Stuffing the dressing leathers is carried out in a variety of ways and with a variety of materials. The old process of hand stuffing employs a mixture of tallow and cod oil called "dubbin." This is made by melting the ingredients together and allowing them to cool with constant stirring to a nearly homogeneous salve. The dubbin is brushed thickly on to the flesh side of the sammed leather, which is then hung up to dry. As the moisture dries out the oils and soft fats penetrate the leather and leave the more solid fats on the outside. The proportions of tallow and oil are varied with the time of year and with the method of drying, for if the dubbin be too soft it will run off the leather, and if too hard will not penetrate it so well. Drum stuffing is a more modern development in which a higher temperature is employed, about 140° F. The drum is heated up by steam or by hot air, and the sammed goods are then inserted and drummed for a few minutes until they are warmed. The drum is fitted with a heated funnel containing the melted grease, which is run in through the hollow axle. After a half to three-quarters of an hour's drumming the grease is completely absorbed by the leather. The drumming is continued for a while until the goods have cooled. Whilst still warm they are "set out" to remove creases and superfluous grease. Drum stuffing is not only quicker than hand stuffing, but also makes it possible to use the hard fats, and so make a leather which carries more grease without appearing greasy. Thus in drum stuffing, paraffin wax and wool fat are used, and their penetration assisted by small proportions of cod oil or dégras. If the leather be too wet the grease is not absorbed, whilst if it be drier than usual the leather will take more grease, but the resulting colour is not so good. There is also another method of stuffing which originates from the Continent. It is known as "burning in" and involves the use of still higher temperatures (195° to 212° F.). Wet leather will, of course, not stand this temperature, so that it is first necessary to make the leather absolutely dry. This is effected by drying in stoves at temperatures up to 110°-115° F. There are two ways in which the grease is applied. In one method the melted grease is poured by a ladle on to the flesh side and brushed over until evenly distributed. A second application of grease is made to the thicker parts. The hides are then put into warm water (120° F.) for about a quarter of an hour, and then drummed for half an hour. In the other method the goods are completely immersed in the melted fats for a few minutes in a steam-jacketer tank at a temperature of 195° F. After softening in water at 120° F. the goods are drummed. "Burning in" is used for the heavier dressing leathers such as belting and harness. It does not give good colour, but permits the employment of still more hard fats. REFERENCES. Procter, "Principles of Leather Manufacture," pp. 223, 378.