33-4 KEPORT OB' COMMISSIONER OF FISH AND FISHERIES. 



lation. The skins aiv put iirst into tin old-linic solution :ind frequently 

 changed to strong-er sohitions until the liming (^tl'ect is eoinplcted, 

 three or four weeks being generalh' required for this operation. 



The action of the lime is usuall}' hastened bj' frequent " handling-" 

 and changing the skins from one tank to another. When the bulbous 

 roots of the hair are thoroughly loosened, the skins pass to the flesh- 

 ing house where each one is separate!}" laid on a beam and carefull}^ 

 unhaired on one side and fleshed on the other. In some establish- 

 ments the skins are partly imhaired before the liming process is com- 

 pleted. The choicest grades of hair are used largely by plasterers, 

 but most of it is suitable only for fertilizer or tlie waste heap. After 

 a thorough washing and ''striking out,'' currier fashion, the skins are 

 in condition to be converted into leather. 



Owing to the excessive and irregular thickness of the skins, it is 

 desirable at this stage of the process to split or shave them, although 

 many tanners, especially those in the United States, postpone this 

 until the tanning is complete. The splitting is efi'ected with a machine 

 of clever mechanism, its principal parts consisting of two metal roll- 

 ers, revolving horizontallj" one above the other, between which passes 

 the skin spread out smoothl3\ The advance edge of the skin is pre- 

 sented to a keen blade, moving with great rapidity parallel with the 

 line of contact of the rollers, thus splitting the skin into two pieces of 

 equal superficial area, of which only the grain or outside portion is 

 desirable for leather-making. The other half is sometimes used for 

 making an inferior grade of leather, or cheap and somewhat deliques- 

 cent size or glue, but ordinaril}" it goes to the waste heap to be con- 

 verted into fertilizer. The thinned skins are puered Avith bran or dog 

 dung, followed by drenching and a thorough working out on a beam 

 to remove all traces of lime salts and other refuse materials, as already 

 described on page 331, and thus made ready for the tanning solution. 



The skins are next steeped in tanks or vats containing successively 

 stronger l)aths of the astringent infusion of oak bark, japonica, sumac, 

 or any other tanning agency. For fancy shades of coloring, sumac 

 onh' is used, as a rule. During the first few days the skins are fre- 

 (luently "handled," so that the liquor maj^ quickly strike through 

 them. This '' handling-' or "working" is cheaply effected by means 

 of paddle wheels, which turn the skins over and over in the solution. 

 The more thej^ are worked b}' the paddle wheel, the larger the grain 

 of the finished leather. From four to six weeks' time is usually 

 required to complete the tanning process, even with the use of paddle 

 wheels. In England and Scotland large quantities of the skins are 

 taimed by sewing together two skins, flesh to flesh, around the edges, 

 so as to form sacks or bags, which are then flUed with licjuid sumac. 

 This method is chciiper and gives a better color. It is also more 

 expeditious, re({uiring usually less than one Aveck. 



The tanned skins are next submitted to a sumac bath containing a 



