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tween these letters. Surrounded by blue, the C appears to be a yellow-gray; surrounded by red it appears to be a green-gray; surrounded by black it is a pure gray, but appears much, lighter than it is in fact. The apparent change which takes place in a color, when it is surrounded by another color, is due to the fact that any color occupying a small area of surface will be strongly tinted with the complement of the color which surrounds it.

Plates 69 to 79, inclusive.—These plates represent a series of impressions showing a landscape printed in ten colors. Bach block is shown separate and also as registered into its proper place as the work progresses toward completion. The picture represents a scene in the Pyrenees Mountains, in Southern France, and was reproduced from an old picture printed in the early part of this century. Fig. 376, on Plate 79, is the completed picture; the last impression was the border, or mat, which was printed in a green-gray, and then the whole picture was embossed, or roughed, with an electrotype taken from a sheet of emery paper.

Plate 80.—The borders at top and bottom of this plate were printed in rose-lake and three of its light tones—making a fine example of the harmony of scale—by gradation of tone; then the back-ground of the page was printed in an olive tint from an engraved plate; then the type form was printed in olive—the whole producing a most pleasing and harmonious page.

Plate 81.—Fig. 378 on this plate shows an impression from an electrotype taken from emery paper. Fig. 379 shows an impression in a deep blue-black from a plate engraved with bunches of needles fastened together.

Plate 82.—Fig. 380 shows an impression in a deep photo- brown from a piece of walnut wood, side grain. Fig. 381 shows an impression in the same color, from a piece of ash wood, side grain.

Plate 83.—Fig. 382 shows an impression from a piece of quartered oak wood. Fig. 383 shows an impression from a piece

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