The green shell of the walnut fruit and the root are used for dyeing brown. The husks to be used for dyeing must be collected green and fresh, then covered with water and kept from the light to prevent them oxidizing. In the walnut tree there is an astringent colourless substance which gives a greenish yellow dye. This has the property of absorbing oxygen from the air and turning dark brown. It is only the unoxidized pale greenish stuff that can act as the dye, the dark brown itself has no affinity for the wool. Acids should be added to the dye bath to prevent oxidization. Without a mordant the colour is quite fast, but if the wool is mordanted with alum a brighter and richer colour is got. When used they are boiled in water for 1/4 hour, then the wool is entered and boiled till the colour is obtained. Long boiling is not good as it makes the wool harsh. It is much used as a "saddening" agent; that is, for darkening other colours. "The best and most enduring blacks were done with this simple dye stuff, the goods being first dyed in the indigo or woad vat till they were a very dark blue, and then browned into black by means of the walnut root."--_William Morris._ PEAT SOOT gives a good shade of brown to wool. Boil the wool for 1 to 2 hours with peat soot. Careful washing is required in several changes of water. It is used sometimes for producing a hazel colour, after the wool has been dyed with weld and madder. OAK BARK. Mordant with alum and dye in a decoction of oak bark. ONION SKINS. (Brown.) Mordant the wool with alum. Drying two or three times in between makes the colour more durable. Dry. Wash. Boil a quantity of onion skins, and cool; then put in wool and boil lightly for 1/2 an hour to 1 hour; then keep warm for a while. Wring out and wash. BLACK. Mordant with 3% Bichromate of Potash for 45 minutes. Dye with 1 oz. Hematin crystals, 3/4 oz. madder, 1/2 oz. Persian berries. After boiling for 1 hour remove wool and add 1/4 oz. cream of tartar, 1 oz. cochineal, 3/4 oz. iron, 1/2 oz. copper sulphate. Return wool and boil again for 1/2 hour. Wash in soap. VARIOUS RECIPES MADDER for BROWN. (1 lb. wool.) Mordant with 1 oz. copperas and 1 oz. cream of tartar. Dye with 6 ozs. madder. MADDER, etc., for FRENCH BROWN. Mordant with 3 per cent chrome. Dye with 8 per cent fustic, 2 per cent madder, 1 per cent cudbear, 2 per cent tartar. If not dark enough add 1 per cent logwood. Boil for 1/2 hour. Wash and dry. TAN SHADE. (6-1/2 lbs. wool.) Mordant with 3 ozs. Chrome for 45 minutes and wash in cold water. Boil for 1/2 hour in a bag 5 oz. madder, 4 oz. Fustic, 1/2 oz. logwood. Enter the wool, raise to the boil, and boil for 45 minutes. By altering the proportions of madder and fustic various shades of brown can be got. GREENISH BLACK. (For 1 lb.) Mordant with 3 per cent Chrome. Dye with 2 ozs. Fustic, 2 ozs. logwood, 1 oz. madder, and 1 oz. copperas.