From the suspenders, the butts are transferred to the "handlers," where they are laid flat in the liquor. They are usually pulled over by hooks, which are very apt to scratch the grain. Sometimes strings are used, attached to the corners and held in notches or on pegs at the edge of the pit. Other tanners place a frame below the pack, with ropes at the four corners, by which it is raised sufficiently for the men to grasp the top butts with their hands. This is only practicable in pits of ample size. In American yards, the handling is almost universally performed by tying the sides with strings or fastening them in a long band by drawing the slit tail of one side through a hole in the nose of the next, and inserting a wooden "key." The string of the sides is then wound from one pit to another over a skeleton reel ([Fig. 41]). This method is also used in the lime-yard, and is frequently employed in England to handle offal, but it is not well adapted for butts. [Fig. 42] shows the application of mechanical power in a Chicago yard for the same purpose, by means of Ewart's drive-chain, which is manufactured in this country by Ley's Malleable Castings Co., at Derby, to whom I am indebted for the block.
Fig. 41.
The handlers are generally worked in sets, to each of which a fresh liquor is daily run, and the most forward pack is pulled over into it, and is often also dusted down with a little fine bark or myrabolans. The second pack follows into the liquor out of which the first has been taken; the third into that of the second, and so on. Frequently the greenest packs are handled up a second time in the course of the day, and put down again in the same liquor. The strength of liquors, and the length of time for which butts are retained in the handlers, are varied; but a time of 1-2 months, and liquors of 20°-35° Bark. are usual. It is well to divide the handlers into at least two sets. Gambier is very useful, especially to the greener goods, and if hemlock and other extracts are employed, their appropriate place is in the forward handlers or earlier layers. New valonia liquors must be avoided, but old layer liquors of considerable strength (up to 40° Bark. where the handling is long continued) may be employed.
Fig. 42.
At the end of this period, the butts are taken to the "layers" or "bloomers," in which they are laid down with stronger liquors and much larger quantities of "dust"; the latter is usually bark or valonia, though mimosa is occasionally used. The liquors vary from 40° to 60° or 70° Bark. in strength in mixed tannage, and the duration of each layer from 10 days in the earlier stages to a month in the later ones. For the best heavy tannages, 6-8 layers are required. Each time the butts are raised, they should be mopped on the grain, to remove dirt and loose bloom. Strong valonia liquors, or heavy valonia dusting, causes a brown sandy crust to form on the freely exposed parts of the butts. This is removed in striking, but is sometimes very troublesome on rough dried dressing leather. In pure bark tannage, which, however, is gradually becoming extinct, the liquors used are of necessity much weaker, as it is extremely difficult to obtain liquors of more than 25°-30° Bark. from this material. The last layer, however, should always have liquors of the greatest strength which can possibly be obtained, or the leather will be deficient in firmness.
After receiving their last layer, the butts are well mopped or brushed and washed up in a clear liquor, and thrown over a horse to drain before going into the shed. In America, the Howard scrubber ([Fig. 43]) is generally employed instead of hand labour at this stage. It consists of 2 rotating wooden frames at the top of a pit, provided with brushes or birch-brooms, and, when in use, enclosed by a cover A, through a slit G in which the sides are inserted and drawn back, while water is supplied by the pump B. Sometimes the brush-drums are placed one above another, and the leather is passed in at the side.