This Bactil also benefits from an excellent set of period-correct lenses mostly by Watson, an original brass full mechanical over-stage and the correct period hardwood storage case. It's got superb lacquered brass details including the wide tube and all the thumb-wheels which are naturally showing some signs of age-related spotting, but this is very much in keeping with the instrument's age and provenance and adds to its character. The brass-work really catches the sun and glints with a lovely warm yellow/golden hue.
The Bactil is essentially constructed from quality materials, with solid construction, great design and skilled workmanship and in this period many hours of hand-finishing required to produce an instrument of this quality. This example has no significant signs of wear I can see, indicating careful use and ongoing maintenance over its life. It's got a great look and patina with just the right signs of age for a brass example from the 1920s.
On the technical side, both coarse and fine focus move nice and freely with just the right amount of resistance and the instrument holds in position in terms of its main optical tube and on inclination as it should. Turning to the optics, this microscope comes fitted with a graduated brass eyepiece draw-tube that's narrower than those found on most later models of Watson, thereby giving the appearance of a wide-body look to the instrument. There's also some appropriate and very high quality vintage Watson Holos eyepieces that with good illumination produce excellent images as follows. 7x magnification - Watson - 10x magnification - Watson. (Note: these Holos eyepieces have their own integral draw-tubes and would have been a top-of-the-range item in the Watson catalogue).
2/3rd inch - Watson Parachromatic -10x with period Watson brass canister. 1/6th inch - Watson - 40x with period Watson canister - 1/12th inch - Carl Zeiss Jena oil immersion - 100x with period Zeiss brass canister (not tested with oil) - 2mm - Watson Holos oil immersion - 100x with period Watson brass canister (not tested with oil). Overall, the range of magnification provided by this instrument therefore ranges from about 70x to a theoretical 2,000x with very bright illumination and oil immersion. The mechanical over-stage is an original Watson item in brass that locates onto the standard Watson ebonite stage - it has two bolts that fit through the holes in the stage where standard stage-clips normally reside - it's tightened into place with two thumb-screws from below-stage - a very good Watson design.
The over-stage has two armatures for retaining specimens one of which is sprung. This system is excellent for retaining slides during inclined viewing, with freely running x/y controls also offering good control of specimen positioning. Turning to the sub-stage, we have a Watson Holos oil immersion condenser with centering via two brass thumb-screws on a height adjustable rack and pinion mount with right-sided thumb-wheel control and it's also got a swing-out feature allowing easy swapping or maintenance of the condenser unit. There's a working iris to control lighting levels that's currently missing its adjustment lever but still moves freely.
Lighting is via a plano-concave mirror which is in very good condition on its adjustable brass support arm and gimbal set-up with excellent silvering to both sides. There's also a 35mm swing-out filter holder for the addition of coloured, opaque or dark-field filters and you'll see in the listing photos that a 35mm blue daylight filter is currently in use because I've been using the instrument recently with tungsten illumination which the blue filter corrects to natural daylight.
All controls operate smoothly including coarse focus, fine-focus, eyepiece draw-tube, mechanical over-stage, condenser and plano-concave mirror. The instrument has been lightly lubricated and the controls operate with a nice precise feel. This is a great visual and working example of Watson's classic Bactil model in very good condition for a 1920s working example in the sought-after brass finish, making it quite an interesting proposition for a collector. It's in highly original condition with a comprehensive specification, great optics and it's essentially highly collectable and really would make a good centre-piece for a collection of vintage brass-era instruments.
There's also a period-correct Watson storage case with this example, which is also in very good condition for its age with a few shrinkage cracks which is quite normal for Watson cases of this vintage. The case also has a nice original leather carry-handle and an original working lock currently without a key, but it does have s small cupboard latch to keep the door closed.
Thanks for looking - please also check out my other listings if you get a chance. Watson & Sons Ltd Bactil Monocular Microscope in Brass c1927, Cased" is in sale since Tuesday, July 6, 2021. This item is in the category "Antiques\Science/Medicine\Scientific Instruments".
The seller is "arcboutant" and is located in Glasgow. This item can be shipped worldwide.