Mictoscope Eyepieces. 
No. 3259. Comparator eyepiece a ae ae are a so SLOMIOMEO 
This eyepiece is for use with two microscopes, for giving in one eyepiece, the images in 
each microscope combined into one field of view for comparison purposes. 
No. 3273. Erecting eyepiece ... see a ue oe S35 oie One. 
This is a compound eyepiece for use > with ¢ a ‘16m/m (3 inch) object glass. With this object 
glass it gives a magnifying power 10 to 40 diameters by extending the drawtube and a very large 
field of view. It gives an erect instead of an inverted image and is particularly useful for dissecting. 
No. 3276A. Cobweb eyepiece micro- 
meter... ee a0 £9 707520 
This eyepiece has two cobwebs, one of 
which is fixed and the other is movable by a 
micrometer screw. The screw has a milli- 
metre pitch and a drum divided into 100 
parts, each division reading 1/100 millimetre. 
The saw-shaped scale of teeth is so 
arranged that each tooth is equal to one 
turn of the screw. 
No. 3276A 
No. 3275. Beck micrometer eyepiece ae ne so ie yO 
A» 
ae 
This consists of a complete eyepiece with a magnifying 
“a iy power xX 8, and aspecial vernier millimetre scale placed in its focus. Tale 
\ It is provided with a collar which fits over the drawtube 1 | | if 
and can be clamped in position by a milled head. The eyepiece = | 47 
has an adjustment for focussing the scale. allay rb 
The scale (see diagram) is in millimetres with a vernier reading ‘-) | | 74 
to 1/10th of a m/m. On the left is a vertical series of divisions j=)! 4-3 } 
divided in half millimetres for rough measurement. For fine =~ | | | ; 
in 
measurement the object to be measured is placed in a horizontal +3 71% 
position, and is measured to 1/10th m/m. by use of the slanting 
No. 3257 
line on the right. The image of an object as shown in the diagram measures 3-25 m/m., because 
it covers three large divisions and extends to the oblique line at a point halfway between the -2 
and -3 of tenth millimetre vernier divisions. 
To obtain the actual size of the object itself this result has merely to be divided by the initial 
magnifying power of the object glass. 
No. 3256. Ehrlich eyepiece - ; ge 833 1G) 
This is a Huyghenian eyepiece of standard sive and power x6 and provided with a square 
aperture, the size of which can be varied from 1 to 8 mm. _ It is useful for measurement of areas 
or for blood counting. 
75 
