342 SIE W. DE W. ABNEY : MODIFIED APPAEATUS FOE MEASUEEMENT OF COLOUE 

 with green and violet to form the white, and - gives us the amount of violet. 



4*7 



Take, as an example, SSN (42) : 



ES. ES. GS. GS. 



54'9-40-la; = (447-59'92a;) 2'265. 



From this we get 



, 54-9-40-1 x -484 - 



x = '484 and = '726, 



49 



the amount of violet present in SSN 42. 



The scale numbers in Tables I. and II. were thus treated and the violet as shown 

 in Table III. was so obtained. 



(18.) Colour Sensation* in SSN (37'5). 



The amount of white light in (37 - 5) has already been determined as 69 per cent. 

 It only remains to add this amount of white to the green in the standard equation 

 and equate it when so altered to the standard equation. 



When the luminosity of the GS is increased by 69 per cent, the equation becomes 



ES. (37-5.) V. W. ES. GS. V. 



40'91-f 58'27 + '84 = 100, the standard equation being 68'4 + 30'2 + r4 = 100. 



These give us the composition of 



(37-5.) RS. GS. V. 



100 = 47-19 + 5T85+-96. 



(14.) Determination of SSN's from 36 to 12. 



The method described above was adopted to determine the SSN's 36 to 12. The 

 following is an example : 



(54.) (34-9.) W. 



53'4 + 46-6 = 100 (j.), 



(54.) ES. GS. 



But 100 = 90-5 + 9-5 (ii.). 



From (ii.), (i.) becomes 



RS. GS. (34-9.) W. 

 48-33 + 5-08 + 46-6 = 100. 



Equating with the standard equation we get 



(34-9.) ES. GS. V. 

 100 = 43-07 + 53-93 + 3U 



