Piezo-electric substances

A translation of a monograph, "Lss substances pieacutezoeacutelectriques syntheacutetiques," published in 1940, still of interest from the point of view of classification. The history of and tests for piezo-electricity are reviewed and the known piezo-electric substances are tabulated according to their crystal systems. The properties and applications of Rochelle salt are discussed and the piezo-electric constants of other artificial crystals are given.