same colors on green; and Fig. 398 shows the different effects produced by printing the same colors on bine. Fig. 399 shows the changes which apparently take place in red, when it is surrounded by different colors; when surrounded by blue it appears tinged with orange; when surrounded by gray it appears at its true value; when surrounded by black it appears a little lighter than it is, and when surrounded by white it appears a little deeper than it is in fact; when surrounded by green it appears more brilliant than in either of the cases just mentioned. It appears most brilliant when surrounded by sea-green, its complement. Fig. 400 shows the changes which apparently take place in black, when it is surrounded by different colors; when surrounded by bine it appears slightly tinged with orange; when surrounded by gray it is seen at its real strength; when surrounded by red it appears slightly tinged with sea-green; when surrounded by white it appears darker than it is in fact; when surrounded by green it appears to be tinged with red-purple, the complement of green. 'The eyes must be held about twenty inches above the page while testing the explanations just given, to obtain the best result.
Plate 88.—This plate shows a combination of black and deep vermilion. By reading the matter on this plate it will be seen that no further explanation is necessary.
Plate 89.—The borders at top and bottom of this plate were printed in yellow, green and bine blended into one another—a good example of the harmony of relative colors—by gradation. The type form was printed in color No. 34, which is one of the darkest tones of red.
Plate 90.—This plate shows a specimen of map work printed in black and three tints. The tints were made by mixing the colors with magnesia, and were printed over the black. Magnesia makes a transparent tint which is specially suitable for work of this character. The black was printed first; then the blue
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