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Running of glaze over its proper limits on vertical sur- faces is caused by excessive fusibility or fluidity of the glaze. Stunting, or dunting, of the body may be due to rapid cooling of the kiln, but is most liable in bodies nearly vitrified. In more open bodies those having a high flint content tend most in this direction, the reason being the curious curve of flint in thermal expansion and contraction. Generally, non-plastic ingredients tend more to stunting than plastic ones. Cracking during drying is caused by uneven thickness of the ware or by irregular drying. Dipping is another cause of loss before going into kiln. It may be the fault of the dipper or of the glaze. " Ropey " glazes are too viscous, and do not throw excess glaze off the biscuit after dipping. Mayer states that this can be remedied by the addition of 0.4-0.8 per cent, magnesium sulphate to the slop. Crooked Ware results from uneven temperature in the kiln, or from excess of magnesia, lime or soda in body ; also from uneven support of the ware in kiln. Stuck Ware also results from bad placing in kiln. Sulphur, whether in the coal, or as pyrites, or sulphate in the body, or as sulphates in the glaze, must be avoided as much as possible, especially in the glaze. The sulphur oxides are not driven off till a high temperature has been reached, with the almost inevitable consequence of bubbling