A G-eometric Slide Photo micrograpliic Apparatus. 



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For metallography the method adopted is to use the apparatus 

 in the horizontal position, and to mount over the vertical illumi- 

 nator attached to the Microscope a totally reflecting prism (fig. 4). 

 This prism is mounted high enough above the stage of the Micro- 

 scope, when the latter is horizontal, to receive a beam from the 



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Fig. 4. 



illuminant, and from any subsidiary condensers without obstruc- 

 tion. This arrangement I have myself used for many years, and 

 it appears to me to be more simple, and certainly involves less 

 alteration in any apparatus, than placing the illuminant at right 

 angles to the optic axis. All adjustments are quite as easily made, 

 and in this case also the proper illumination of the object can be 



