VEGETABLE TANNAGE 47 



action and a good level colour. It is also necessary to main- 

 tain the rate of adsorption. All the aims are attained by 

 frequently moving the goods. Heavy leather is suspended 

 vertically in the pits of tan liquor and handled up and down 

 as well as forward from pit to pit. Such pits are termed 

 " suspenders." In the earliest suspenders it is indeed advan- 

 tageous to have the goods in constant motion. This is done 

 by suspending on wooden frames which are rocked gently 

 by mechanical power ; such pits are termed " rockers." 

 For dressing leather in which firmness and smooth grain are 

 not so essential, the goods may be paddled in the first 

 liquors. This is occasionally done with stronger liquors for 

 the express purpose of working up the " grain " pattern. The 

 goods after passing through the suspenders are usually 

 passed to " handler " rounds, in which they are moved less 

 frequently. In these pits the goods are laid horizontally 

 one above the other. One advantage of handlers is that 

 the goods flatten thoroughly and straighten one another by 

 their own weight ; another is that more goods can be placed 

 in one pit than in suspenders. They are not so convenient 

 to work, however, as suspenders, and the goods do not feed 

 so rapidly. Hence the tendency is now to tan more in 

 suspension, and to economize labour by an extension of 

 the rockers. The handling of the goods is also saved by 

 pumping the liquors and by working rounds of suspenders 

 or rockers like the press leach system, with the difference 

 that the stronger liquor is pumped in to the head pit, and 

 the liquor passes upwards through the goods. 



Finally the goods are placed in " layers " or " layaways," 

 in which they remain undisturbed for a decidedly longer 

 time. These pits contain the strongest liquors of the yard, 

 and their principal function is to complete the tannage and 

 give weight and firmness by the adsorption of bloom, reds, 

 etc., in the interior of the hide. The goods are placed in 

 horizontally, and are dusted in between with fresh tanning 

 material which maintains the local strength of the liquor 

 and keeps the goods somewhat apart. Drum tanning attains 

 a more rapid penetration of the pelt by giving constant 



