A method is described for determining the variation of the modulus of elasticity of solid bodies with respect to temperature. Sonic frequencies of various ceramic materials made into bar specimens were determined at various temperatures, and modulus of elasticity values were then calculated. The effect on the modulus of elasticity of a crystalline inversion within a bar was apparent even though the inverting material was a small percentage of the bar composition. Various other effects that change Young's modulus with temperature were also observed. Examples of the method are given and an analysis of results is presented.

not Available.

The need for an electrically heated furnace capable of operating at elevated temperatures and with an oxidizing atmosphere undoubtedly is great.The development work by Mr. Davenport and his co-workers in applying the principle of transfer of energy by means of the high-frequency apparatus to the ceramic resistor rings is most commcndable. The other furnace developments are also of great interest.At Stupakoff we have produced for a third of a century small ceramic glowers of the type useful for infrared spectrographic and other uses. We have also made resistor cylinders and rods from high-temperature-resistant ceramics.The following Stupakoff-owned patents may be of interest to researchers and engineers following the art: (I) U. S. Pat. 2,397,445-S. H. Stupakoff, "Electric Resistance Element." (2) U. S. Pat. 2,398,866, Canadian Pat. 437,356-R. E. Stark, "Activating Conductors of the Second Class." (3) U. S. Pat. 2,417,953-S. H. Stupakoff, "High Temperature, Elcctrically Heated Furnace" (quoted in the Davenport, et. al., paper).A few comments relative to each of the above may be of factual iiitercst.U. S. Pat. 2,397,445 discloses the art of combining electric resistance conductors of the first class with resistive conductors of thc second class for use at high temperatures.U. S. Pat. 2,398,866 discloses methods of initiating conductivity of glower elements of the second class where original cold resistance is infinitely high. Methods for sustaining multiple units of glowers individually and collectively from a constant current supply a t relatively modest potentials and energized from a constant potential source is also a matter of record.We note that the authors of this paper feel that in Stupakoffs U. S. Pat. 2,417,973 the current available a t the glower ends would be quite limited. It is noted with interest that air a t the elevated temperature of the end terminals is quite conductive and, as the authors point out in section VII (l), spacing between elements where a crack exists offers little resistance "so that the current should arc across the crack with little observable effect." It is a fact that the available potential across the terminal gap is sufficient to convert the air dielectric into a virtual conductor and the 12R loss would be small in comparison with that of the resistive conductive element, which is doing the actual heating of a furnace.We a t Stupakoff have read with interest R. F. Geller's comments on this paper, We have also had the pleasure of inspecting his furnace, and while it has been quoted as being small and costly, we must realize that induction heating equipment likewise is quite costly.The fact that the authors have made a larger operative unit than the Geller furnace is commendable and should be an incentive to many others to develop and make similar or larger furnace units. Mixtures of MgO andTic were sintered at four temperatures in an induction furnace using a helium atmosphere. X-ray patterns of the sinters were made and interpreted. Colors and appearance were noted and weight ...

A modified procedure for the determination of boric oxide in glass, based on the work of Hollander and Rieman, has been shown to offer considerable advantages in speed and accuracy over procedures currently used for the determination of boron in soda-lime and borosilicate glasses.Mixtures formulated from MgO-TiN-NiO were investigated in a search for a high-temperature refractory material. Components were selected on the basis of their physical and chemical properties. Sintering was performed in a protective argon atmosphere. NiO was reduced or dissociated to nickel metal during the sintering operation. Titanium nitride was introduced to promote a bond between the metallic phase, nickel metal, and the ceramic oxide, MgO. Data is presented for three compositions evaluated for transverse strength, resistance to oxidation expressed as per cent weight gain, and thermal shock in terms of transverse strength. Several compositions exhibited increased transverse strength after being exposed to a n oxidizing atmosphere.Journal of The American Ceramic Society-Ilower, Londeree, and Ueltz Vol. 34, No. 10 X-ray diffraction charts of the internal structure of composition point 9 after 0, 24, 100, and 300 hours of oxidation at 200OOF.

Dielectric and physical properties are listed for fifteen oxides which are included in the glass phase of a steatite body. Data from electrical measurements made at 500, 600, 1000, and 1100-kc. frequencies and at 25O, 85". 120°, and 150°C.The results of petrographic examination are noted for each body. A systematic classification in terms of the periodic table indicates correlative characteristics with respect to valency and atomic weight.A review of the literature is cited. are included.