works have been observed among other tribes, both nomadic and sedentary, and the observers have designated them as "sand-paintings," "sand-altars," etc. They are drawn in all the great rites, and even in some of the lesser rites—those of only one day's duration—small but handsome dry-paintings are sometimes made. They vary in size from four to twelve feet in diameter. Sometimes the fire in the centre of the medicine-lodge must be removed in order to accommodate them. The groundwork is sand, which is conveyed in blankets into the medicine-lodge, and spread out over the floor to the depth of about three inches. It is smoothed with the broad oaken battens used in weaving.
99. Before the sand is brought in, the pigments are ground to powder and put on broad pieces of pine bark, which serve as trays—or palettes, shall we say? The pigments are five in number,—white, red, yellow, black, and gray. The white, red, and yellow are made of sandstone. The black is made of powdered charcoal, with which a little sandstone is mixed to facilitate the grinding and give weight to the powder. The gray, made of black and white mixed in suitable proportions, is intended to represent blue, is called blue by the Navahoes, and, combined with the other colors, has the effect of blue in the paintings. It will be spoken of as blue in the subsequent descriptions. The Navahoes use indigo and a native bluish mineral pigment to paint masks, kethawns, and other small objects; but for the dry-paintings such a large quantity is needed that these would be too expensive. To apply the colored powder, a pinch of it is taken up between the thumb and first two fingers and allowed to fall slowly on the sand, while the thumb is moved over the fingers.
100. To paint one of these large pictures may require the labor of several men—a dozen sometimes—working from early morning till late in the afternoon. The picture must be finished before dark, for it is impracticable to work on it with such artificial lights as the Indians can command. While the work is in progress the priest who conducts the ceremonies does little more than direct and criticise. The operators have received a certain initiation. They have seen the picture painted before and are familiar with its details. If an error is made the faulty part is not erased; sand is spread on it to obliterate it, and the corrected drawing is made on the new deposit of sand. The pictures are drawn according to exact and established rules. Some parts are measured by palms and spans, and not a line of the sacred designs may be varied in them. In drawing straight lines the colored powder is poured over a tightened cord. But in a few cases the artist is allowed to indulge his fancy, thus, in drawing the embroidered pouches which the gods