Colouring of wool, silk and other protein-base fibrous materials

Claim 1

A METHOD OF COOLING A WOOLLEN MATERIAL, WHICH COMPRISES SUBJECTING THE MATERIAL TO THE ACTION OF A HOT, AQUEOUS FIRST BATH CONTAINING FROM 2-12% BY WEIGHT, BASED ON SAID MATERIAL, OF AN INORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF SULPHURIC ACID AND HYDROCHLORIC ACID, AND FROM 0.5-8% BY WEIGHT, BASED ON SAID MATERIAL, OF AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF AMINO-NAPHTHOL MONO-SULPHONIC ACIDS AND AMINO-NAPHTHOL DI-SULPHONIC ACIDS, SUBJECTING THE TREATED MATERIAL TO THE ACTION OF A COLD, AQUEOUS SECOND BATH CONTAINING FROM 0.5-3% BY WEIGHT, BASED ON SAID MATERIAL, OF SODIUM NITRITE, AND THEREAFTER DEVELOPING A SUBSTANTIALLY PERMANENT COLOR ON THE WOOLLEN MATERIAL BY HEATING SAID MATERIAL IN A THIRD BATH CONTAINING A COLORED INORGANIC SALT SELECTED FROM THE GROUP CONSISTING OF THE CHLORIDES OF NICKEL, COPPER AND COBALT, THE SULPHATES OF NICKEL, COPPER AND COBALT, AND POTASSIUM BICHROMATE, AT A TEMPERATURE BELOW 85*C. UNTIL THE DESIRED COLOR APPEARS.