A process of tanning with alum, used in combination with salt, egg yolk and other substances. Used for the original feathery golf balls. "In 1845 we more than doubled that. Hard work it was. I can still smell the leather, feel the heat. We used to use a chest clamp to literally compress and push those goose down feathers into the ball. Of course you cut six strips of bull hide and you soaked it in alum and of course you took three of 'em and stitched them inside out there, and the feathers went back in, and you compressed and compressed, and the idea being that as the leather shrinks as it dries out and the feathers expand. Then that gives you the compression." Quoted by Wally Uihlein, Sept 1998, at St.Andrews Golf Congress.