‘The Electrical Expansion of Quartz’ by Jacques and Pierre Curie

The history of ultrasound commonly traces its origins to the discovery of the piezoelectric properties of quartz by the Curie brothers, Jacques and Pierre. The original papers are commonly cited but are difficult to find in English translation. The purpose of this article is to make available in translation their concluding paper, published in 1889, in which the Curies gave a rather more complete description of their work. It is of particular interest because it is their only paper on piezoelectricity that included figures showing the instruments they had developed. The paper concentrates on the prediction and measurement of the extremely small strains created in quartz crystals when placed in an electric field. It sets the foundation for the subsequent use and exploitation of quartz in a variety of applications including the first practical transducer for ultrasonic pulse-echo detection.