An earthenware compartment or oven, often shaped like a half cylinder, used in furnaces to protect objects heated from the direct action of the fire, as in scorification of ores, cupellation of ore buttons, etc.
fire-clay box in which glass (or porcelain) objects are enclosed, when placed in the muffle kiln, to protect them from the flames and smoke while being subjected to low-temperature firing, especially in the process of firing enamels and gilding at temperatures of about 950-1320°F (500-700°C).
A vaulted or arched, flat-bottomed earthenware vessel, open at one end and closed at the other, placed in a furnace* to afford a space shielded from actual contact with the fuel; sometimes with openings at the side; often placed over a cupel*.
A muffle furnace is a (usually) front-loading box-type oven or kiln for high-temperature applications such as fusing glass, creating enamel coatings and ceramics. They are also used in many research facilities, for example by chemists in order to bake the moisture out of a sample to ensure it is completely dry.