BY-PRODUCTS OF FISHERY INDUSTRIES 229 



not pursued so relentlessly; for this reason there 

 are still many large herds. 



The process used in the preparation and tanning 

 of seal skins is practically the same as the process 

 employed in the tanning of the skins of land animals, 

 except that the finishing process is somewhat dif- 

 ferent. After the tanning process is completed, the 

 skins are dampened with a coat of season containing 

 blood albumen and are then rolled on the glazing 

 jack until a bright finish is obtained. When an 

 especially bright finish is desired, the skins are 

 dampened a second time and again rolled. The final 

 finish which is so characteristic of seal leather is ob- 

 tained by a process known as boarding. This is 

 accomplished by rolling the skins in such a manner 

 as to produce miniature wrinkles running at different 

 angles along the grain. Seal and walrus leathers are 

 used in suitcases, traveling-bags, and the like. 



Porpoises, dolphins, blackfish, and whales are 

 marine mammals which resemble each other in many 

 respects. Porpoise, dolphin, and blackfish skins have 

 been used in the preparation of high-grade leathers 

 for many years, but whale leather has never found 

 an important use. Porpoise leather has been made 

 to imitate cordovan, and produces a very worthy sub- 

 stitute. But since it is exceedingly strong, it finds 

 its principal use in the preparation of lace leather, 

 which is used for lacing up machinery belting. Por- 

 poise lace leather is prepared by tanning the skins 

 first with alum and salt and then with cod oil, after 

 which the leather is oiled with a mineral oil. The 

 product is very strong and flexible. 



