This report presents the results obtained in a study of sagger bodies and represents an enlargement of a similar study of a preliminary nature, the results of which have been published. The clays and grogs are combined to give bodies having wide variations in body structure and in the several properties which were studied. Data are given on the modulus of elasticity, transverse breaking strength, plastic flow, thermal expansion, and resistance to failure due to heat shock of thirty‐five laboratory prepared bodies and ten commercial bodies after firing at from one to three different temperatures. For comparative purposes data are given on two series of bodies, the one series containing coarse grog and the other fine grog. In addition body compositions were varied in order to compare the effect on sagger life of using open‐ and close‐firing grogs.