CALICO-PRINTING 593 



account of their utility and variety. The Pentagraph system is of later development, 

 The process is the following : 



The pattern is first enlarged to several times its size : this is conveniently done by 

 the camera. The paper pattern being put in the camera, an enlarged copy is thrown 

 on a table in a darkened room, and is there easily traced on paper. It is then trans- 

 ferred to a thin zinc plate, and this plate is then engraved with a graver, the lines of 

 the engraving being adapted for the tracing-point to work easily in. The zinc 

 pattern, if of a 2- or more coloured pattern, is coloured for the guidance of the 

 operative. It is then laid on the bed or table of the pentagraph machine, and a var- 

 nished roller being mounted in the machine, a number of tools, corresponding in 

 number to the repeats laterally, and carrying diamond points, are placed in contact 

 with the roller. The operative then carries the tracer successively into all the lines 

 of the pattern, a lever allowing the points to touch the roller only when necessary. 

 The pattern is thus traced by the etching points on the roller a less size than that on 

 the zinc plate, or the same size as the paper drawing. The roller is then painted and 

 etched with nitric acid, as before described. In 1834 Horton Deverill of Manchester 

 patented the first application of the pentagraph principle to engraving cylindrical 

 surfaces for calico-printing. It was the simplest form of the ordinary pentagraph, 

 viz., a rhomboidal arrangement of levers, the relative adjustment of which, through 

 appropriate connections, secured the transfer to the roller of the design from its 

 enlarged copy. The time was not propitious for the adoption of this clever 

 invention ; a machine was tried by Mr. Lockett, and abandoned less on account of any 

 inherent defect, than because of the very limited use which could be made of it in 

 the then prevalent style of engraving. In 1848 Isaac Taylor patented the substitu- 

 tion for the single rhomboidal frame of Deverill's pentagraph, several such frames in a 

 continuous series. It was proposed to secure by this means a higher power of 

 diminution in a compact machine, and as a result, a more perfect engraving. He also 

 multiplied the number of bars supporting the tracing or etching tools. With this 

 machine commenced the first commercial application of the pentagraph system of 

 engraving in England, though on a very limited scale. In 1854 William Rigby 

 introduced and patented an improved machine, based on the American invention of 

 William Whipple. Whipple had constructed a machine with a curved bed for the 

 zinc plate instead of the flat tables of Deverill and Taylor. The tracing point was 

 attached to a swinging frame, and motion was communicated to the roller, and etching 

 tools respectively in a similar manner to that shown in Rigby's machine, figs, 335 and 

 336. In a patent dated January 1, 1857? Rigby applied two rows of etching tools to 

 his machine, whereby the time occupied in tracing the pattern was very considerably 

 diminished. This method was soon very extensively adopted: a reference to the 

 annexed figures will more clearly show the main features of this machine. 



In figs. 335 and 336, a represents the cylinder to be operated upon; and b, the bed 

 or table for the reception of the enlarged pattern or original device ; c, the tracer, which 

 is made to traverse in the direction of the arc of the bed or table, and by means of its 

 connection with the carriage h, the rail d, and the connecting arms e e, communicates 

 part of a revolution to the bar or axis /, and thence to the cylinder through the dies 

 ff g, on which the cylinder rests. The cylinder being thus moved in a rotatory direc- 

 tion, will receive from the tools in contact with it diminished copies of the transverse 

 lines which may have been gone over by the tracer on the enlarged pattern or device, 

 The tracer c being connected with the carriage h which travels along the rail d, will, 

 in passing over a line running longitudinally with the machine, communicate a partial 

 revolution to the wheel I by means of the bands of steel j j t similar to watch-springs, 

 which pass under and over the small wheels k k, and are passed round and secured to 

 the large wheel I, which is mounted on the vertical shaft m, carrying at its upper end 

 the small drum m', round which passes the steel band , secured at each end to the 

 pieces o o. These pieces are secured by bolts or screws to the sliding frames p, to 

 which the upper tool bar or bars q, which support the graving, drilling, or etching 

 tools r r r, are fixed. Thus any motion of the large wheel I will be imparted to the 

 drum m', and by it through the steel band to the sliding frames^ and the tool bars 

 q, and, consequently, to the tools r, thereby transferring to the cylinder diminished 

 copies of any lines in a lateral direction that may be gone over by the tracer. It will 

 be evident that the result of the simultaneous action or compounding of the two 

 motions, by passing the tracer over any diagonal or curved line, will be the pro- 

 duction of a diminished copy of such diagonal or curved line by each of the tools, s is 

 a treadle with a vertical link and appropriate leverage, by which the tools may be 

 brought in contact with the cylinder when required ; 1 1 are counterbalance weights 

 for the connecting arms e e, lower rail d, &c. ; u and v represent a worm and wheel 

 for the purpose of giving the roller an extra partial revolution when it is required to 

 engrave upon a different portion of the circumference of the cylinder ; and to effect a 



VOL. I. Q Q 



