CHAPTER XIII 
PHOTOMICROGRAPHS AND LANTERN SLIDES 
While a work like the present book is hardly the place for any 
extended treatment of photomicrography or the making of lantern 
slides, a few simple directions will help the beginner and enable him 
to prepare most of the photomicrographs and lantern slides which 
may be necessary in the classroom. It is assumed that the student 
knows how to handle an ordinary camera and knows how to do his 
own developing. 
In the preparation of this chapter, I am indebted to Dr. Paul J. 
Sedgwick for suggestions, criticism, and considerable revision. 
PHOTOMICROGRAPHS 
For a simple beginning, no apparatus is needed except an ordi¬ 
nary camera and a microscope. Try low powers first and proceed 
gradually to the higher magnifications. Remove both front and 
back lenses from the camera, leaving the lens barrel and the shutter; 
also, remove the eyepiece from the microscope. Bend the micro¬ 
scope to the horizontal position and place the lens of the camera 
close to the ocular end of the microscope and shut out all light at 
this point by winding black cloth around the end of the microscope 
and the barrel of the camera lens. Take great care to have a per¬ 
fectly straight optical axis through the microscope and camera. 
While the camera and microscope can be adjusted so as to secure 
a perfect optical axis by simply putting both instruments on the table 
and raising one or the other—according to the size of the camera—• 
by placing a board under it, such an adjustment is extremely unsatis¬ 
factory, since the least jar may disturb it, and inserting the plate- 
holder is almost sure to disarrange something. It will save time 
if you prepare a board to keep both instruments in position. Select 
a clear board 1 inch thick, about 1 foot wide, and 5 feet long. On 
the top of this board, screw two pieces f inch thick, 1| inches wide, 
and 5 feet long, so as to form a guideway for the camera (Fig. 29 A). 
If the camera is so small that it must be raised to bring it into the 
145 
