G24 



CALICO-PRINTING 



tion of the 'ageing machine,' which leaves the printed pieces in such a condition, that 

 a few hours is sufficient to perform the work formerly occupying days, and hence a 

 notable economy of space and time. In a patent of Mr. John Thorn in 1849, for 

 sulphuring mousseline-de-laines, a claim is made for using the same apparatus, or n 

 modification of it, for passing calico printed goods through a mixture of air and 

 acqueous vapour. Mr. Thorn found that a printed piece as it came from the machine, 

 absorbed nearly an ounce of moisture to the pound of cloth, without feeling damper ; 

 and that an exposure to a moist atmosphere for one minute and a half was sufficient 

 to produce this result. The ageing machiuo introduced by Mr. Thorn into the Mayfield 

 Printworks, had a capacity of 30 cubic yards. The moisture was obtained by having 

 a cistern of water kept heated to 180 1<\ in the machine. Mr. Crum was the next 

 printer to take this idea and work it into more practical shape, by very much extending 

 the size of the machine, and by other minor alterations. The use of this machine 

 rapidly spread, and is now almost universal. Fig. 372 shows the machine as arranged 

 by Mather and Platt. It consists of a chamber about 36 feet long, 20 feet high, and 

 13 feet broad ; generally it is partitioned off one of the disused ageing rooms. A, is 

 the framing forming the machine and for carrying rollers, &c. ; B, rollers 9 inches 

 diameter for drawing the cloth, these are driven by gearing ; c, rollers of tin plate, 

 not driven ; D, entering rollers and rails ; E, plaiter for folding cloth on delivery from 



372 







the machine ; F, steam or vapour pipes, with steam taps antl funnels for spreading 

 the vapour ; o, the cloth passing through the machine. The machine is enclosed in 

 a wooden room, the boards or walls fitting close at the ends H and o ; space being 

 left on each side for passage and for getting to the rollers, taps, &c. ; one or two 

 Daniell's hygrometers are put in different places of the machine. Two pieces, side by 

 side, are run through at once, the temperature being 70 to 75 F., and sufficient 

 steam being allowed to escape into the machine to cause a difference of 4 on the 

 hygrometers. The pieces occupy about 20 minutes during their passage through the 

 machine ; on emerging from which, they are plaited down into loose bundles of several 

 pieces, which are then drawn away and left on the floor of the room all night. The 

 temperature and hygrometic condition of this outside room should be as near as 

 possible those of the ageing machine. What takes place in ageing in this manner 

 has not been fully investigated ; but it is probable that as the piece leaves the printing 

 machine, the mordant is almost altogether on the surface of the fibre in an unaltered 

 state, that the thorough permeation of the piece by the aqueous vapour dissolved 

 in the air, restores to the cloth the normal water removed by the drying in the hot- 

 room, and that under the influence of this, and the slightly elevated temperature, first, 

 a separation of mordant from the thickening substance takes place, and the solution 

 diffused through the fibre, and secondly, that the fibre now begins to play the part of 

 an acid of superior affinity for the base of the mordant to the volatile acetic solvent, 

 and gradually withdraws it from the mordant, acetic acid being freely given off, 

 evident enough to the eyes and nose on going inside the machine. The change once 

 begun is more slowly carried on in the outside room, but still with much more rapidity 

 than under the former conditions of agoing rooms. The chemical action of cellulose 



