Peter smiled. "Carmachel told me nothing in a tannery was wasted," he said. "I was surprised to find that even the lumps of fat and bits of flesh adhering to the skins, together with the parings that came off when the calfskins were trimmed down to an even thickness, were disposed of for glue stock or fertilizer." "Every scrap of stuff is used, I can tell you!" assented Jackson. "Calfskin, you know, is never split; it is not heavy enough for that. Besides it is more nearly uniform in weight than a skin like a bull's hide, for instance, which is very much heavier about the head. No, calfskin is fairly even and therefore, while wet, is just put between rollers where a thin, sharp blade shaves from the flesh side any part of it that is thicker than any other. It comes out of equal thickness all over. Do you understand?" Peter nodded. "And now have you this beamhouse process straight in your head so we can go on?" Jackson held up his hand and began to check off the successive steps on his fingers: "The skins are washed until the dirt and salt are out; they are worked in paddle-wheels, if necessary, until soft; they are limed; unhaired; and bated, or puered. By puering I mean that they are put through a liquid that takes out all the lime; if the lime is not carefully soaked out the skins will be burned and hard and cannot be tanned properly. After the puering the short-hairers remove any remaining hairs; the skins are thoroughly washed again, and at last are ready for tanning." "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." "Or what?" "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.