Etch all shades of the color pretty deeply in any of the stippled or aquatint styles. After this, coat the stone with gum solution, that it shall take no color in these depressions. Clean off the chemical ink or the ground with oil of turpentine, and prepare the whole plate if it has not been prepared already on its surface. Then coat it with red gum surface, and into this inscribe all those lines that are to remain black. Then the color is rubbed-in and the stone cleansed so that it will be white everywhere except in the engraved parts. When it is inked-in now, it can take color there only, and the other depressions (namely the various shades of the color) will remain white because they have been prepared. Now it is necessary only to coat each part with the desired water color and it will be denser, and therefore darker, wherever there are more and greater depressions. II SIMULTANEOUS CHEMICAL AND MECHANICAL PRINTING When a pen drawing is so constituted that the various lines are close together and there is no white space on it that is greater than at most one half inch in diameter, it will permit printing in a purely mechanical way without being prepared. It need merely be etched into all the relief possible without under-eating the lines. All that is needed then is a color-board or a so-called dauber, made as follows:-- A thin board of soft wood, about eight inches long and six inches wide, is planed down till it is not more than one line in thickness. Glue on it a piece of fine cloth or felt almost as large as it. Over this glue another board, of the same area as the first, but one quarter inch thick. It must be very well-dried wood, and must be made very true with the plane, or better still, by rubbing on a perfectly level stone with sand. This latter board is provided with a handle; and when all is dry this dauber is ground off true again with fine sand and oil on a stone. Lay the printing-color on this utensil very gently and uniformly with a leather ball. Tap and pat the stone, which has first been cleaned with oil of turpentine over its whole surface, very carefully with the appliance, holding it as horizontal as possible and taking great pains to distribute the color evenly. As compared with chemical printing, this process in itself has no advantages, but can be united with it and thus used to print three colors from one plate. This is shown by the following EXAMPLE