An apparatus has been developed for measuring linear compressibility and its temperature coefficient in the pressure region from 1 to 10,000 kg/cm2 and up to 500° C., for materials which can be shaped into cylinders about 4.5 cm long and 0.6 cm in diameter. The apparatus is described, with preliminary results for lead, aluminum, fused silica, obsidian, and an artificial diabase glass. The results for the glasses are highly special or even anomalous, showing very small positive or negative temperature coefficients of compressibility.
The development of seismology has resulted in increasingly precise and numerous determinations of the velocities of propagation of elastic waves in the materials of the earth's crust. Assuming the validity of certain familiar equations from the theory of elasticity, these velocities may be used to compute the elastic constants of the earth materials. The elastic properties of many representative rocks and minerals having been independently . . .