Sagger: a Fireclay Box Moulded Round a Wooden Mould (Bourry, 1911)

The kiln box that shields ware from flame and soot: a fireclay-and-grog slab beaten flat, rolled round a wooden mould for the wall, joined to a slab bottom by hand, then dried and burned. Saggers stack in piles with wads of soft fireclay between. Usually oval, sometimes square or rectangular; size to suit the ware. Source: Emile Bourry, A Treatise on Ceramic Industries (1911), pp. 233, 352-356. Unknown: proportions, sizes, firing temperature. Picture: Fig. 173 of the book.