Crescent Dissecting Microscope. 
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No. 3020. 
The design and construction of this instrument have been specially considered with a view 
to perfect rigidity. Many dissecting microscopes are made on the lines of an ordinary micro- 
scope stand, that is with a small base and pillar and a stage with the addition of hand rests. Such 
a construction is unsuitable for dissecting as the weight of the hands upon the hand rests has a tend- 
ency to upset the instrument. In the Crescent dissecting microscope the base is a heavy casting 
on three projecting feet and with two uprights to support the hand rests and stage. The sup- 
ports are directly under the hand rests, so that weight and pressure upon them have no tendency 
to tip the instrument. A pillar is provided at the back within which fits a solid rod which carries 
a swinging arm for the lenses. This rod is focussed up and down by a rack and pinion actuated by 
a milled head, which is placed at a convenient angle for the hand. The amount of motion is over 
3 in. so that material of considerable thickness can be accommodated. The hand rests are of hard 
wood and the stage is a thick plate of glass. A mirror is provided below the stage, silvered on one 
side and opal glass on the other. 
The instrument is supplied with a single swinging arm for holding the lenses or with a double 
arm which gives greater latitude to the movement of the magnifier over the stage plate. 
No. 3020. Stand only ... bt seg sah ao ce ee nae oe S2e ie eG 
No. 3020A. Stand, with 2 single lenses x 5 and x 10 he ae: a ee 3 6 6 
No. 3020B. Stand, with 1 single lens x 5, and 2 achromatic lenses x 12 and x 20 Dee leo 
No. 3020C. Stand with 3 achromatic lenses, x 5, x 12 and x 20 a Te ay ilisy (8 
No. 3021. Double jointed arm fitted to any of the above ... i Peet 012 6 
No. 3022. Case for above £ e aa os oa a a as O17 6 
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