Kenny Belk, age 11, of Florence, S.C., for his question:

HOW DO YOU TAN A HIDE?

Two different methods for tanning hides are used by manufacturers: the mineral tanning system and the vegetable tanning method.

In the mineral tanning system, which is also called chrome tanning, the hides are soaked in a solution of acid and common salt for from four to eight hours. Paddle wheels in the pickling tanks move the hides around. The hides are then taken out of the tanks and piled flat to drain for one or two days.

With the vegetable tanning method, a bitter ingredient made from the leaves, nuts, bark and wood of such trees and plants as the chestnut, hemlock, mangrove, oak, sumac and wattle is used. The material is called tannin or tannic acid. The hides soak from 15 to 100 days.