No. 3201 Massive Microscope. 
The Massive microscope was designed to provide an instrument for the use of research 
workers, which by reason of its great rigidity and accuracy of construction, would enable the full 
advantage to be taken of the latest forms of high power object glasses, achromatic condensers and 
dark ground illuminators, which have reached a very high standard, and which therefore require 
similar perfection in the mechanical adjustments of the microscope upon which they are used. 
This rigidity of construction allows for the interchange of the object glasses and substage appara- 
tus, without any danger of disturbing the adjustments, so that the change over from transmitted 
to dark ground illumination can be made rapidly and without incurring the necessity of any 
general readjustment of the microscope. The advantages of such an instrument, in the saving of 
time and in the high order of performance obtained will readily be appreciated. For such work as 
photo-micrography this great rigidity is also of the utmost benefit. 
The following is a brief description of the main constructional details. 
The limb consists of a massive brass casting which extends in one piece from the body to the 
mirror. The tail piece and slow motion slide are planed out in one continuous cut to ensure perfect 
alignment of the substage and focussing slides. The stage is rigidly fixed to side wings which form 
an integral portion of the limb. The base and pillar supporting the limb are heavy and so 
designed to render the instrument equally rigid in all positions. The back of the foot of the micro- 
scope carries a short vertical post to take the weight and form a rigid support when the 
microscope is in a horizontal position. 
The fine adjustment is exceptionally delicate; each division on the milled head moves the 
body -001 m/m. The coarse adjustment milled heads are very large, enabling an accurate setting to 
be made. 
The stage measures 44x43 inches. It is flat with a gap cut out in front to enable substage 
apparatus to be readily changed without altering the focussing adjustments. The mechanical stage, 
which fits into dovetails cut in the flat stage, has specially delicate motions actuated by milled heads 
which project from the right hand side. The cross slide has a travel of 3 inches and the vertical 
slide has a travel of 1} inches. Vernier scales are provided to both movements, and a clamp is 
attached to the vertical motion. 
The substage has rack and pinion focussing and centring adjustments and has a tubular fitting 
of the standard (Ik.M.S.) size. Its upper surface has an additional dovetailed fitting to receive 
apparatus. Substage condensers and dark ground illuminators are mounted in dovetailed fittings, 
held in position by a clamping milled head. These are accurately centred and are of the 
same height so that they can be rapidly changed while the object is under observation, the gap in 
the front of the stage permitting this to be done without the focus of the substage being altered. 
The tubular portion of the substage is free to receive other apparatus which can be used in con- 
junction with condensers and illuminators. 
The body is of 2 inch diameter, with a drawtube giving a variation in length from 140 m/m. 
to 200 m/m. A rack and pinion double extension drawtube, as illustrated on page 30 can be 
fitted if desired. A high power binocular eyepiece can also be fitted to the instrument. 
The microscope is packed into a solid mahogany cabinet. 
In many laboratories employing a large number of microscopes, a small proportion of the 
equipment consists of Massive microscopes which are used for the most exacting work. 
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