CLOSE-UP STEREOGRAPHY 249Therefore, it is impossible to draw a sharp line between macro
and micro so far as size is concerned. We shall, for that reason,
consider the micro field to include all conditions in which the
combination of camera and compound microscope are used. It
may be added that with very few exceptions, the camera is the
normal, single, photomicrographic type and not a dual stereo
camera. This, of course, indicates the necessity for making suc-
cessive exposures a technique which is classic in stereomicro-THE MIcRoscoPE.-Photomicrography, and consequently stereo-
micrography, is hardly popular among amateurs. Probably the
reason is that the compound microscope must be mastered before
really good results can be obtained. The possibilities can be
shown when it is stated that among those who use the microscope
daily in their work, not one in one hundred has ever seen a really
well defined microscopic field. There is no instrument in common
use, not even the camera, which is so universally abused by its
users. The reason is not hard to find. Anyone can buy a camera,
shoot one roll of film and get results good enough to make vaca-
tion souvenirs; anyone can be shown how to focus a microscope
and be taught to handle it well enough to obtain passable results
in a few days, so why go further?
As a matter of fact, it takes months or years of practice before
one can use the camera with complete confidence and competence,
and it takes at least twice as long to learn correctly to manipulate
the compound microscope.
Among other elementary things, one must learn how to illumi-
nate, how to control the cone of illumination, how to set the tube
length, how to compensate adjustable objectives and how to focus
the condenser. If one is interested in making photographs, the
apochromatic objective is just as essential as is the anastigmat
upon a camera.
Volumes larger than this whole book have been written about
the correct manipulation of the microscope, and the ground has
not been fully covered. Obviously, we cannot be expected to cover
that ground in a single chapter. We must, therefore, fall back
upon purely stereoscopic technique, leaving the purely micro-
scopic and the purely photographic techniques to be learned from
other sources. We shall, then, assume that the reader has, or can
graphye