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NOTE ON A SLIDING NOSE-PIECE FOR USE IN 

 STEREO-PHOTOMICROGRAPHY. 



By a. C. Banfield. 



{Rend June 2St?i, 1910) 



In October last I had the pleasure of reading a paper on low- 

 power stereo-photomicrography and also had on exhibition the 

 apparatus and a few examples of this class of work. 



To obtain the results shown then, the object was moved by an 

 amount determined by the magnification and which gave a truly 

 stereoscopic pair of images, at least as far as the object itself was 

 concerned. 



Later experiments in this direction with very low powers, and 

 with the object strongly lighted to throw sharp shadows, gave 

 some unpleasantly peculiar results : although the image of the 

 object was perfect, the shadow from it floated in space and gave 

 a, very irritating presentment of the whole. 



This defect was, of course, due to the altered incidence of the 

 light falling on the object, which is great with very low powers, 

 as the object has to be moved a considerable distance. It is 

 of course impossible to move the illuminating apparatus, conden- 

 sers and so forth, with the object ; the only thing we can do 

 in such a case is to move the objective. To obviate the necessity 

 of this I have had a little piece of apparatus made which fulfils its 

 purpose exceedingly well. It consists of a sliding plate screwed 

 to carry the objective and which is laterally displaceable by means 

 of a small rack and pinion. For several reasons this is more 

 convenient than moving the object, as the illumination is unaltered 

 and the shadows fall in their right place, greatly adding to the 

 beauty of the picture. 



