Masonry oven these primitive-looking ovens were still being produced in Barnstaple potteries as late as 1890". A cloche or cooking bell is like an upside-down, fired ceramic bowl with a handle on top. It is heated in the fire along with a flat rock or open spot on the hearth. The prepared dough is placed on the hot rock or hearth floor, and then covered with the cloche, and perhaps hot coals or ashes for additional heat. The method goes back to ancient Egypt and Greece, and was probably the first form of masonry oven. It is possible to get some of
Conservation and restoration of ceramic objects to changes in humidity both high and low. In high humidity salts become soluble and in low humidity they crystallize. The changing from soluble to crystallization and back damages the surface of the ceramic because salt crystals are larger than liquid salt and therefore will shrink and expand the ceramic body. A white haze on the surface is the first indication of soluble salts, which is the salt crystallizing. Over time, the physical component of the body will crumble until it is completely destroyed. In the realm of conservation there are two distinct practices: non-interventive and active conservation. Non-interventive types