THE STEREOSCOPE 59The slightest possible motion is enough. One fourth a millimeter
displacement will produce well defined stereo relief. The use of
the typewriter maintains both type alignment and degree of stereo
relief, so there is no sign of the irregular relief seen in hand-
lettered messages.
When such cryptograms are printed in type, the characters are
separated by “thin spaces,” and for the second impression the ap-
propriate spaces are withdrawn, thus shifting the position of the
WHATEVER WORDS
YOU WRITE YOU
MUST STAND BY
YOUR STATE.
MENTS WI TH OUT
CEASI NO THERE’
IN YOU WILL
CON FRONT YOUR
OPPONENTS WHO
OFFER THE1 R
OBJECT1 ONS TO
EACH SENTENCE
YOU COMMIT TO
PAPER
Fig. 3-18. RegularWHATEVER WORDS
YOU WRITE YOU
MUST STAND BY
YOUR STATE.
MENTS WI THOUT
CEASl NO THERE.
IN YOU WILL
CONFRONT YOUR
OPPONENTS WHO
OFFER THE1 R
OBJECT1 ONS TO
EACH SENTENCE
YOU COMMIT TO
PAPER
spaced cryptogram.character. If ordinary 24 pound paper is used for spacing, the
difference in the two imprints will not be obvious to the unaided
eye, but the stereoscope will reveal a decided relief.
These are but a few suggestions as to the ways in which the
stereoscope may be used by the interested stereographer. But in
any experimental work, one thing must be kept in mind; in fact it
must be kept in mind at all times. The stereoscope and the stereo-
gram must, independently and jointly, be in perfect adjustment.
This means a rigid, accurate stereoscope, preferably of metal con-
struction with lenses correctly aligned, and if it is of the lenticular
type the interpupillary must be correctly adjusted. The stereo-
gram must be exactly aligned along the base, the homologous
separation must be that correct for the stereoscope used and pref-
erably matched to the interpupillary of the spectator, although
this is hardly practical when more than one person is to view it.
The stereogram should be set at the infinity focus of the instru-
ment, and the viewer should have lenses accurately matched in
focal length to those of the camera. When such conditions are ob-
served, even the experienced stereographer will find new pleasure
in the complete realism of the subject revealed.