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CALICO-PRINTING 



By this contrivance the motion termed rocking is effected, that kind of motion being 

 required when the pattern repeats at great intervals. The mill works in bearings 

 attached to the pillar and carriage H H, which is moved from right to loft by the 

 screw 1 1 ; the mill is forcibly pressed against the copper roller by a weighted lever, 

 which forces down the bearings of the mill in the pillar H ; this lever cannot be shown 

 in the figure, but is at right angles to the roller. The mill being in contact with the 



copper roller, revolves with it simultaneously on the roller being moved by the 

 wheels D D or the lever E, and consequently impresses or engraves its pattern on the 

 copper roller ; when the mill has traversed the circumference, it is then moved to its 

 next relative position by the screw i, which moves the pillar and carriage H ; the 

 exact distance the mill moves is determined by an index on the wheel K, which is 

 divided into segments, corresponding with the number of repeats laterally on the 

 roller. The apparatus shown at L is used occasionally when the machine is employed 

 for turning off an engraved pattern, which, however, is generally performed in a slide 

 lathe, and is unnecessary further to describe here, 



Etching by nitric acid is largely employed in engraving for calico-printing. The 

 roller is coated all over with a thin film of bituminous varnish. Lines of any required 

 form or quantity are then traced upon it, which lay bare the copper surface beneath. 

 On immersion in a bath of diluted acid, those parts of the roller only which are ex- 

 posed become bitten or etched to any required depth, the remaining surface of the 

 roller being protected by the varnish. This process is employed in combination with 

 the mill process, for engraving all ' solids,' that is, those parts of an engraving which 

 are intended to contain masses of colour, to be transmitted to the calico in the 

 printing-machine. For this purpose the outline of the solid to be engraved is first put 

 on with the mill ; the roller is then varnished, and a number of diagonal or angled 

 parallel lines are traced upon it with a diamond-point. Those portions which are 

 intended to be white on the calico, are ' stopped out,' or covered with varnish, by the 

 operative, and the roller is ready for immersion in the bath of diluted acid. The 

 roller is removed when the requisite depth is obtained, is well washed and the 

 bituminous coating is removed, and after slight examination and addition by the 

 hand engraver is ready for the printer. But the two most notable applications of 

 etching in the trade of engravers to calico-printers have been the ' Eccentric ' and 

 ' Pontagraph ' systems. The former owed its greatest development to the late Mr. 

 Joseph Lockott, son of the founder of the eminent firm which still bears his name. 

 It is not essential to the scope of this article, to give an elaborate description of the 

 beautiful and ingenious machinery employed, nor would it be possible without a very 

 elaborate set of drawings. It may suffice to record that by means of diamond-points, 

 actuated by elaborate machinery, a most curious variety of configurations is 

 produced on the roller. In this process the exact effect that will be produced by any 

 given modification of the machine, cannot be determined beforehand, though an 

 approximation can be made ; but when a pattern is produced, and notes are taken of 

 the relative position of the wheels, &c., the same pattern can at any time be reproduced. 

 This system is applicable principally to ground-works or, as they are termed, ' covers,' 

 which form the bases of backgrounds of many classes of design much in vogue on 



