Abstract
The dissociation of cyanite into mullite was studied. Bricks were made of various mixes and their properties are given. Twenty per cent is about the minimum amount of clay which will give the proper bond. It was found desirable in some cases to add MgO in small amounts to promote a crystalline bond between the dissociated cyanite grains and the bonding material. In Pt. II the phase rule equilibrium relations are discussed.