CHAPTER XII 

 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. 



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 un- 

 satisfactory, since the least jar may disturb it, and inserting the 

 plateholder 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 } inch thick, 1J inches wide, 

 and 5 feet long, so as to form a guideway for the camera (Fig. 25, A). 

 If the camera is so small that it must be raised to bring it into the 



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