is required on a great variety of subjects, this instrument will function for transmitted light, dark 
ground illumination, metallurgical work or the examination of all opaque objects or the study of 
opaque ores with polarised light. With a small prism over the vertica] tube it can be used for 
microprojection. The vertical tube will also receive a camera lucida for drawing. 
BRIEF SPECIFICATION OF THE INSTRUMENT. 
Bodies. 1. Binocular, with adjustments for interocular distance. 
2. Monocular body with graduated drawtube. 
3. Monocular body with drawtube, combined with a vertical tube and detachable 
camera (1 plate 44 in. x 34 in.) with exposing shutter. The vertical tube is 
provided with a focussing adjustment to set the focus on the plate to correspond 
with the visual focus. With camera removed it can be used for drawing or 
projection. 
Fine adjustment actuated on both sides of the limb, provided with divided drum. 
Coarse adjustment, helical rack and pinion with clamp for tightening or fixing position. 
Stages. Five alternative forms :— 
1. Plain stage with detachable mech- 
anical stage No. 3305 as illustrated on 
page 84. 
2. Built-in mechanical stage in which 
the large square top plate is moved in 
both directions instead of the object 
being moved over the surface of the stage, 
enabling large objects or culture plates 
to be moved mechanically as readily as 
3x1 slides. The front of this stage is cut 
away for the rapid interchange of the sub- 
stage apparatus, as illustration page 40. 
3. Mechanical stage as above, but not 
cut away in front. 
4. Mechanical stage No. 3515 as de- 
scribed on page 84 having horizontal 
travel of 3 inches and vertical travel of 
1} inches (as illustrated). 
5. Circular revolving stage with centring 
adjustments, plain, or with mechanical 
motions (No. 3306 page 84). 
Substages. Three alternative forms :— 
1. Rack and pinion focussing with Ake- 
hurst slides for interchanging apparatus 
(as illustration). 
2. Rack and pinion focussing and cen- 
tring, with standard size cylindrical 
fitting applicable to stages Nos. 1 or 4. 
3. Rack and pinion focussing and cen- 
tring, with addition of a swing-out motion 
with standard size cylindrical fitting, 
applicable to stages Nos. 1 or 4. 
Mirror. Plane one side, concave the other, on 
gimbals. Mirrors can be supplied with 
special plating for fluorescent work. 
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