Description

Offered for sale is an antique binocular brass microscope by English makers C. Baker of High Holborn, London with the instrument most likely dating to around the 1860 period.  The cosmetic condition is generally acceptable, with some age and use appropriate signs of wear to the finish on the instrument and blemishes to the lacquer-work, which is probably most noticeable on the foot and main Wenham tubes in a few places.  It is however over 160 years old and has the right time worn look for its period and no doubt quite a back-story.  Being a large microscope with quite an imposing sense of scale and of course its signature double Wenham tubes, it’s also an excellent proposition for display, say on a desk-top or other suitable setting such as a home office, especially when set up with an antique slide.  It’s also usable when everything is set up and aligned correctly producing some nice bright images with its current set of optics.

Background to C. Baker, London – source Microscope Museum

The business of Baker was founded in London in about 1765, Charles Baker, who was born in 1820, giving his name to the company from about 1851. When Charles Baker died in 1894 the firm continued under the same name but run by the Curties family until it became, in 1936, Charles Baker & Co. and subsequently, sometime in the 1940s, C. Baker Ltd. The firm’s address mostly given as 244 High Holborn, London (but sometimes 243 and 245, sometimes in combination). The firm produced optical and surgical instruments. In 1963, Vickers acquired the C Baker Ltd microscope factory and a new company called Vickers Instruments was formed. The microscope in this listing is signed with ‘BAKER, 244 High Holborn, London’ may be be a version of Baker’s compound microscope No. 2 with the option of double Wenham tubes fitted. The instrument isn’t numbered and dates to c. 1860.  

Turning to the main technical details of this Victorian binocular bar-limb microscope, we have the following:

1)  Y-shaped tripod foot construction attached to wooden base-plate for extra stability.  Foot in lacquered brass with large twin uprights to pivot, with bar-limb form and lacquered brass finishes to the upper parts of the instrument.  The microscope is inclinable, holds position well on adjustment and can be manually tightened at the pivot point as may be required. Working height as shown is around 19 inches when used with the 2 inch objective with high working distance.

2)  A binocular eyepiece unit in Wenham configuration with the Wenham prism in its carrier in good clean condition giving good bright collimated images to both tubes, provided the Wenham prism is correctly aligned.  Note: the Wenham prism box can rotate and if it moves out of alignment, the images to left and right eyepieces will separate – this can be easily corrected by re-aligning the Wenham prism via slight rotation.  

There’s a pair of top-hat eyepieces giving around 6x magnification. There’s also a second paid of eyepieces marked as “C” which will be 8x magnification.  The instrument also has eyepiece draw-tubes operated by an rack & pinion system, which requires attention although it can be moved manually with care – see section on condition issues later in listing.

3)  The instrument’s main coarse focus is controlled by a set of large brass thumb-wheels with smooth action.  The bar-limb design comprises a triangular section coarse focus limb in brass pinion box.  The coarse focus has the older style straight cut rack, which supports dating to around the 1860 period.  Travel and focus are both very good with positive feel and good tightness, with the optical tubes holding in position as they should throughout their working range.  Fine focus is via a single brass thumb-wheel at the rear of the optical tubes positioned on the bar, acting on the nose-piece only, that has a small range of adjustment with smooth action.

4)  There’s three brass objectives lenses as under, all by C. Baker in brass canisters:

– 2 inches – about 3x magnification (some internal contamination**)
– 2/3rds inch – 10x magnification
– 1/4 inch – 25x magnification

** I have therefore also added a later 1.5 inch brass objective by Baker

The objective lens and eyepieces supplied therefore provide an effective magnification range of around 18x to 200x and it’s pleasing to note the RMS fitment, so plenty of other objectives should also fit the instrument. 

5)  The stage is of a square design in brass with some signs of surface patination to the top-plate, which is on a dovetail slider with smooth movement and holds position well on adjustment.  There’s mechanical adjustment for both x and y-axes, with smooth movement from the straight-cut rack & pinion and screw adjustment mechanisms.  It’s fitted with a ledge for holding slides which works well, along with a couple of sockets for stage clips or stage tools.

6)  Sub-stage there’s a plug-in wheel of stops that friction fits into a brass ring-mount.  The brass mount is 39mm diameter and fits in its own sub-stage mount, with easy removal as required.

7)  Lighting is provided by a large plano-concave mirror in a brass carrier that sits in a gimbal mount slider fitted to the limb tail-piece, with height & swing adjustment and silvering in very good condition to both sides and reflectivity that’s perfectly adequate.

Accessories:

– Original wooden case with brass carry-handle, working lock & key and internal drawers & racking
– Bull’s-eye condenser (not shown in listing photos) in brass with 1.5 inch convex lens
– Wheel-of-stops with 5 aperture positions 
– Second alternate rotor for wheel-of-stops with 5 darkfield positions
– Nicol prism polariser and nose-piece analyser
– Sub-stage condenser
– Alternate darkfield top lens for sub-stage condenser
– Large optical tube insert for monocular viewing
– Eyepiece graticule – currently fitted to one of the 6x eyepieces
– Some test slides, stage micrometer and opaque specimen mounts all in the top drawer

Notes on Condition:

1)  The mechanical eyepiece draw-tube action requires some attention, however it is usable with care and it’s a control that’s usually set, then left in position, i.e. not in constant use unlike say the focus mechanisms.  There is one small screw missing from the left side draw-tube pinion box.
2)  Some of the brass screws and fixings in various places on this antique instrument are worn and have therefore been replaced with more secure fixings. 

In summary, this is a clean and visually stunning example of an antique Victorian bar-limb design microscope, with the popular Wenham double-tube binocular system by respected London makers C. Baker.  This example with its comprehensive set of accessories and period case, may therefore appeal to buyers seeking an imposing brass instrument by a good English maker for use and/or display purposes.  

For shipping, the instrument and case will be very well packed and dispatched by insured courier upon receipt of cleared funds.  

Thanks for looking.