THE FREEZING OF PYROMETRIC CONES *

A bstract Pyrometric cones are sometimes subjected to atmospheric or firing conditions which cause a misbehavior known as “freezing.” Under such conditions, the cone may not come down until a higher temperature, sometimes two or three cones higher, is reached. Definite conclusions have not yet been reached as to the cause of this action. Through petrographic and X‐ray analysis, however, certain definite ideas have been formulated which have served as a basis for the development of a series of nonfreezing cones. These cones have been used under conditions where freezing is ordinarily produced and were found to act normally, recording the true heat work.