The piezo electric effect in the composite Rochelle salt crystal

The piezo electric effect is an electro-elastic property of certain crystals. It involves the conversion of mechanical into electrical energy, and also the converse effect. The paper presents an exposition of piezo-electricity and related optical and other properties belonging to these crystals. Special reference is made to the comparatively large piezo electric effects produced by Rochelle salt crystals prepared so as to develop the natural composite structure usually associated with substances which have been exposed to shearing stresses, in this case during growth. Applications of the piezo electric effect in such crystals to the transmission and reception of sound, are described and demonstrated.