The first three operations above described, _viz._, pasting, graining out, and boiling on strength, are proceeded with; the clear boiling by means of a closed steam coil is continued until the "head" is boiled out and the soap is free from froth. A sample taken and cooled should be hard. Boiling is then stopped, and, after covering, the pan is allowed to rest for eight to ten hours, when the soap is ready for filling into frames, where it is crutched until perfectly smooth. _Curd mottled_ is usually made from melted kitchen stuff and bone grease. Its preparation is substantially the same as for curd soap, but the clear boiling is not carried so far. The art of curd mottled soap-making lies in the boiling. If boiled too long the mottling will not form properly, and, on the other hand, insufficient boiling will cause the soap to contain an excess of entangled lye. Having boiled it to its correct concentration the pan is allowed to rest about two hours, after which the soap is ready for framing, which should be done expeditiously and the frames covered up. Some lye, containing the impurities from the fats used, remains in the interstices of the curd, unable to sink, and as the soap cools it is enclosed and forms the mottling. The mottling may, therefore, be considered as a crystallisation of the soap, in which the impurity forms the colour. _Blue and Grey Mottled Soaps._--These are silicated or liquored soaps in which the natural mottling, due to the impure materials used in the early days of soap-making, is imitated by artificial mottling, and are, consequently, entirely different to curd mottled soaps. The materials employed in making mottled soap comprise bleached palm oil, tallow, bone fat, cocoa-nut oil, palm-kernel oil, cotton-seed oil, and, in some instances, rosin. The choice of a charge will naturally depend upon the cost; the property of absorbing a large amount of liquor, which is characteristic of soaps made from cocoa-nut oil and palm-kernel oil, is taken advantage of, as are also the physical properties of the various fats and oils, with a view to the crystallisation of the resultant soap and the development of the mottle. The fat is saponified, grained and boiled on strength, as previously described. After withdrawing the half-spent lye, the soap is just closed by boiling with water, and is then ready for the silicate or other saline additions.