_Colouring the Paper._--The pulp is brought to any desired tint by the addition of mineral pigments or aniline dyes to the contents of the engine. The latter soluble dyes, however, are seldom used for high-class rag papers. Prussian blue, ultramarine, and smalts are chiefly used for this purpose, giving toned blue, azure, and blue laid papers. [Illustration: FIG. 14.--The Hand Mould showing Frame and Deckle.] _Making the Paper._--The beaten pulp, when duly prepared, is run from the engine into store tanks known as stuff chests, ready for the actual manufacture. The pulp properly diluted with water is strained through special screens to remove any insufficiently beaten material and any impurities present, after which it is run off into the vat, a square-shaped vessel built of wood or stone. The apparatus used in forming the sheets is called a _hand mould_. The mould is a rectangular frame of mahogany upon which is stretched tightly a fine wire cloth, the surface of the latter being kept flat by a coarser wire cloth fixed underneath, supplemented by wedge-shaped pieces of wood. A second frame called the _deckle_ fits on to the mould in such a manner as to form a shallow tray, the bottom of which is the fine wire cloth. The vatman takes up the mould with both hands and dips it into the vat full of pulp in a slanting position, drawing it through the stuff towards him in a peculiar manner and lifting it out from the vat with a definite quantity of the mixture in the frame. As the water drains away from the pulp, through the wire cloth, he imparts a shaking motion to the mould in order to cause the fibres to "felt" properly, this felting or interlacing of the fibres being an essential feature in the manufacture of a good sheet of paper. When the water has drained away sufficiently from the pulp, the vatman removes the deckle from the mould and passes the latter over to the coucher, who takes the mould, reverses it, and presses the contents, which may now be described as a wet sheet of paper, down on to a damp piece of felt, by which means the paper is transferred to the felt. He returns the mould to the vatman, who meanwhile has made another sheet with a duplicate mould, and then, having laid a second felt upon the wet sheet of paper, he proceeds to transfer the next sheet of paper to the second felt. This process is continued until a pile is formed consisting of wet sheets of paper alternated with pieces of felt. The pile is at once submitted to great pressure in the hydraulic press, and the excess water slowly forced out, while at the same time the sheets are compressed and thus "closed up," as it is termed. When all the excess water has been removed as far as possible, the pile is taken away and the sheets of damp paper taken out, the felts being placed in one pile ready for further use, and the sheets of paper in a second ready for the next process.