Gathering and Grading Oak Galls: Blue Galls Before the Insect Escapes (Tomlinson, 1854)

"The best galls, known in commerce as black or blue galls, ... are gathered before the insect has escaped."

During the season walk the oaks often and watch the galls grow on the shoots and branches. They are hard, round and knobbed, from pea to nutmeg size.

Pick them as soon as they reach full size and weight, before the insect inside matures and bores out through the shell; any delay spoils them.

Sort the heavy, bluish 'blue galls' with no hole (the best, for ink and black dye) from the larger, lighter, brownish or yellowish 'white galls' with a small round hole (inferior). Check doubtful ones by weight; a whitish gall dyed blue shows too deep a colour, is light, and has the hole.

From Charles Tomlinson (ed.), **Cyclopaedia of Useful Arts** (1854), vol. I, "Galls", pp. 734-735 and Fig. 1017 (checked on the archive.org scan cyclopaediaofuse01tomluoft). He describes the Aleppo and Smyrna galls of Quercus infectoria.