canister

I’ve tested the optics with various antique slides and the images produced are perfectly acceptable when using good illumination. The magnification range available with the instrument with its current set of optics will be around 60x to 400x.

The instrument tilts for inclined viewing and holds in position as it should on inclination.  The all-brass specimen stage is circular and rotates (not through a full 360 degrees) with smooth rotation and sufficient damping so that it holds position on adjustment.  There’s also two brass thumbscrews for centering.  The stage is mechanical with an unusual arrangement – the y-axis control is to the right-hand side and there are silvered vernier scales for both axes.  The y-axis adjustment gives about 1 inch of travel in the y plane, with slight notchiness to the action but still perfectly usable.  The x-axis adjustment is via a removable over-stage mechanism, which attaches via a single thumb-screw and a couple of locating pins.  The over-stage is fitted with stage clips for holding slides steady – this also looks like it has a replacement clip to the right hand position.  Overall the mechanical controls provide adequate control of specimen positioning and also hold position on inclination. 

To the sub-stage, we have a twist-action iris in a plug-in friction-fit mount that works well as shown in the listing photos.  Lighting is via a plano-concave mirror in a gimbal mount with swing, rotation and height adjustment, with excellent silvering to both sides. 

The instrument has been very gently dusted and also lightly lubricated with non-hardening grease where appropriate, so that the controls operate smoothly.  This example displays exceptionally well having some lovely brass-work with mellow golden tones which catch the light beautifully.  This antique microscope is very much a usable proposition as well as an antique display piece suited to a library or home office type of setting, especially when set up with an appropriate antique slide. There’s also an original storage case with a plaque on the inside of the door confirming that the instrument was originally retailed by Clarksons of Victoria Street, London.  The case has internal racking, key missing so a cupboard latch has been fitted to keep the door closed and the carry-handle is a modern replacement.

Owing to the weight and delicacy of this antique microscope, it will be partially dismantled, carefully wrapped for shipping and dispatched by insured courier upon receipt of cleared funds.