Description

This listing is for a very nice and usable example of an iconic technical microscope that’s in really good original condition – a retro Watson Bactil from the late 1930s, so manufactured just before the start of WWII and probably an early example with chrome-plated bright-work.  Many Bactil models were used in military, hospital or research settings owing to their technical capabilities and quality construction.  This example however doesn’t seem to carry any such markings for previous military or educational custodians and may have been in private ownership.  It has retained most of its original condition, with just some scratching to the pain-work in the usual places owing to it being taken in and out of its case umpteen times over the the last 88 years or so, meaning it’s a remarkably good find and one for a collector or connoisseur of the Watson brand.

Don’t confuse Watson’s Bactil model with its smaller brother the Watson Service model – the Bactil is a much bigger (and heavier) model, the largest that Watson produced in this era.  Look at the size of the objective lenses compared to the size of the Bactil microscope itself – that size disparity gives you an idea of the sheer scale of the Bactil model and it’s also very heavy with solid steel construction and both mono and binocular options plus the inclination unit, so very complete in terms of optical configuration.  Overall, it’s a real brute of a microscope with a great retro look about it.

This example is serial number 65792 which dates its manufacture to around 1938.  It’s got a comprehensive technical configuration, some nice accessories and a compliment of objective lenses offering a useful magnification capability.  The black painted finish is generally in good condition with just the aforementioned chipping otherwise the paint finish has a good level of sheen to it.  The bright-work components being nickel/chrome plated have also polished up really well as I hope the listing photos demonstrate. 

In terms of construction, we have a heavy V-shaped pre-1950 style iron foot with twin uprights to the main pivot, with lever tension adjustment and Lister-type upper limb also in iron.  The stage is attached to the limb tail-piece as are the sub-stage fittings and all-in-all a very heavy stable design.

In terms of technical functions, this Watson Bactil has rack and pinion coarse and thumb-wheel fine focusing, both of which move nice and smoothly with no detectable signs of wear, holding position on adjustment with no slippage. 

This example is supplied with two pairs of 6x and 10x magnification eyepieces for the binocular unit and a 10x for the monocular.  The binocular unit is in good working condition with inter-ocular adjustment via thumb-wheel control and well collimated bright images to both eyepieces.  These binocular units are rated at +1.5x magnification, so effectively you have 9x and 15x magnification at the eyepieces.  There’s also a monocular unit with matching serial number 65792 and there’s the inclination unit – all optical components are reasonably clean for their age.

The instrument can be used in the following optical configurations:

– binocular
– monocular
– angled binocular using inclination unit – adds +1.5x magnification
– angled monocular using inclination unit – adds +1.5x magnification

The available configurations are all demonstrated in the listing photos.

There is a rotating chromed nose-piece shown which has since been upgraded to a quadruple Watson turret, which clicks into position positively as it’s rotated.  This now comes supplied with a set of progressive magnification period objective lenses suitable for a research-grade Bactil model, which are mainly by Watson and are shown in close-up in one of the listing photos, as follows:

– Lomo low power high working distance – 3x magnification
– Watson para 16mm – 10x magnification
– Watson para 4mm – 40x magnification
– Watson Holos – 100x – oil immersion required

Note: various other objectives are shown in some of the listing photos, but it’s the ones detailed above that will be supplied with the instrument.

There’s therefore the effective magnification range with all the supplied optics and including the effect of using the inclination unit is 18x to a theoretical 1,500x when using oil immersion with the highest power optical configuration.

The fully mechanical circular specimen stage is a really well-engineered feature that has rack and pinion & screw systems that move both the x-axis and y-axis smoothly via thumb-wheel adjusters on the right-hand side of the stage, together with silvered vernier measurement scales for both axes.  There’s a two-part stage-clip system for holding slides in place during viewing, which retains adequate resistance in the armature in the right-hand clip to hold a slide firmly in place while the x and y-axes are being moved around under inclined viewing conditions.  Note the top part of the mechanical stage can be removed easily for cleaning by just winding the y-axis forward and gently pulling it off the dovetails.  Note:  this model of stage doesn’t rotate – you would need a Watson Patna model from this period for the stage rotation feature.  There’s also the large square non-mechanical stage as shown that’s fitted with a couple of brass stage clips.

Below stage there’s a Watson universal No.1 condenser with working iris in a dove-tail mount as shown.  This condenser arrangement is known as the Research sub-stage for this model and allows quick change-over of condenser types, or removal altogether when using very low power magnification.  There’s also a dark ground condenser unit on a separate dovetail slider.  The sub-stage has a rack and pinion system for condenser vertical height adjustment also with centering via twin thumb-screws and there’s adequate reach for oiling to the back of slides as may be required for very high magnification work.  There’s also a swing-out filter holder that push-fits to the underside of the condenser for adding coloured, opaque or dark-field filters along with a second working iris.  

For illumination, this example is fitted with a double-sided plano-concave mirror which is on an adjustable arm and gimbal set-up that slots into the underside of the limb tail-piece.  The mirror has good silvering to both sides.

All-in-all a good solid and very clean example of an inter-war Watson Bactil with its comprehensive technical set-up, nice set of accessories, period look and good cosmetic condition.  This example would be one to add to the collection especially for those collectors looking for a large imposing piece with that all-important retro look and technical capability.  Please note that this example has its correct storage case of substantial dimensions, with internal racking for eyepieces, metal carry-handle and working lock and key.

With all that metal and case it’s also a real heavyweight item for shipping, weighing over 15kg with packaging which accounts for the shipping cost, so it will be sent by insured courier upon receipt of cleared funds.  

Thanks for looking – please check out my other listings.