dye remains in the vat.  By this time the coolies have had a rest and food, and now they return to the works, and either lift up the mall in earthen jars and take it to the mall tank, or—­as is now more commonly done—­they run it along a channel to the tank, and then wash out and clean the vat to be ready for the renewed beating on the morrow.  When all the mall has been collected in the mall tank, it is next pumped up into the straining room.  It is here strained through successive layers of wire gauze and cloth, till, free from dirt, sand and impurity, it is run into the large iron boilers, to be subjected to the next process.  This is the boiling.  This operation usually takes two or three hours, after which it is run off along narrow channels, till it reaches the straining-table.  It is a very important part of the manufacture, and has to be carefully done.  The straining-table is an oblong shallow wooden frame, in the shape of a trough, but all composed of open woodwork.  It is covered by a large straining-sheet, on which the mall settles; while the waste water trickles through and is carried away by a drain.  When the mall has stood on the table all night, it is next morning lifted up by scoops and buckets and put into the presses.  These are square boxes of iron or wood, with perforated sides and bottom and a removeable perforated lid.  The insides of the boxes are lined with press cloths, and when filled these cloths are carefully folded over the mall, which is now of the consistence of starch; and a heavy beam, worked on two upright three-inch screws, is let down on the lid of the press.  A long lever is now put on the screws, and the nut worked slowly round.  The pressure is enormous, and all the water remaining in the mall is pressed through the cloth and perforations in the press-box till nothing but the pure indigo remains behind.

The presses are now opened, and a square slab of dark moist indigo, about three or three and a half inches thick, is carried off on the bottom of the press (the top and sides having been removed), and carefully placed on the cutting frame.  This frame corresponds in size to the bottom of the press, and is grooved in lines somewhat after the manner of a chess-board.  A stiff iron rod with a brass wire attached is put through the groove under the slab, the wire is brought over the slab, and the rod being pulled smartly through brings the wire with it, cutting the indigo much in the same way as you would cut a bar of soap.  When all the slab has been cut into bars, the wire and rod are next put into the grooves at right angles to the bars and again pulled through, thus dividing the bars into cubical cakes.  Each cake is then stamped with the factory mark and number, and all are noted down in the books.  They are then taken to the drying house; this is a large airy building, with strong shelves of bamboo reaching to the roof, and having narrow passages between the tiers of shelves.