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Application of uniaxial stress to a sample of granite causes elastic wave velocity anisotropy. Compressional waves travel fastest in the direction of the applied stress. Two shear waves travel with generally different speeds in any direction, exhibiting acoustic double refraction which increases with increasing stress.

The total thermal conductivity (lattice plus radiative) of several important earth materials is measured in the temperature range 500°–1900°K. A new technique is used in which a CO2 laser generates a low‐frequency temperature wave at one face of a small disk‐shaped sample, and an infrared detector views the opposite face to detect the phase of the emerging radiation. Phase data at several frequencies yield the simultaneous determination of the thermal diffusivity and the mean extinction coefficient of the material. The lattice, radiative, and total thermal conductivities are then calculated. Results for single‐crystal and polycrystalline forsterite‐rich olivines and an enstatite indicate that, even in relatively pure large‐grained material, the radiative conductivity does not increase rapidly with temperature. The predicted maximum total thermal conductivity at a depth of 400 km in an olivine mantle is 0.020 cal/cm sec °C, which is less than twice the surface value.

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The velocity Vp of compressional waves has been measured in rock samples of low porosity to confining pressures Pc of 2 kb for a number of different constant pore pressures Pp. An effective pressure defined by Pe = Pc − nPp, n ≤ 1, is found to be the determining factor in the behavior of Vp rather than an effective pressure defined simply by the differential pressure ΔP = Pc − Pp. As pore pressure increases at constant effective pressure, the value of n increases and approaches 1, but as effective pressure increases at constant pore pressure, the value of n decreases. These observations are consistent with Biot's theory of the propagation of elastic waves in a fluid‐saturated porous solid.

The velocity of shear waves is reported as a function of pressure for several rocks previously used by Birch in his measurements of VP. AC‐cut quartz transducers with resonant frequencies of 1 to 5 Mc/s were used with the usual ultrasonic technique. In fine‐grained, low porosity rocks, very little compressional energy precedes S and there is no ambiguity in arrival time. No systematic difference exists between previous measurements on several of the same rocks made by Birch using resonant torsional vibrations of long cylinders. Chief advantages of the ultrasonic technique are the ease with which measurements may be made and the fact that both VP and Vs may be measured on the same specimen. Analyses of the data will be given in part 2.

The elastic properties of several rocks, fused quartz, aluminum, and steel were calculated as a function of pressure to 10 kb from measured velocities of P and S waves in three directions. Compressibility calculated from Vp and Vs is within a few per cent (and therefore within the experimental error) of that measured directly by the use of strain gages, for pressures which range from 3 to 9 kb. Comparison is also good for fused quartz, steel, and aluminum, as well as for fine‐grained limestone at atmospheric pressure. At atmospheric pressure a discrepancy of several hundred per cent between static and dynamic values is probably due to the different effects of cracks in the rocks on the two measurements. The good agreement of the two sets of compressibilities at pressures greater than 2 kb implies that other elastic properties calculated from velocities will be in good agreement with static values.

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