Description

Offered for sale – a collectable example of a compact antique monocular brass bar-limb microscope by quality makers Murray Heath Opticians of London.   The instrument is signed by the makers but isn’t numbered and according to available literature will date to around sometime in the early 1870s – see image from an 1871 publication “The Microscope” in the listing photos.

Background to Murray Heath Opticians (source: microscopist.net)
The partnership between Robert Murray and Vernon Heath was founded in 1855, with the business going through various guises and owners until 1869 when it was bought back by the founder’s son Robert C. Murray and remained trading as Murray Heath until 1882.  This example of a Murray Heath student bar-limb model dates to the early 1870s under the latter’s ownership.  The firm manufactured good quality microscopes, also assembling some models with bought-in components from other makers.  The firm produced instruments primarily targeted at medical students and middle-class amateur microscopists, becoming well known for their range of compact portable instruments and the overall good quality of their products.

This example of a Murray Heath monocular instrument is their student model and will date to the early to mid 1870s – there’s an image in the listing photos showing this model’s 1871 advertisement.  It’s in original condition and presents really well with some gleaming brass-work details and lovely age-appropriate patination.  It’s survived pretty well over the last 150 years or so and the brass-work still glints when its catches the light and I hope that the listing photos do the instrument justice.  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 feel despite its compact size and a definite presence when extended for use with coarse focus racked out.

Technical details – the construction is a tripod foot in brass with black lacquered finish, with twin uprights supporting a pivot and a bar-limb arrangement.  The foot also has a fitted mahogany base-plate, thereby giving additional stability as well as allowing use on a polished surface or desk-top.  Coarse focus is an unusual arrangement that uses a traditional triangular section bar-limb slider and a chain mechanism driven by the twin thumb-wheels, which has quite a smooth tight action and holds in position as it should through its working range.  Fine focus is not provided on the instrument. 

In terms of its optics, this microscope has a brass optical tube screw-fitted to the bar, which is easily removable.  It’s supplied with an approx. 6x magnification period top-hat eyepiece which produces bright age-appropriate images.

It’s currently got two brass objective lenses which screw into the optical tube one by one.  It’s important to note that the instrument has RMS thread, so there’s plenty of other objectives that will also fit this instrument.  The supplied objectives are by Murray Heath and are as follows:

– 1 inch – 6x magnification
– 1/4 inch – 25x magnification
(with their original brass canisters)

The magnification range currently available therefore is around 36x to 150x.  I have tested the optics with various types of antique and modern slides suitable for polarised light and the images are perfectly acceptable when using good illumination.

This model is fitted with a nicol prism nose-piece analyser and the instrument is set-up of for polarised light microscopy.  The analyser is RMS male/female thread and can be removed from the optical path if not required for non-polarising work.

The instrument tilts for inclined viewing and holds in position through its working range as it should.  The all-brass specimen stage currently has a sliding rest for holding specimens which works well.

Turning to the sub-stage, we have nicol prism polariser with rotation feature that friction-fits into a sub-stage brass mount.  Lighting is via a single-sided concave mirror in a brass gimbal mount with height and and rotation adjustment, with period silvering showing some foxing but still in usable condition.  The sub-stage polariser can be easily removed for non-polarising work.

The instrument has been sensitively cleaned and also lightly lubricated with non-hardening grease, so that the controls operate smoothly.  This example displays really well having quite a presence, with some lovely brass-work details.  The instrument is also endowed pretty well all over with age and use-related patination especially to the tripod foot giving just the right time-worn look for an instrument from the Victorian period.  Overall this example of a Murray Heath microscope is perfectly usable especially for polarised light work and should also make a great display piece, perhaps in a library or home office type of setting, especially when set up with an appropriate antique slide for demonstrating polarising effects. 

I don’t usually do image capture, but on this occasion I’ve put a couple of photos of the Watson antique chemical crystal slide you’ll see in the listing photos (just taken by balancing my iPhone on the eyepiece) showing it under polarised light, then again with the polariser rotated – you get some amazing colour changes with this technique.  The nicol prism polariser and analyser are in reasonably clean condition and would probably benefit from a further deep clean to enhance light transmission.  Extinction is achieved quite well when polariser and analyser are crossed.

There is also an original hardwood fitted storage case with this instrument, which is in good condition for its age with a lock but key absent, so there’s a cupboard latch fitted to keep the door closed and overall still presenting very well with good exterior sheen and period brass carry-handle. 

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.