270 CAPTAIN W. DE W. ABNEY ON THE COLOUR 



It was found in forming the equations to match white that 



W R 288-5 V 



100 = 47-06 + 5179 + T15. 



Also 



W R 270 V 



100 = 39-30 + 59-15 + T55. 



From which equation we find that 



270 R 288 -5 -V 



22-4 = 2-94 + 19-46. 



R 270' R R 288-5 V 



77-6 + 22-4 = 77-6 + 2'94 + 19'46. 



that is in (2). 

 Or 



RS GS 



(3) 100 (Or) = 80-54 + 19-46. 



Similarly it was found from slits placed at 205 and 283 that 



RS GS 



(4) 100 (Or) = 80-50 + 19'50. 



Other determinations gave a mean of 



RS GS 



(5) 100 (Or) = 80-50 + 19'50. 



The (Or) has SSN ('236), therefore 



(236) RS GS 



100 = 80-50 + 19-50. 



(XV.) Determination of the General Provisional Equation for White. 



Now the complementary colour to the violet at SSN 390 is SSN 245, and it was 



found that 



236 RS 245 



100 = 35-86 + 64-14. 

 But 



236 RS GS 



100 = 80-50 + 19-50. 

 Therefore 



245 RS GS 



(6) 100 = 69-60 + 30-40. 



