From information mainly gained by Mr. G. H. Pepper, of the American Museum of Natural History, during his three years' sojourn with the Navahoes as head of the Hyde Exploring Expedition, I present the following accounts of their native dyes. From the earliest days the Navahoes have been expert dyers, their colors being black, brick-red, russet, blue, yellow, and a greenish-yellow akin to the shade known as old gold. To make the black dye three ingredients are used; viz., yellow ochre, pinion gum, and the leaves and twigs of the aromatic sumac (_Rhus aromatica_). The ochre is pulverized and roasted until it becomes a light brown, when it is removed from the fire and mixed with an equal amount of pinion gum. This mixture is then placed on the fire, and as the roasting continues it first becomes mushy, then drier and darker, until nothing but a fine black powder is left. In the meantime the sumac leaves and twigs are being boiled, five or six hours being required to fully extract the juices. When both are somewhat cooled they are mixed, and almost immediately a rich bluish-black fluid is formed. For yellow dye the tops of a flowering weed (_Bigelovia graveolens_) are boiled for several hours until the liquid assumes a deep yellow color. As soon as the dyer deems the extraction of the color juices nearly complete, she takes some native alum (_almogen_) and heats it over the fire, and, when it becomes pasty, gradually adds it to the boiling decoction, which slowly becomes of the required yellow color. The brick-red dye is extracted from the bark and roots of the sumac, and ground black alder bark, with the ashes of the juniper as a mordant. She now immerses the wool and allows it to remain in the dye from half an hour to an hour.