I (lis 



Journal of Applied Microscopy 



LABORATORY PHOTOGRAPHY. 



Devoted to Methods and Apparatus for Converting an Object into an Illustration. 



PHOTOMICROGRAPHY. 



III. Illuminating the Object. 



Before any photograph is attempted the optical parts shown in Fig. I (see cut, 

 page 15'25, Journal or Applied Microscopy, November, 1901) must be cen- 

 tered. These parts are the condensers, the diaphragms, and the microscope. 

 They are sufficiently centered if circular cardboards cut from dark pasteboard 

 and pierced with a pin hole in the center, and fitted into each one of them, per- 



(;nlgi brain cell of the lirst type, from the liippocam;) oi .[ i .u : llie small black lines of the dendrons and neuraxon 



woidd be drowned by too large a diaphragm and doubled by one too small. 'I'he figure was made with a 



Id mm. apochromatic f>biective and a camera extension of forty-seven inches without eyepiece, .x 70. 



mit a ray of light to pass through all to the center of the cross on the ground 

 glass. These cardboards can be kept, and the centering can be quickly tested 

 from time to time. 



The light and condensers, including the Abbe, should be so arranged that the 

 image of the source of light coincides with the object to be photographed, if a 

 10 mm. objective or one of higher power is to be used. If a thin paper is placed 

 under the clips on top of a slide, the image can be seen ; perhaps a surer way is 



