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 the laws of three-color mixture. Extant data on these relationships are due to Maxwell, Abney , and König and Dieterici , the results obtained by the first investigator, however, being at present of relatively little value. The remaining two investigations were made with quite different light sources and choices of reference points, but are capable of being reduced to a common denominator by appropriate calculations. This work has been carried out very painstakingly by Mr. E. A. Weaver of the present Committee, who finds that the two sets of data actually agree surprisingly closely, so that they may legitimately be averaged. The results, reduced to an equal energy spectrum and referred to average noon sunlight as an origin (in trilinear coördinates) are given in and.



. Elementary Color Excitations for Different Wave Lengths

(The ordinates correspond with the values listed under “Excitations” in .)

A detailed account of the method employed in the reduction of the two sets of data will be given in a separate publication, but may be outlined briefly here as follows. Abney’s luminosity curve values were first converted so as to refer to average noon sunligh