THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XIY. DECEMBER, 1893. No./ 



Stereoscopic Photomicrography. 



Bv DR. \V. C. BORDEN, U. S. ARMY 



NKWPOBT, R. I. 



WITH FB0NTI8PIECK. 



StereoHcopic photomicrographs are sueprior to ordinary photo- 

 micrographs for representing some microscopic objects. Their 

 advantages are the representation of real form through the 

 effect of relief, and the ability to present and combine into 

 one image more than one focal plane of the object photographed. 



It has been considered one of the disadvantages of a photo- 

 micrograph as compared with a drawing, that while the latter 

 may be constructed so as to represent an object as it appears to 

 the observer while successively viewed at different focal planes, 

 the former pictures one focal plane only. It has been suggested 

 that by a succession of exposures upon the same plate with the 

 objective focussed differently for each exposure, a composite 

 photograph could be built up which would represent the object 

 with tlie truthfulness of photography and the pliability of draw- 

 ing. This method, though widely exploited, fails utterly in 

 practice; for a succession of sharp impressions of different planes 

 of an object when superimposed produces no perfect image and 

 gives only that appearance so familiarly known throughexam- 

 ples of composite photography. 



But b\' means of stereoscopic photomicrography the two 

 most important planes of an object may be superimposed and 

 combined so that a picture of the object having at the same 

 time natural relief and sharpness is produced. To obtain this 

 result the two negatives necessary for the stereoscopic picture 

 are taken with reference to the production of stereoscopic effect 

 and a different focus is tcsed for each exposure. 



