For engineering applications of underground nuclear explosions it is necessary to know the properties of the material in which the explosion takes place. Many organizations provide measurements of the properties of interest, but their techniques are not always fully suited to the specific needs of Lawrence Radiation Laboratory. Core data are often unavailable or, if available, are not useful. Therefore, a number of systems have been developed at this Laboratory to measure, in place and under especially difficult conditions, such properties of earch materials as density and acoustic velocity. We have also developed some techniques for increasing the usefulness to us of measurements made by others, generally by providing calibrations more suited to the rock types in which we work.