150 The Mlcroscope. 



TECHNOLOGY. 



PHOTO-MICROSCOPIC STEREOGRAPHS. 



4 4 '' I HERE are innumerable bodies in the world of small things," 

 -*- says the Br. Jour, of Photo., " which can only be properly 

 observed, so as to realize their configuration, by a binoclar micro- 

 scope; and in the case of such objects, no matter how much they 

 may be enlarged by photography in the usual way or with what 

 perfection their detail may be rendered, they still afford a very inad- 

 equate idea of their form." 



Our object at present is to point out, briefly, some methods by 

 which the possessor of an ordinary monocular microscope may be 

 enabled to photograph any suitable object with all the relief as seen 

 in the finest binocular instruments, and this, too, without incuiTing 

 much expenditure for costly appliances. Premising that the method 

 to be described is intended for employment with low powers, we 

 shall explain its principle of action by a simile we employed many 

 years since, when we had occasion to introduce it to the notice of 

 our readers of those days. Let a bust or a statuette be placed on 

 a table at a distance of a few feet from a single, fixed camera, and 

 a negative be taken. Now, without moving the camera, rotate the 

 statuette on its axis in the slightest degree and then take a second 

 negative. Prints from these two negatives will, when mounted side 

 by side on a stereoscopic card- mount, and examined in a stereoscope, 

 show the image in all the solidity that could be desired, the amount 

 of relief being determined by the extent to which the original object 

 was x'otated previous to the second negative being taken. Reason- 

 ing from analogy, we now proceed to apply this system to the pro- 

 duction of micro -stereographs. 



The object-slide must not be placed flat down directly on the 

 stage of the microscope, but upon a secondary or superstage so con- 

 structed as to allow of the small platform upon which rests the 

 object-slide to oscillate from right to left within a limited sphere. 

 The one we constructed for the purpose is made of thin brass piv- 

 oted at its two sides into guiding side pieces, the axis of motion 

 being adjusted so as to coincide with the object to be photographed. 

 Having focussed the object and using a diaphragm in front of the 

 objective so as to increase its penetration, the first photograph is 

 taken, when the little, see-saw slide holder is tilted to one side, 

 after which it is tilted to the opposite side preparatory to making a 



