Among the accessories are three Watson objectives with canisters,
two eyepieces, an Abbe condenser with iris, and a triple objective changer. The Holos
Fram, introduced in 1902, is a more advanced instrument compared to the standard Fram Model. It has a full
mechanical stage and a substage with centering adjustments similar to what is found
with the Edinburgh Student Model H.
The following was extracted from the 1906 Watson Catalog:
W. Watson & Sons
"HOLOS" FRAM MICROSCOPE
The extensive demand for a Microscope having a first-class fixed mechanical
stage that will enable work to be performed with high powers, with precision,
and be thoroughly suited to laboratory requirements and especially for Bacteriology,
has caused us to introduce a special model of our well-known “Fram” Microscope
that combines these conveniences. In all general details it is identical with our
“Fram” Microscope, but has in addition:
1. A Mechanical Stage.
2. A Substage, with screws to centre and Rack work to focus.
The Mechanical. Stage.—This is generally the same in construction as
that fitted to our “H” Edinburgh Student’s Microscope (see page 48)
The four-thread screw by means of which the horizontal movement is imparted,
is controlled by a stationary milled head, and the vertical motion is effected
with a spiral rackwork and pinion. The range of movement in each direction is
about one inch. The size of the upper surface of this stage is 2 7/8 x 3 1/8 in.
Hitherto an attachable mechanical stage only has been supplied to fit the "Fram"
Microscope, and this being at all times greatly inferior in action to a fixed
one, the efficiency of the “Holos” Fram instrument will be vastly increased for
high-power work, with the new Mechanical Stage.
The Compound Substage.—The Substage is as figured on page 91, No. 450. It
is of full size and has rackwork to focus, screws to centre, and can be turned
aside with the apparatus contained in it so that direct illumination from the
mirror may be obtained when desired.
The Instrument can be recommended in the strongest terms as of the highest
efficiency. It is of best workmanship throughout. The price is the lowest
at which such a comprehensive instrument has ever been suppled.
