Two areas of capitation research have met with limited success until recently: (1) the measurement of the strength or cavitation threshold of pure (mote‐free) liquids; and (2) the prediction of the threshold of liquids known to be “impure.” Advances in these areas are reviewed and new results are reported. The influence of mote size and mote wetability on the cavitation threshold has been studied theoretically [R. Apfel, J. Acoust. Soc. Amer. (to be published)]. Results of this work bring some semblance of order to a wide variety of cavitation observations. By minimizing the number of motes in the liquid sample and by isolating the sample from solid container surfaces, it is possible to measure the strength of pure liquids. This has been accomplished by testing small filtered droplets of the sample suspended in an “inert” host liquid. Furthermore, the tests have been performed at temperatures at which the sample has undergone significant super heating; under this condition, the predicted tensile stresses are low enough to be accessible experimentally. This technique [R. Apfel, J. Acoust. Soc. Amer. (to be published)]has been modified with the intention of studying the liquid‐to‐solid phase transition. [Work supported by the Office of Naval Research.]