The sulphide of potassium (liver of sulphur) appears in fragments of a liver-brown mass which readily dissolves in water. The solution must be filtered before being filled into bottles for sale, and, as it becomes turbid in the air, kept in well-closed vessels. When the two solutions are brought together, black sulphide of silver results and darkens the hair. After the use of this preparation a disagreeable odor of rotten eggs adheres to the hair, but can be easily removed by washing, especially with one of the previously mentioned hair washes. The silver hair dye will be still better if the liquid contained in bottle II. is made by dropping into the solution, under continual stirring, ammonia water, until the precipitate first formed is again dissolved. MELANOGÈNE. I. (_In Dark Bottle._) Silver nitrate 150 grains. Distilled water 2¾ oz. Ammonia water 1 oz. II. (_In White Bottle._) Pyrogallic acid 15 grains. Alcohol of 40% 1 pint. TANNIN HAIR DYE. I. (_In White Bottle._) Powdered nut-galls 14 oz. Water 1 pint. Rose water 1 pint. Boil the nut-galls in the water, strain the boiling liquid through a thick cloth into the rose water, and fill the still hot mixture into bottles which must be immediately closed. (It is essential that the liquid be hot during the filling, to guard against the development of mould.) II. (_In Dark Bottle._) Silver nitrate 5½ oz. Distilled water 1 qt. Add ammonia water to the silver solution until the precipitate first formed is again dissolved. EAU D’AFRIQUE. I. (_In Dark Bottle._) Silver nitrate 45 grains. Distilled water 3½ oz. II. (_In White Bottle._) Sulphide of sodium 120 grains. Distilled water 3½ oz. CRINOCHROM. I. (_In White Bottle._) Pyrogallic acid 150 grains. Distilled water 6¼ oz. Alcohol 5¾ oz. II. (_In Dark Bottle._) Silver nitrate 180 grains. Ammonia water 2 oz. Distilled water 10½ oz. COPPER HAIR DYE. I. (_In White Bottle._) Ferrocyanide of potassium 7 oz. Distilled water 1 qt. II. (_In Dark Bottle._) Sulphate of copper 7 oz. Distilled water 1 qt. Add ammonia water to the copper solution until the light blue precipitate first formed again dissolves to a rich, dark blue liquid. This hair dye gives a dark brown color. EAU DE FONTAINE DE JOUVENCE, also called Auricome and Golden Hair Water, is no dye, but a bleaching agent which changes dark hair to a light blond or golden-yellow color. The preparation consists of peroxide of hydrogen, a substance possessing marked bleaching properties.