strength and deformation properties of granite, basalt, line and .tests indicated,that the rock within each rock type was quite uni- form. Results of the unconfined compressive strength tests on basalt indicated that as the loading rate was increased from 1 to 1.60 x 10 psi/sec, ultimate strength, total axial strain, and Young's modulus of elasticity increased. Total diametral strain decreased as.compressive strength of black basalt,Strength and deformation properties of granite, basalt, line .The difference in the unconfined compressive strength between the slow and the rapid rates of loading for the rocks tested varied considerably. The dynamic compressive strength factor for the granite was less than l; for the basalt, 1.35; for the line,. 1. 52; and for the tuff, 1. 74. The compressional wave velocity of.