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bulletin: museum of comparative zoology. 



r'fp'h was duplicated on the opposite side in r"f"'p". When the 

 lateral glowers /' and /" were swung into the center, the three formed 

 a compact prismatic combination, which generated the powerful 

 illumination necessary for the blue-violet and green. A cross-section 



Fig. C. Front perspective view of lamp, a, wooden base; 6, arch of brass; 

 c, mercury cup; e, copper plug; /, /', /", Nernst glowers; h, wooden column; m, 

 pivoting point ; n, screw; p, p', p", posts; r, r', r", arms; s, adjusting screw. 



of this combination is represented in the plan of the apparatus. Fig. A, 

 by the triangle of three dots at /. For yellow only / and/' were needed, 

 while the single, central glower was sufficient for red. In the latter 

 two cases the unused glowers were swung out of the field to avoid 

 the disturbing reflections from them. 



