When the pair of kiers are filled, the manholes are closed, and high-pressure steam is blown for about a quarter of an hour through both kiers, the pipes connecting the kiers being shut off and the draw-off taps below open. This drives out the cold water and air, and heats the goods through, only a small quantity of lime water being lost. On closing the draw-off and steam taps, and opening the liquor tap of one of the kiers, the necessary 1400 galls. of boiling water are drawn in from the batch cistern. In about twenty minutes, all the water has entered, and the liquor tap is closed. High-pressure steam is now again admitted into this kier (the two-way tap of the other kier being suitably arranged previously, to connect the two kiers), and the liquor is driven through the goods, out by the bottom, up the connecting pipe, and on to the goods in the second kier. In about twenty to thirty minutes, all the liquor is in the second kier. Both two-way taps are now reversed, steam enters the second kier, and forces the liquor through the goods in the same way back on to the goods in the first kier. This alternating process is continued for about seven hours, boiling with steam at 40 to 50 lb. pressure; the steam is then turned off, the manholes are opened, and the liquor is run off below. The two ends of the pieces are at once found, since they are tied to a piece of string, the end of which passes through the manholes and is attached outside.
Washing.—The pieces are now washed direct from the kiers through the " lime-washing machine," and piled down on the floor.
Lime Sour or Grey Sour.—They are then run from pile through the "lime-souring machine," and piled again on the floor, to remain in this state for from one to two hours. The souring machine is fed from the cistern with a solution of hydrochloric acid, at 2° Tw. If con venient, the pieoes may be run direct from the lime boil, or " lime hawking," as it is often called, through the washing machine and at once through the souring machine without piling between. In this case, the two machines must run at exactly the same speed, and several yards of slack piece are allowed, before entering the souring machine, to drop on the floor, or pre ferably on to a, travelling apron or endless band of wooden spars, driven in connection with the machines.
Washing after Lime Sour.—In this washing, it is most essential that every trace of acid be 2 expelled from the cloth, hence the pieces are run from the pile through two washing machines successively, and direct into the kiers, to be boiled with resin soap.
Resin Boil or Ley Boil. First Boil in Resin Soap and Soda.—The pieces are admitted into the kiers exactly in the same way as for the lime boil. When the manhole lids are screwed on, steam is introduced to drive off air and cold water, and to heat up the cloth as before. The liquor tap of one kier is opened, and resin-soap liquor, equal to 770 lb. soda ash, 214 lb. resin, and 1400 galLs. boiling water, is run in from the batch cistern. The quantity of cloth in the two kiers is supposed
to be 12,000 lb. The kiers are worked by driving the liquor from one to the other, as before, for seven hours, with steam at 40 to 50 lb. pressure. The steam is turned off and the liquor is run out, its expulsion being aided. by turoing steam on again. When all the liquor is out, the steam and draw-off taps are closed, and the liquor tap is opened, to admit soda-ash liquor.
Second Boil in Soda Ash alone.—Soda-ash solution, equal to 120 lb. soda ash, and 1400 galls. water are run in from the batch cistern, and the boiling is continued, as before, for one or two hours. The steam is then shut off, the liquor is run out, and the manholes are opened.
Washing after Ley Boils.—The pieces-are now run direct out of the kiers through the washing machine iuto pile. It is usual to pile the goods on a wooden stillage, to keep them clean.
Chemielring.—They are then passed through the " chemickiug machine," which iS fed from the chemick cistern with a clear solution of bleaching powder at i° to i° Tw., and are run into pile, in which state they remain two or three hours, or even over night. If convenient, the pieces may be run direct from the ley boil, through the washing and chemicking machines, without piling between.
White Sour.—The cloth is next run through the " white-souring machine," fed from the cistern with a solution of sulphuric acid at 2° Tw., and are again piled for two or three hours.
Final Washing.—The pieces are now washed thoroughly in the final washing machine, and are either piled on a wooden stillage, or, if convenient, are run direct through the squeezers, to be at once opened and dried.
It will now be well to inquire into the theory of tho modern bleaching process as described above, and to notice slight modifications of details as practised in different bleach-houses, drawing attention, at the same time, to important points which must be remembered to ensure success.
Notes on Grey Washing.—Some bleachers omit the first washing, and run the dry greys at once through the limeing machine into the lder. Though not absolutely essential, this first washing is most advisable, especially where the liming machine is small. Its principal object is to prepare the cloth for absorbing the milk of lime more evenly by making it thoroughly damp ; at the same time, it removes some of the size and filling. Formerly, it was customary to steep the greys in a pit of cold water for two days or so and then to wash, hefore limeing, in order to ensure regularity in the lime boil ; but this slow process has been gradually discontinued, and is not now usually practised. In this " rot-steeping," as it was called, the starchy matters of the size were rendered soluble by the fermentation which took place, and were thus easily washed out ; there was, however, always the danger of " tendering " the cloth in this process, by the fermentation becoraing too vigorous and attacking even the cotton fibre itself.