This drawing eye-piece is similar in construction to that
just described, but is so arranged as to throw the image
vertically downwards behind the microscope when the latter is
inclined at an angle of 45 degrees. In this case also the picture
reflected is clear and sharp, devoid of all disturbing secondary
images. As the image is reflected vertically downwards upon the
table, no special drawing stand is necessary as there is no
distortion of the picture. The intensity of the light may be
modified by smoked glass plates mounted in two moveable metal arms
$10.—
For a description of these drawing eye-pieces and of the principles involved in their construction reference may be had to the Zeitschrift für wissenschaftliche Mikroskopie, XII, 1895.
Abbe's Drawing Apparatus.
No. 94.
In Abbe's Drawing Apparatus the drawing field is reflected by
a mirror at the side of the instrument and by a prism which fits
over the eye-piece of the microscope. The prism is supported on a
vertical hinge so that it may be readily turned out of the axis
of the microscope without disconnecting the whole apparatus from
the stand. It is shown turned to the side in the figure. A
cylindrical cap accompanies the apparatus which fits over the
prism holder and has six lateral windows in which are smoked
glasses of various intensity, serving to regulate the lightness
of the reflected drawing field
$12.—
Drawing Board No. 95. Drawing Board after Giesenhagen.
The Drawing boards serve two purposes. They afford a smooth plane surface for the drawing paper and they are so arranged that they may be inclined at such an angle as to receive the rays of the reflected image at right angle to their surface, thus doing away with any distortion of the image on the paper.
No. 95.
This drawing board is especially adapted for use with drawing
eye-piece No. 92. When in the position indicated in the figure
its drawing surface forms an angle of 12° to the horizontal
$2.—
No. 96.
In Giesenhagen's drawing board the drawing surface may be
adjusted at various angles and may be raised and lowered
