Gerard W. Gawalt, curator of the exhibition, said that the ink Jefferson used was made of charcoal, iron filings and oak gall.

The idea of the vats of the mind reminds me of an occasion when I was walking on the Appalachian Trail in Pennsylvania with some friends, who showed me an oak gall.

He didn't grimace at the idea of the bitter tea; at this point he would drink down oak gall if it would help his head.

Oak Galls Q. Our pin oak tree has several oak galls.

The gallotannic acid was usually extracted from oak galls (also known as "oak apples"), or galls of other trees; hence the name.

I need to talk to Nivor about the latest oak galls.

Cerryl lifted the bin and dumped the contents - leather trimmings too small for anything, palimpsest scrapings, squeezed oak galls - over the side of the wagon, then stepped back.

The other form is called gallotannic acid and is found in oak galls.

Soot, iron salts or tannic acid made from oak galls, the swellings on oak trees formed around gall wasp eggs, were mixed with gum and water to make ink.

The spontaneous chemical reaction caused by the penetration stimulates the leaves to produce a roundish hard ball called an oak gall.