Radial Research Microscope. 
The Radial microscope in its complete form (No. 3190) is a universal instrument for 
research. The general design is that of a small optical bench, which is swung in a concentric 
fitting, so arranged that as the instrument is changed from the vertical to the inclined or horizon- 
tal position, the centre of rotation is in the optic axis, and the centre of gravity always lies 
near the centre of the base. This arrangement combined with the focussing stage which the 
instrument possesses, is of special importance for metallurgical work where a vertical illuminator 
is used, as the illumination, once having been set, is not altered by the inclination of the instru- 
ment or by the focussing. : 
The instrument has a heavy base with two uprights in which the limb swings in grooves. The 
limb has a parallel dovetailed slide provided with a rack along its entire length, and all the parts 
of the microscope fit this dovetail and are moved upon it, and with the exception of the mirror 
slide, are actuated by racks, pinions and milled heads. Upon the upper part of this slide is fitted 
the body of the microscope with its fine adjustment. In a position near the middle is fitted the 
stage and substage which are in one unit. The lower end of the main slide carries the mirror. 
The rack and pinion actuating the body forms a coarse focussing adjustment. The body 
fitting also carries the nosepiece, which, actuated by a double lever action, forms the double 
speed fine adjustment, which is operated by two side milled heads each giving a different speed. 
The slow motion slide only carries the object glass and does not support the weight of the body, 
The body fitting has a square hole down its entire length, in which fits a bar. At the upper 
end of this bar is fitted a bracket to which a telescopic drawtube is attached. By means of a rack 
and pinion this drawtube can be raised for a distance of 25 in. Also by means of the telescopic 
tube it can be raised further giving a variation in tube length of from 110 to 250 m/m._ This bar 
and its drawtube can be completely removed and replaced by a high power binocular body. 
Apparatus such as a spectroscope or a small camera can be attached to this bar and drawtube. 
There is no fear of upsetting the fine adjustment by the attachment of these pieces of apparatus, 
as the fine adjustment mechanism works quite independently, these other pieces of apparatus 
being separately supported. 
A Greenough binocular can be supplied on a separate carriage which fits in the main dove- 
tail slide of the microscope. 
The stage slide consists of a focussing carriage, the upper portion of which carries the stage 
and the lower portion of which carries the substage. Two forms of stage are supplied: one is the 
square stage as fitted to the Massive microscope, and the other is the complete circular rotating 
stage with centring motion as described on page 84. The square stage is cut out in the 
front to enable the substage apparatus to be readily changed. The substage focusses by rack 
and pinion and has centring adjustment, and consists of a cylindrical fitting of the R.M.S. standard 
diameter. It also has a dovetailed slide similar to the system adopted in the Massive microscope, 
so that an achromatic condenser or a dark ground illuminator can be permanently centred upon its 
respective slide and can be interchanged without altering the position of the substage. 
The petrological apparatus is on the well known ‘‘ Dick”’ principle, by which the polariser and 
analyser are rotated together, the angular rotation being read on a scale on the analyser. The 
mechanism has been improved by the substitution of direct acting links for cog wheels, and also 
a great improvement has been made in working the fine adjustment independently of this apparatus, 
which in the older models, owing to its weight, put considerable strain upon the fine adjustment. 
A simpler form of Radial research microscope is also made (No. 3192). In this the 
body fitting has a different arrangement for the fine adjustment slide which carries the whole 
body. The arrangements for carrying the various interchangeable bodies is not provided and 
the petrological apparatus cannot be fitted. 
For full description of the Radial microscope and its use see ‘‘ The Microscope: an Advanced 
Handbook,” by Conrad Beck, price 7/6 net. 
33 
