382 



BLEACHING 



and ready for the market If the cloth is wanted for printing, no further operation is 

 needed ; but if to bo sold as white calico, it is finished by being starched and 

 calendered. 



The starch at large works is prepared by the bleachers themselves. At Messrs. 

 Bridson's it is made with the very greatest care from flour. Of course it would bo 

 more expensive for them to buy it, as the manufacturer would dry it, and they would 

 require to dissolve it. They are able also, in this manner, to obtain the purest starch. 

 This is mixed with blue, according to the finish of the goods. A roller, which dips 

 into the starch, lays it regularly and evenly on the cloth in the same manner as 

 mordants are communicated in calico-printing, whilst other rollers expel the excess of 

 the starch. The cloth is then dried over warm cylinders, or by passing into a heated 

 apartment. It receives the final finish generally by the calender ; but muslins receive 

 a peculiar treatment. 



Calender. Fig. 131 is a cross-section of this machine, anil figs. 130, 132, are front 

 views broken off. The goods are first rolled upon the wooden cylinder a, near the 



130 



131 



ground ; by the tension-roller, b, upon the same cylinder, the goods receive a proper 

 degree of stretching in the winding-off. They then pass over the spreading-bars, 

 c c c, by which they are still more distended ; next round the hollow iron cylinder, d, 

 16 inches diameter, and the paper cylinder, c, of like dimensions ; thence they proceed 

 under the second massive iron cylinder, /, of 8 inches diameter, to be finally wound 

 about the projecting wooden roller, g. This is set in motion by the pulleys h ( Jiff. 132), 

 and i (Jiff. 131), and receives its proper tension from the hanging roller k; I is a 

 pressing cylinder of 14 inches' diameter, made of plane-tree wood. By its means we 

 can at all times secure an equal degree of pressure, which would be hardly possible 

 did the weighted lever press immediately upon two points of the calender-rollers. 

 The compression exercised by the cylinders may be increased at pleasure by the bent 

 lever, m, weights being applied to it at n. The upper branch of the lever, o, is made 

 fast, by screws and bolts at p, to the upper press-cylinder. The junction-leg, g, is 

 attached to the intermediate piece, r, by left- and right-handed screws, so that ac- 

 cording as that piece is turned round to the right or the left, the pressure of the 

 weighted roller will be either increased or diminished. By turning it still more, the 

 piece will get detached, the whole pressure will be removed, and the press-roller may 

 be taken off, which is the main object of this mechanism. 



The unequable movement of the cylinders is produced by the wheels s, t, u, of which 

 the undermost has 69, the uppermost 20, and the carrier-wheel, t, either 33, 32, 

 or 20 teeth, according to the difference of speed required. The carrier-wheel is bolted 

 on atw, and adjusted in its proper place by means of a slot. To the Tindennost iron 

 cylinder, the first motion is communicated by any power, for which purpose either a 

 rigger (driving pulley) is applied to its shaft at w, or a crank motion, If it be desired 



