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Aug. 1922]
Colorimetry Report 1920-21
549

instead of to the carbon arc (as given), using Watson’s data[1] for the energy distribution of the latter and Abbot’s (1) data on that of the former (vide infra), The corresponding luminosity and percentage color excitation values were then combined as products to yield excitation values referred to sunlight, rendering them

Table 6

Spectral Colors in Terms of Elementary Excitations
Wave-
length
Excitations Percentages Wave-
length
Excitations Percentages
Red Green Violet Red Violet Red Green Vio-
let
Red Violet
400 . . . . . . 253 . . . 100 550 424 612 18 40 .2 1 .7
410 . . . . . . 433 . . . 100 560 466 578 11 44 .2 1 .0
420 . . . . . . 614 . . . 100 570 505 517 7 49 .5 .7
430 . . . . . . 915 . . . 100 580 520 415 4 55 .4 .4
440 . . . 7 1019 . . . 99 .3 590 535 296 . . . 64 .3 . . .
450 . . . 16 950 . . . 98 .3 600 510 196 . . . 72 .2 . . .
460 . . . 38 842 . . . 95 .7 610 462 113 . . . 80 .4 . . .
470 . . . 81 697 . . . 89 .6 620 375 59 . . . 86 .3 . . .
480 14 122 473 2 .3 77 .6 630 285 29 . . . 90 .8 . . .
490 41 169 220 9 .5 51 .1 640 195 10 . . . 95 .1 . . .
500 83 260 123 17 .8 26 .4 650 118 3 . . . 97 .5 . . .
510 151 391 87 24 .0 13 .8 660 68 . . . . . . 100 . . .
520 233 510 61 29 .0 7 .6 670 40 . . . . . . 100 . . .
530 307 572 43 33 .3 4 .7 680 22 . . . . . . 100 . . .
540 373 603 29 37 .1 2 .9 690-
750
27 . . . . . . 100 . . .

These values are for an equal energy spectrum. The relative magnitudes of the three elementary excitations have been chosen so that the curves for average noon sunlight have equal areas; that is, if the percentage values are plotted on a trilinear diagram, sunlight falls in the center. The absolute excitation values are based upon a convenient arbitrary unit. The percentage values are given for the red and violet only since those for the green can be found by subtracting the sum of the other two values from 100 in each case.

comparable in this respect with the values given by König and Dieterici. The respective trilinear representations of both sets of values then coincided, except for the positions of the elementary “green” excitations and the sides of the two triangles joining the green and the “violet” elementaries. Although the relation between

the two green elementaries could not be determined directly, it
  1. See (5, p. 96, Table 1 and p. 97, Fig. 3).