with the gray. The gray colors are quite generally termed "broken colors" and this seems a very useful practice, "because it avoids the confusion of the somewhat similar terms "gray color" and "colored gray."
By reference to the Chart of Broken Spectrum Scales on Page 41 it will be seen that we have only twelve scales and but three tones in each scale, instead of eighteen scales and five tones, as in the pure scales, for which there is a good reason.
For educational purposes in the elementary grades, which is the only place where there is a legitimate use for colored papers, the steps in gradation of hue or tone must not be too short, and if the saturation or intensity of the normal colors in the several scales is reduced by adding gray, as in the broken colors, there is not the possibility for as many steps in either hues or tones without leaving those colors adjacent to each other too nearly alike. Therefore in the broken colors there are but thirty-six, instead of ninety, as in the pure scales.
The distinction between pure colors with tints and shades, and broken colors in various tones, should be made very plain to the children whenever the subject is brought to their notice, because it is a vital point in the classification of colors. Educationally this is one of the most objectionable features in the old red, yellow and blue theory of color composition, because no distinction is observed between pure and broken colors in classification. In the Bradley colored papers the distinction is made very decided for educational purposes, so that no one would for a moment tolerate the mixture of the normal colors from the pure scales with the normal colors from the broken scales in the formation of a spectrum.
This may be illustrated by a selection as follows: First lay in order the normal spectrum colors with the pure colors found in the first section of the sample book, thereby forming the central vertical column of Fig. 10. Then substitute for the orange, green and violet, those colors selected from the collection of broken colors, and the result will seem to render the
