-----------+-----------------------+-----------+--------+-------- | | No. of | | | | Wave | | | | Lengths | | W.L.K. | Wave Length Position. | from |Division| per | | Colour | |Division | | between | | | | each. | | -----------+-----------------------+-----------+--------+-------- 760,400 A. |Red 760,400 | | | |-----------------------+ 72,717 | == 20 | 3,635 |Orange 687,683 | | | |-----------------------+ 72,716 | == 20 | 3,635 |Yellow 614,967 | | | |-----------------------+ 72,716 | == 20 | 3,635 |Green 542,251 | | | |-----------------------+ 72,716 | == 20 | 3,635 |Blue 469,535 | | | |-----------------------+ 72,716 | == 20 | 3,635 396,819 H. |Violet 396,819 | | | -----------+-----------------------+-----------+--------+-------- 363,581 |Total W.L. between A. & H. 363,581 | 100 | -----------+-----------------------------------+--------+-------- Having provided equal wave length positions for the six pure colours, the intermediate colours are necessarily binaries in definite proportions, accounted for by a regular overlapping of two bounding colours in opposite directions from zero to 20, as shown in the following table from Red to Orange, representing the space between these two pure colours. Red 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 W.L W.L 687, 760, 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 683 400 -------------------------------------------------------------- Orange. 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 ============================================================== It follows, that apart from the six monochromes, all spectrum complex colours in a single wave length must be binaries, whose united values equal 20. On comparing Professor Rood’s scales of divisions with those of the tintometrical scales already described, they appear to coincide in several particulars, for instance:-- The monochromes correspond both in number and in name. Their positions in the scales correspond. Their unit divisions are equal in number, and in dimensions. Their colour positions correspond, when an artificial tintometrical spectrum is made by regularly overlapping monochromes.