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CHAPTER VIII.

PRINTING.

T>EFORE proceeding to give a systematic description of the various stylesof printing, a brief account will be required of the two principalmachines used in modern print-works,—the perrotine and the cylinder machine.The former of these executes a style of work very similar to hand-blockprinting. Three wooden blocks, from 2 \ to 3 feet in length, according to thewidth of the pieces, and varying in breadth from 2 to 5 inches, have thepattern engraved in relief on their surface. They are fixed, with their faces atlight angles to each other, in a stout iron frame, and can each in turn bebrought down upon the front, top, and back, of a four-sided iron prism, facedwith cloth, and revolving upon an axis. The goods to be printed pass betweenthe prism and the pattern-blocks, and receive the impressions in succession.The blocks are forced down upon the calico by means of springs, so as toimitate the pressure of the hand of the block-printer. After each impressionthe block takes up a fresh coat of colour, by contact with a surface of flannel,upon which the mixture is kept continually applied by means of a self-a&ingbrush. The perrotine is shown in section in Fig. 24, and in elevation inFig. 25, both these illustrations being taken from the “ Traite de l’lmpressiondes Tissus ” of Persoz.

a, cast-iron frame, bbb, cast-iron tables, planed smooth, over which passthe blanket, the back-cloth, and the calico to be printed, c c c, sliding pieces,on which are screwed the block-holders, 3, causing the pattern-blocks, 2, tomove in turn against the layer of flannel and the pieces to be printed, bymeans of the play of the levers 4 and 5, whose supports, 6, rest upon a, anda&, by means of coupling-rods, upon the beams, 7, keyed to the slides c. Thelower of these sliding-pieces is vertical, and takes by its own weight a retro-grade movement, regulated by a counter-weight, eee are movable colour-sieves, fixed to coupling-rods, and receiving a suitable movement from thepower which works the machine. The sieves are flat, and covered with clothon the face opposite to the block. They work in grooves on the sides of thetables, and receive from the furnishing rollers the colours, which they thenpass on to the pattern-blocks, fff are colour-troughs, filled with the colourmixture, and fitted each with two rollers', 8 and 10. The latter dips into thetrough, takes up colour, and transfers it to 8, which is covered with woollencloth, and which it carries on to the sieves, e, where it is spread by thebrushes, g. In order to regulate the amount of colour supplied to the sieves,and thence to the blocks, the rollers, 10, are fitted with levers, 11, which, by