that electricity in tourmaline was strongest at the poles of the crystal and became imperceptible at the middle. Haüy published a book on electricity and magnetism, Exposition raisonné de la théorie de l'électricité et du magnétisme, d'après les principes d'Æpinus, in 1787. On February 12, 1783, Haüy was elected to the Académie royale des sciences de Paris (French Academy of Sciences) with the rank of an adjoint in botany, there being no vacancy in either physics or mineralogy. In 1788, he became as an associate in natural history and mineralogy. French Revolution During the French Revolution, Haüy refused to take an oath accepting the Civil Constitution of the Clergy, and became a non-juring priest. He was thrown into prison after the monarchy was overthrown on August 10, 1792. Étienne Geoffroy Saint-Hilaire interceded on his behalf. Haüy was released just a few days before the September Massacres of September 2–7, 1792 in which many of the clergy were killed. On August 8, 1793, in spite of the efforts of Antoine Lavoisier, the Académie royale des sciences de Paris was dissolved by the National Convention. It was not restored until August 22, 1795, when it became known as the Institut National des Sciences et des Arts (National Institute of Sciences and Arts). Before its suppression, the Academy of Sciences had formed a working group to develop a uniform system of weights and measures for use throughout France. Lavoisier was a major proponent, and on March 30, 1791, he submitted a plan on behalf of the Commission on Weights and Measures, which was adopted by the Constituent Assembly. Lavoisier and Haüy were tasked with determining the density of water. As of January 4, 1793, they determined the weight of a cubic decimeter of distilled water at the temperature of melting ice, the kilogram. On August 1, 1793, the National Convention passed a decree, in favor of developing uniform weights and measures across France. On September 11, 1793, they established a Temporary Commission of Weights and Measures made up of twelve scientists, including Haüy, whose task was to carry out the decree. The work of the commission was disrupted by political events. In November 1793, Lavoisier and several others were arrested and removed from the Commission. On May 8, 1794 Lavoisier was guillotined. Nonetheless, Haüy remained secretary of the Commission through this turmoil. The law of 18 Germinal an III was enacted on April