PHOTOMICROGRAPHS AND LANTERN SLIDES 
151 
With so many condensers, the heat may damage preparations: 
so place between the last-named condenser and the one next the 
light a cooler filled with water or a solution of alum. 
With all these accessories, an additional iris diaphragm is desir¬ 
able. Place it between the middle one of the three condensers and 
the miscroscope, but quite close to the middle condenser. To make 
an efficient adjustment of all these parts requires patience, practice, 
and judgment. 
It will save time and patience if the position of the object to be 
photographed be marked in ink on the slide by vertical and horizontal 
lines, or by a circle around it. Even with these lines, it is none 
too easy to get the object into the desired position on the ground 
glass. Remove the ground glass and let the image fall on a piece 
of white cardboard a short distance back of the camera. If the 
curtains are pulled down, the position of the object in the field and 
the focusing of the condensers will be comparatively easy. 
The desirability of a rigid, straight, and accurate optical bed 
will soon be realized. If one is intending to do much photomicro¬ 
graphic work, the heavy, graduated optical bed is almost a necessity. 
However, if time is no object and patience is abundant, good photo¬ 
micrographs at a magnification of over 1,000 diameters can be made 
with no apparatus except a good camera, a good microscope, and a 
good lamp. 
The relative positions of the various parts, as we have used them 
in making the illustrations for this book, are indicated below: 
Tb 
73 
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a 
03 
& 
03 
03 
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Some data which may be helpful will be found in the legends under 
some of the photomicrographs. 
Easily available and inexpensive help will be found in three 
booklets published by the Eastman Kodak Company, of Rochester, 
New York: “ Photomicrography”; “ Wratten Light Filters ”; “ The 
Photography of Colored Objects. ,, 
