The complete stress‐strain equation of state for a granodiorite and two graywacke sandstones has been determined on loading to 20 kb axial stress at room temperature. Data under conditions of hydrostatic, uniaxial stress at various confining pressures and uniaxial strain loading are synthesized to define the behavior of these rocks. For the granodiorite it is observed that the onset of dilatancy as well as intersection of the failure envelope is independent of loading path. No dilatant behavior is observed on uniaxial strain loading to 12 kb axial stress. Both sandstones are observed to load below the hydrostat (increased compressibility) in either uniaxial stress or uniaxial strain loading. This enhanced compaction at relatively low pressures is believed to result from the influence of the additional shear stresses, which facilitate intergranular movements in these porous rocks. Dilatant behavior greatly diminishes at higher mean stresses where the rock undergoes a transition in failure mechanism from throughgoing narrow tensile and shear fractures (predominantly intergranular) to pervasive small‐scale fracturing (predominantly intragranular). Dilatancy again becomes important at the highest stresses, where most of the initial porosity has been removed. The data on both rocks are used to delimit areas of characteristic behavior that are uniquely defined in stress space, independent of loading path.

The volume compressibilities of BeO, ZnS, CdS, CdSe, and CdTe have been measured to 45 kbar. Solidsolid transitions were observed in CdS, CdSe, and CdTe at 17.5, 21.3, and 31.8 kbar, respectively, with corresponding volume changes of 16.0%, 16.4%, and 16.4%.

The hydrostatic compressions (ΔV/V0) of granodiorite, basalt, dolomite, and tuff (all from the Nevada test site), Indiana limestone, two rock salts, and anhydrite were measured to 46 kb at 25°C. A phase transition was observed in anhydrite (CaSO4) at 19.6±0.5 kb with a volume change of 4.1 per cent. The compression data for granodiorite, basalt, dolomite, tuff, and limestone were in good agreement with dynamic results for similar rocks.

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The effect of pressure to 150 kbars has been measured on the absorption spectra of five nickel complexes. The results are discussed in terms of the change of 10 Dq and of the Racah parameter B, with pressure. In general 10 Dq, the crystal field strength, increased with pressure, but the increase noted was not the same when calculated for the different peaks of a given complex. This discrepancy may be described in terms of changes of covalency as measured by changes of the Racah parameter B. In general B decreased with increasing pressure showing increased covalency at high pressure. There were some discrepancies in the value of B obtained from different transitions. These may be the result of experimental error, but may also be associated with distortions of the field, or with weaknesses in the assumption of point charges or dipoles.

The compressions of Li7H, Li7D, Li6H, and Li6D were measured to 40 kbar at 23°C. The data fit well to both the simple Born-Mayer model and the Murnaghan equation. The 1-atm compressibilities varied from 2.8 to 2.9 mbar−1. The data do not agree well with other reported results.

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This paper presents a method for overcoming temperature and pressure limitations inherent in conventional techniques for measuring equilibrium thermodynamic data. The method can be applied to conducting materials that can be resistively heated and that do not dissociate in the liquid phase; and it is thus particularly suitable for investigating pure liquid-metal thermodynamic data. The technique has been applied extensively to lead at temperatures exceeding 5000 K and at pressures up to 2 kilobars. A cylindrical material specimen 1 mm in diameter and 25 mm long is interposed between two current leads and mounted axially concentric with a high-pressure cell. After the cell is pressurized with helium, a current pulse from the overdamped discharge of a high-voltage capacitor bank heats the wire at such a rate that its expansion is nearly isobaric. The energy deposited in a central segment of the sample is computed by integrating the product of the current flowing in the segment with the resistive voltage developed across it. With these data, sample resistance can also be calculated during a major portion of the time that current flows. Because mounting constraints limit sample expansion to the radial dimension, the equilibrium volume is calculated from the expanded diameter, which is measured by means of pulsed x-radiography.