Watson Fram Microscope

Offered for sale is an antique Fram model microscope in brass by W. Watson & Sons Ltd of London.  Visually it looks like a Fram Mk III model, however the serial number on the tripod 11639 dates to 1910, so this must actually be an earlier Mk II Fram model that's been upgraded with a heavier more substantial Mk III base, which is a useful/sensible upgrade.  For information, see library image for the various Fram variants - all with different tripods - at the end of the listing photos.

While the Fram is slightly smaller than some other Watson models from this period, such as the Edinburgh range, it's still quite an impressive and imposing instrument especially when extended for use.  This example both displays well and is perfectly usable, producing some nice images with its current optics.

Turning to the technical details, the Fram's construction is a brass tripod with cross member and twin uprights supporting the pivot point.  The upper limb is very reminiscent of Watson's Edinburgh model, with the same internal lever fine focus arrangement.  Coarse focus is via rack and pinion which has a good smooth action, with fine focus achieved via a separate thumb-wheel located at the rear of the upper limb, which operates an internal lever system and also works nice and smoothly. The instrument also tilts for inclined viewing and can be tightened at the pivot as required.

With the optics, this Watson Fram microscope comes fitted with a graduated brass eyepiece draw-tube and two quality vintage eyepieces that with good illumination produce excellent images:

- 7x magnification Holos by Watson with integral draw-tube
- 10x magnification - No. 4 period eyepiece - possibly Watson but unmarked

It's got three vintage objectives and a later triple brass turret, with objectives as follows:

- 60mm Beck button objective in brass - very low-power & very high working distance - 2x approx 
- 1 inch by Swift in brass - 6x magnification with period brass canister
- Prior 1/6th inch in brass  - 40x with period brass canister

Overall, the range of magnification available with this Watson Fram Mk III therefore ranges from about 14x to a perfectly respectable 400x.

The stage is square in brass with an ebonite top-later with cut-out typical of the Fram model and there's a pair of brass stage clips which also work well.  The stage has been drilled in several places, presumably for prior over-stage fitment, or similar.

Turning to the sub-stage we have a Watson Abbe-style condenser top-mounted into a brass ring mount which also has height adjustment via rack & pinion and centering via twin brass thumb-screws.  The condenser assembly also has a working iris to control lighting levels.  There's a 35mm swing-out holder fitted, allowing coloured, opaque or dark-field filters to be inserted. 

Lighting is via a plano-concave mirror which is in pretty good condition on its fixed brass support rod, with height and gimbal adjustment and near perfect period silvering to both sides.

This is a good and working example of a Watson Fram model with upgraded tripod giving it better stability in use. There is also a period Watson storage case with this example, which is in time-warp condition with lovely exterior sheen, internal lens rack and working lock & key which is always nice to have.  The case retains its leather carry-handle which is showing some age-related wear but still intact.

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

Thanks for looking.