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 objectives which were both achromatic and aplanatic. 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. Early examples of the Ross bar-limb construction used a triangular bar, which was later replaced by a square one and finally on the largest and heaviest version, a rectangular one. The Ross bar-limb design became the standard for many British microscope makers throughout the second half of the 19th century. Some conservative companies such as Powell and Lealand continued the manufacture of bar-limb microscopes into the 20th century, long after improved continental designs appeared in the market. Andrew Ross died in 1859 and his son Thomas Ross carried on the business. Thomas Ross died about 1870. 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.

This example of an early Ross bar-limb monocular microscope presents really well with some lovely gleaming brass-work details with some age-appropriate patination here and there, which is what you’d hope for with an 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 weighty solid feel and it’s quite a large instrument at over 20 inches in height when inclined for use.

Technical details – the construction is a brass Y-shaped foot with large twin uprights supporting a pivot and a bar-limb arrangement.  The foot has three cork pads on the underside allowing use on a polished surface and there’s also a mahogany base plate that can be attached for additional stability – shown fitted in the listing photos.  The coarse focus is by rack and pinion with the older-style horizontal cut that’s machined into the triangular section slider.  The coarse focus has a nice smooth action and holds in position as it should, also having tension adjustment available.  Fine focus is achieved via a brass thumb-wheel located at the rear of the main tube on the bar, being a vernier screw acting on a lever against sprung resistance, also working well. 

In terms of its optics, this microscope has a fixed optical tube (i.e. without draw-tube) that’s supplied with one vintage approx 6x magnification top-hat eyepiece that with good illumination produces bright age-appropriate images.  It’s currently got a single objective lens which is pre-RMS and has female thread and you’ll see in the listing photos that there’s a brass adapter allowing the objective to be fitted to the optical tube.  The supplied objective will be about 1.5 inches and therefore approx 4x magnification.

I’ve tested the optics with various antique slides and the images are perfectly acceptable when using good illumination. The magnification available with the instrument with its current set of optics will be around 24x.

The instrument tilts for inclined viewing and holds in position as it should on inclination.  The all-brass specimen stage is fully mechanical and is an early version of the mechanical stage by Ross that was only used for a limited period of time, making this quite a rare instrument, with relatively few known examples.  The x/y adjustment thumb-wheels are on the right-hand side and below stage, working very well and hold position on inclination.  The stage top-plate has a rest for holding slides and it will swivel through a full 360 degrees – it’s quite well damped so holds in position on adjustment – it can also slide off its dovetail for cleaning.  There’s also two slots in the stage top plate where accessories such as clips or stage forceps can be located.

Turning to the sub-stage, we have a wheel of stops with smooth rotation and three aperture sizes available.  The wheel-of-stops is held on a mounting plate and secured in position with a single brass screw, allowing easy quick removal and swapping for other sub-stage accessories.  Lighting is via an over-size plano-concave mirror in a brass gimbal mount with rotation and height adjustment, with good period silvering showing a little spidering to both sides as shown. 

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 quite a presence, with some lovely brass-work with rich gold and copper tones which catch the light beautifully.  This antique microscope is very much a usable proposition and would naturally benefit from additional Ross pre-RMS objectives and should also make a stunning antique display piece, perhaps in a library or home office type of setting, especially when set up with an appropriate antique slide. There’s a period double-door hardwood storage case with this instrument in mahogany, with a good exterior finish and just the odd age-related signs of minor shrinkage/warping, which is quite normal for antique instrument cases of this age.  The case has internal racking for lenses and accessories, a recessed brass carry-handle and is missing its keys so cupboard latches could be fitted to help keep the doors closed. 

Accessories:
– live box
– period bull’s-eye condenser

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