With the single exception of Vanderpoel (Color Problems, p. 28, plates 3, 4, where yellow is given first in order of luminosity) all authorities on color-physics that I have been able to consult very singularly ignore yellow entirely in their treatment of the subject of luminosity. [26] All quotations here are from Milton Bradley's "Elementary Color," except where otherwise noted. [27] As determined by Dr. P. G. Nutting, Associate Physicist, U. S. Bureau of Standards. [28] See Rood, Modern Chromatics, pages 34, 35. [29] The aniline or coal-tar dyes named are all of the manufacture of Dr. G. Grübler and Co., Leipzig, Germany, unless otherwise stated. (See Preface, page ii.) CAUTION!!! DO NOT EXPOSE THESE PLATES TO THE LIGHT FOR A LONGER TIME THAN IS NECESSARY. The pigments used in the preparation of these Plates are the most durable known, those which have been proven unstable having been, as far as possible, discarded. The latter include carmine and other cochineal lakes, colors of vegetable origin (as gamboge, violet carmine, indigo, etc.), and most of the aniline or coal tar dyes, though among the last are a considerable number which are really more permanent than several colors habitually used by artists. Certain colors in this work could not, however, possibly be reproduced except by the employment of pigments which are more or less sensitive to _prolonged exposure_ to light, and hence this caution not to expose the plates unnecessarily. (See _Church_: "The Chemistry of Paints and Painting," third edition, pages 257-263.) _Plate I_ 1 RED 3 O-R. 5 OO-R. _f_ Hermosa Pink La France Pink Shrimp Pink _d_ Eosine Pink *Geranium Pink Strawberry Pink _b_ Begonia Rose Rose Doree Peach Red Spectrum Red Scarlet-Red *Scarlet _i_ *Carmine Nopal Red Brazil Red _k_ Ox-blood Red Garnet Brown Morocco Red _m_ Victoria Lake *Maroon *Claret Brown _Plate II_ 7 R-O. 9 OR-O. 11 ORANGE _f_ Safrano Pink Orient Pink Orange-Pink _d_ Grenadine Pink Bittersweet Pink Light Salmon-Orange _b_ Grenadine Bittersweet Orange Salmon-Orange Grenadine Red *Flame Scarlet *Orange Chrome _i_ English Red Mars Orange *Orange-Rufous _k_ Mahogany Red *Burnt Sienna Sanford's Brown _m_ *Bay *Chestnut Auburn _Plate III_ 13 OY-O. 15 Y-O. 17 O-Y.