René Just Haüy () FRS MWS FRSE (28 February 1743 – 1 June 1822) was a French priest and mineralogist, commonly styled the Abbé Haüy after he was made an honorary canon of Notre Dame. Due to his innovative work on crystal structure and his four-volume Traité de Minéralogie (1801), he is often referred to as the "Father of Modern Crystallography". During the French Revolution he also helped to establish the metric system.

Biography

Early life

René-Just Haüy was born at Saint-Just-en-Chaussée on February 28, 1743, in the province of Picardy (later the département of Oise). His parents were Just Haüy, a poor linen-weaver, and Magdeleine Candelot.

After his ordination, Haüy became regent (teacher) of the second class at the Collège du Cardinal-Lemoine.

His brother Valentin Haüy was the founder of the first school for the blind, the Institution des Jeunes Aveugles (Institute for Blind Youth) in Paris.

Crystals that had been classed together previously were identified as being of separate mineral species if their fundamental structure differed. Heavyspar, for example, was differentiated into specimens containing barium and strontium.

thumb|right|Haüy with a contact goniometer, ca. 1812

Haüy and his contemporaries worked with limited evidence. They could observe a crystal's habit and cleavage planes and measure interfacial angles The internal structure underlying the crystal's integrant molecule would not be determinable until the development of X-Ray diffraction technology many years later, in 1902. This idea was fundamental to later developments in the field on crystal lattices.

Between 1784 and 1822, Haüy published more than 100 reports discussing his theories and their application to the structure of crystalline substances. Haüy worked out the mathematical theory of his work in his Traité de minéralogie (1801), which became a classic in the field. A second updated edition appeared as Traité de cristallographie in 1822.

Haüy is also known for his observations on pyroelectricity. He detected pyroelectricity in calamine, an oxide of zinc, as early as 1785.

He studied pyroelectricity in a number of other minerals including tourmaline and related them to crystalline structure. He showed that electricity in tourmaline was strongest at the poles of the crystal and became imperceptible at the middle.

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.

On November 9, 1794, Haüy also became a professor of physics at the École normale supérieure. On November 28, 1803, Haüy became one of the first recipients of the Order of the Légion d'Honneur. but still often misreported.

Recognition

thumb | right | [[Haüyne crystals ]]

In 1817, René-Just Haüy was elected an honorary member of the New York Academy of Sciences.

His name is the thirteenth inscribed on the south-east side of the Eiffel Tower.

The mineral Haüyne was named for Haüy in 1807 by Thomas-Christophe Bruun-Neergaard. It occurs in silica-deficient igneous rocks in a wide variety of locations.

Works

The following are Haüy's principal works:

  • Essai d'une théorie sur la structure des crystaux (1784) via Gallica
  • De la structure considérée comme caractère distinctif des minéraux (1793)
  • Exposition abrégé de la théorie de la structure des cristaux (1793) BNF
  • Extrait d'un traité élémentaire de minéralogie (1797)
  • Traité de minéralogie (5 vols, 1801) BNF: Vol 1 Vol 2 Vol 3 Vol 4 Vol 5
  • Traité élémentaire de physique (2 vols 1803, 1806) Google Books
  • Tableau comparatif des résultats de la cristallographie, et de l'analyse chimique relativement à la classification des minéraux (1809) BNF
  • Traité des pierres précieuses (1817) BNF
  • Traité de cristallographie (2 vols, 1822) Google Books

He also contributed papers, of which 100 are enumerated in the Royal Society's catalogue, to various scientific journals, especially the Journal de physique and the Annales du Museum d'Histoire Naturelle.

See also

  • Centered octahedral number
  • List of Roman Catholic scientist-clerics

References

  • George F. Kunz. “The Life and Work of Haüy.” American Mineralogist. Volume 3, number 6, 1918. Pages 61–89, plates 5–11; Also: Bulletin of the New York Mineralogical Club. Volume 3, pages 61–89, plates 5–11 [sic]. This was for the celebration of the 175th anniversary of the birth of the famous French mineralogist.
  • François Farges, Haüy 2022.