ing most pleasing combinations. Consequently in the Bradley colored papers the tints are very light and the shades quite dark.
If, instead of adding either a white disk or a black disk to a spectrum color, by which we make pure tints and shades, we add both white and black, a line of gray colors or so-called broken colors is formed. This is most beautifully shown with the disks, and in this way a line of true broken colors is secured, because in each case a true neutral gray has been added to the color, which cannot be insured in the mixture of gray pigments. As an example, this may be shown with the three smaller sizes of the orange disks. With the medium size of these three make the combination Orange, 35; White, 10; Black 55. With the larger size disks make the proportions Orange, 16; White, 5; Black, 79, and with the smallest size Orange, 43; White, 33; Black, 24. Place these three sets of disks on the spindle at one time and you have the three tones of a broken orange scale.
With similar combinations applied to the six standards and one intermediate hue between each two, there will be material for a chart of Broken Spectrum Scales, as shown in Fig. 11, including twelve scales of three tones each. These are the most beautiful colors in art or nature when combined harmoniously. Because of the loss of color in broken colors it is not advisable to attempt so many different hues or so many tones of each hue as in pure colors, for slight differences in either hues or tones are not as readily perceived.
In these two charts of color scales two distinct classes of colors are represented, namely, pure colors and broken colors. The pure colors consist of the purest possible pigmentary imitations of spectrum colors, with their tints and shades, and the broken colors are these pure colors dulled by the admixture of neutral grays in various tones. This distinction is readily recognized under proper training, so that if a broken color is introduced into a combination of colors from a pure scale it will be readily detected, which always occurs when the attempt is made to produce a series of spectrum scales by the combina-
