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iX, — An Improved Vertical Illuminator. 

 By Edwaed M. Nelson. 



(Jicad May 15, 1907.) 



The accompanying figures, which need hardly any explanation, show 

 an improved form of vertical illumination. The nose-piece (fig. 49), 

 which is cylindrical, contains a 45 degree plane glass mirror, which 

 is fixed and large enough to reflect a full beam passing through the 



Fig. 49 . 



hole, ^ in. in diameter, in the nose-piece. The strip of holes (fig. 50) 

 is a drawing, in plan, of a tube, which fits over the narrow part of 

 the nose-piece, and which is capable of rotation. The square 

 aperture is ^ in., and the circular holes are -^q in., ^q in., and 



Fig. 50. 



^ in. in diameter. The distances of the centres of the large and 

 small circular holes from the edges of the square hole are f-^ in. 

 and -j^o in., respectively ; and the centre of the intermediate sized 

 hole is ^ in from the others ; therefore the circumference of the 

 tube, which is ^^ i^^- thick, is 3 inches, outside measure, so it fits 



