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C. 1912


Serial number: 7281




This microscope is not in my collection but is shown here for reference, and for comparison to my Fram model. I am very grateful to Richard Courtier for allowing me to use his fine images of this instrument. This compound microscope arises from a tripod of the form used by Watson in their more expensive instruments with slight differences. Unlike many other examples, this example has NO round brass toes. At the top of the tripod is a lacquered brass plate atop of which are two uprights accepting the trunnion joint with adjustments very similar to many other Watson models like the Edinburgh and Royal. This microscope has parts of its signature in three places. It is signed 'HOLOS, FRAM, 7281 on the lacquered brass cap plate of the tripod on which the uprights erect. It is signed on the black left side of the tripod 'W. WATSON & SONS' and on the other side of the black tripod, 'HIGH HOLBORN, LONDON.' There is a brass screw projecting from the limb which allows registration on the top of the tripod to allow a fixed horizontal position.

The plane and concave mirrors are housed in a lacquered brass casing attached to an oxidized brass gimbal. The mirror fitting slides up or down the swinging tubular brass tailpiece.

hf condenser This example, as was standard for the Holos Fram, has a rack and pinion substage with centering controls for the condenser. The condenser assembly swings aside to allow use of the mirror alone, just as in my Edinburgh H model. It also has Watson's 'Standard Mechanical stage' also usually supplied with the Holos Fram Model.

Coarse focus is by diagonal rack and spiral pinion whilst the fine focus is via a long lever controlled from the top edge of the rear part of the arm. This example has two fine focus knobs, in the Males-Watson two-speed variant. The knurled lacquered brass fine focus knobs are calibrated and have arrows indicating up or down movement. The Males-Watson fine focus was an option for the Fram, Edinburgh, Royal and Van Heurck stands, but was rarely ordered; very few stands with this option are known; it is usually seen added to the Grand Van Heurck, and this addition to a Fram is extremely uncommon.

There are two brass calibrated drawtubes, one controlled by diagonal rack and spiral pinion, nearly the same as the mechanism in the Royal and the Van Heurck, except the Holos Fram has a single knob on the right side for controlling the mechanical drawtube, rather than bilateral controls as in the other two mentioned.

All the rack and pinion fittings have the capacity for adjustment in the event of wear, as do the the slides in which the tubes and substage travel.




hf HF 1902Introduced four years after the basic Fram, the Holos Fram was noted for the first time in the JRMS in 1902, and also first listed in the Watson 1902 catalog. Unlike the basic Fram, the more deluxe 'Holos Fram' came standard with the same mechanical stage and substage as the Edinburgh H; it could even be ordered with a Males-Watson two speed fine asjustment and rack and pinion draw tube. In fact, as of 1902, any option offered for the Edinburgh H was available for the Fram or Holos Fram. The reason that so few Holos Fram stands currently exist is likely that the price of the Holos Fram was only about 10-15% cheaper than the stouter Edinburgh H model. This Holos Fram microscope, with a mechanical draw tube added at extra cost, which was sold on Ebay in 2015, is very much a miniature, and more portable version of the Royal! The Holos Fram was apparently offered from 1902 through at least 1912.

The author would like to acknowledge the help of Dr Joe Zeligs in supplying some of the information on this page. I would also like to thank Richard Courtier, the former owner of the 'Holos Fram' shown here, for allowing me to reproduce his images.