Study of cuprous chloride under pressure

Observations of large diamagnetic anomalies in rapidly warmed freshly prepared samples of CuCl under moderately high hydrostatic pressure are summarized and compared with the results of Brandt et al. The observations cannot be accounted for quantitatively in any simple way without assuming the existence of some new cooperative state. The possibility of the formation of fine-scaled metal-dielectric interfaces is considered. Proof of the existence or absence of superconductivity requires further experimentation.