The wetting of alumina‐silica refractories by a soda‐lime‐silica glass at 1200°C. was studied by taking measurements from enlarged photographs of a glass drop on the refractory surface after various time intervals. The values calculated for the contact angles were in agreement with those obtained by direct measurement of the solid‐glass‐air interfaces. A review of the theoretical considerations validating the use of the contact angle as a means of measuring the wetting tendency is presented. The physical conditions which can influence the magnitude of the contact angle are also discussed, as is the method of calculating the contact angle. The rate at which the contact angles decreased indicated that an appreciable difference exists in the tendency of the molten glass to wet the various alumina‐silica refractories. A comparison is made of the wetting behavior of the refractories studied.

This portion of the investigation indicates the importance of the wetting behavior of molten glass to its rate of penetration into the same refractories studied in Part I. The principles concerning the penetration of liquids into porous solids are discussed. The rate of penetration of the glass into the refractories was evaluated by two methods with good correlation. Further information concerning the penetration of the glass into the refractories was obtained from a study of sections of the glass‐refractory interfaces. The relative resistance of each of the refractories to the penetration of the glass was evaluated. By a modification of the “pressure displacement method,” the effective pore sizes of the refractories were determined. The average pore radii of the refractories tested are compared. A break was observed in the relationship between the rate of penetration and the pore size of 99% alumina bodies with two liquids of markedly different properties. An explanation for this sudden change in the rate of penetration has been given, based upon the change in pore volume with change in pore radius.

A furnace with a tungsten coil as the heating element has been designed and built for use with the X‐ray diffraction spectrometer in the study of phase changes and equilibria at high temperatures. Tests indicate that temperatures up to 2000°C. can be reached and maintained for long periods of time in a neutral atmosphere. Materials which are not readily affected by the tungsten vapors that are present can be heated successfully in this type of furnace. Summary With this furnace, samples may be heated to and held at temperatures up to 2000° C. while X‐ray spectrometer data are obtained. Phase changes and equilibrium conditions existing at temperatures considerably above those obtainable with Pt alloy elements and at different time intervals at constant temperatures can thus be readily and positively determined. It should be noted, however, that materials which are readily reduced by tungsten vapors cannot be satisfactorily heat‐treated in this particular type of furnace.

Factors which cause variations in the finished size of clay products are determined. These are classified in the order of their importance, and limits are established within which the factors must be controlled to reduce these variations to a point which is consistent with the commercial production of modular products.The factors found to have the greatest effect on the finished size are soaking temperature and soaking time. Those factors having a lesser effect are (1) firing atmosphere, (2) relative amounts of clay mineral and quartz present in the clay in the different parts of the pit, (3) grain size of the clay produced by grinding or weathering, and (4) deairing treatment.