“How are they tanned?”
“Why, by putting them into paddle-wheels filled with the tanning solution where they revolve as many as seven or eight hours. This solution is then changed for a weaker one, and they revolve again for a couple of hours more. Some skins are tanned in a mixture of chemicals which we buy all prepared; we call those chrome tanned. Others are soaked in a vegetable tan of hemlock, oak, chestnut, palmetto roots, gambier, or quebracho.”
“Quebracho!” Jackson rolled out the long word with a gusto. “Quebracho is a tree something like the lignum-vitæ and grows in South America. The hardened gum comes in barrels and looks like rosin; sometimes, instead of being hard, it is shipped in a liquid state in big tank cars. There is about fifteen per cent. of tannin in quebracho and at the tanneries it can be diluted, of course, to any strength desired. We use it altogether here instead of using other vegetable tans.”
“But it says in my geography that every one uses oak or hemlock bark,” objected Peter, sceptically.
“Well, the Coddington Company doesn’t. Bryant says we tan so much leather here that there would be no way of disposing of the quantities of bark left after the tannin had been extracted from it. Besides bark is scarce and expensive; then, too, it takes a car-load of bark to get even a decent amount of tannin and the freighting adds to the cost. Quebracho can be shipped by water and is therefore more economical, and for the varieties of leather we tan here it answers the purpose as well. It is lots of work to get the tannin out of oak or hemlock bark. The bark has to be ground up and put in a leaching-kettle full of water; after it has boiled the liquid is drained off and the tannin extracted. Using quebracho is a much simpler method. Of course we use oak and hemlock bark, though, in the sole leather tanneries over at Elmwood.”
Peter regarded Jackson intently.
“How did you come to know so much about all this business?” he asked at last.
“Oh, I don’t know much,” was the modest answer. “I just wanted to learn what I could while I had the chance. You can’t help being curious when you work so long in one room. Bryant saw I was interested and he’s explained all the things I wanted to find out.”
“Then maybe you’ll pass on some more of your information,” laughed Peter, “and tell me why some of the skins are tanned in quebracho and some in chrome.”