1912.] Trichromic Vision and Anomalous Trichromatism. 167 



Strongly objected to the normal equation ; said that the mixed colour was orange, and 

 the simple, yellow. 



NageVs Test and Stilling 's Test. — Passed both these tests with much greater ease' and 

 more rapidly than most normal-sighted persons. 

 My Lantern Test. — -Passed easily. 



The above tests were made in the presence of Prof. Starling and Dr. Horaans. 

 Spectrometer. — 



Region of greatest luminosity X589-X605 



„ pure yellow X 591-X 596-5 



My yellow region X 583-X 590 appeared greenish-yellow to him. This region inclines 

 to orange-yellow to me. 



Pure blue was X 472-X 476. Pure green, X 510-X 51 4. 



Simultaneous contrast was not more marked than normal. Saw red below X 780. 

 The following are the monochromatic regions marked out by him : — 



■pp. 



j X7 j° | Called by him Red. 



„ Orange. 



X6261 



2. 1 / 



X 613-51 



3. 1 J 

 X 605 \ 



4. 1 J 



X5971 



5. 1 J 



X590\ 



6. 1 J 



X579\ 



7. 1 / 

 X567\ 



8. 1 / 



X558\ 



9. 1 J 

 X5411 



10. 1 J 



X523\ 



11. 1 J 



X516\ 



12. 1 J 



X509\ 



13. 1 J 



15. 1 / 

 Orange-yellow. ^ X491| 

 X 483-5 



MM- 



^ ^ 5 ^ j- Called by him Green-blue. 

 X4971 



Yellow. 

 Greenish yellow 



Yellow-green. 



Green. 

 Blue-green, 

 j) 



Green-blue. 



83-5 \ 



17. 1 J 



X4751 



18. 1 J 



X 466 5 1 



19. 1 J 



X457 \ 



20. 1 J 

 X4471 



21. 1 J 



X435\ 



22. 1 J 



X426\ 



23. 1 / 



X417\ 



24. 1 J 



X411 \ 



25. 1 J 



X407 



Blue. 



Deep blue. 

 Violet-blue. 

 Blue-violet. 

 >» 



Violet. 



It will be noticed that the region regarded by the normal-sighted as orange-yellow is 

 named and seen by him as greenish yellow. This gives an explanation of the anomalous 

 trichromatism. If the region to be matched appears greener than usual, it will obviously 

 require more green and less red in the mixed colour. 



These were the results of single observations ; the available time would not admit of 

 more and they clearly confirm the other tests. 



