Background

Antoine César Becquerel was born on March 7, 1788, in Châtillon-sur-Loing, Loiret, France. Becquerel’s father was serving at the French military as the royal lieutenant.

Education

Becquerel entered École Polytechnique in 1806 and became engineer-officer in 1808.

Career

On his graduation from École Polytechnique, Becquerel embarked on a military career in the Corps of Engineers, being promoted to captain in 1812. The following year he was appointed sous inspecteur of École Polytechnique; he returned to active service in 1814, but after the fall of Napoleon in 1815 devoted himself entirely to science.

Becquerel’s first studies were in mineralogy, and in association with Alexandre Brongniart, whose disciple he was, he discovered in 1819 a collection of important recent deposits at Auteuil that contained previously unknown crystalline forms of calcium phosphate. The study of minerals led easily to electrical experiments. Following up an observation that Iceland spar became electrified when compressed, Becquerel showed that this phenomenon was general, provided that the crystals under investigation were insulated; his studies on tourmaline became classics. This effect is called the piezoelectric effect and obtains only in crystals which possess no center of symmetry. From studying the electrical effects of compression, Becquerel moved on to thermoelectricity, investigating the electrical effects of heating minerals. He discovered various definite transition temperatures, at which the electrical state of a substance changes discontinuously. These researches led to experiments on the electrical measurement of temperature.

Of perhaps greater interest was Becquerel’s work on the voltaic cell. In the early decades of the nineteenth century, it was not clear whether the production of electricity in the cell was due to the mere contact of dissimilar bodies, or whether it depended upon a chemical reaction. The principle of conservation of energy had not yet been clearly enunciated; but Becquerel believed that there was a close relationship between electricity on the one hand, and heat, fight, and chemical forces on the other. In a series of careful experiments, he put it beyond doubt that electricity could be generated only by the contact of dissimilar bodies when they reacted together chemically, or differed in temperature, or were rubbed together. Conversely, he established that all chemical reactions can generate electricity. This was related to earlier work, notably by Humphry Davy, and in 1829 Becquerel employed Davy’s discovery that a battery could be made of two liquids separated by a solid barrier in the construction of the first battery that, not being polarized, could supply current at a reasonably constant EMF.

Using these cells, Becquerel performed elegant small-scale experiments on the synthesis of mineral substances. Since he was able to control his EMF’s, through secondary electrolysis he succeeded in obtaining crystals of various substances - notably sulfides - that had previously been produced only in an amorphous condition.

He suggested that the presence of crystalline substances in mineral veins might be accounted for by their having been deposited by electric currents operating over a very long period of time. Becquerel remarked that chemical synthesis had lagged behind analysis, and hoped that through his techniques many naturally occurring crystals would be synthesized and the balance thus redressed. It was for this work that he received the Copley Medal. These researches found industrial applications in the treatment of silver-bearing ores and the extraction of potassium chloride from the sea.

Becquerel wrote a great number of papers; of his joint papers, the majority were written in collaboration with his son, but his co-workers also included Ampère and Biot.

Achievements

• One of Becquerel's achievements was in the discovery in 1820 that pressure can induce electricity in every material, attributing the effect to surface interactions (this is not piezoelectricity). Thus, by 1825 he made a remarkable invention of a differential galvanometer for the accurate measurement of electrical resistance. In 1829 he invented a constant-current electrochemical cell, the forerunner of the Daniell cell.
  
  Another Becquerel's achievement was in the discovery in 1839 of the photoelectric effect on an electrode immersed in a conductive liquid. He was the first to prepare metallic elements from their ores by this method.
  
  Becquerel was elected to the Académie des Sciences in 1829; was awarded the Copley Medal of the Royal Society of London in 1837 for his various memoirs on electricity, and particularly for those on the production of metallic sulphurets and sulphur by electrolysis. When the chair of physics at the Muséum d’Histoire Naturelle was founded in 1838, Becquerel became its first occupant.
  
  His name is one of the 72 names inscribed on the Eiffel Tower.

Works

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  • Traité D'Électricité Et De Magnétisme, Et Des Applications De Ces Sciences À La Chimie, À La Physiologie Et Aux Arts 1855
  • Des forces physico-chimiques et de leur intervention dans la production des phénomènes naturels 1875
  • Elements d'electrochimie appliquee aux sciences naturelles et aux arts 1843
  • Traité Complet du Magnétisme 1846
  • Résumé de l'histoire de l'Électricité et du magnétisme 1858
  • Recherches experimentales sur l'action du sel dans la vegetation et sur son emploi en agriculture 1847
  • Traité d'électricité et de magnétisme, et des applications de ces sciences à la chimie 1855
  • Souvenirs Historiques Sur L'amiral Coligny: Sa Famille Et Sa Seigneurie De Chatillon-sur-loing 1876
  • Nouveau Manuel Complet De Galvanoplastie Ou Eléments D'electro-métallurgie 1849
  • Des Climats Et De L'influence Qu'exercent Les Sols Boisés Et Non Boisés 1853
  • Mémoire sur les forêts et leur influence climatérique 1865
  • Traité de physique considérée dans ses rapports avec la chimie et les sciences naturelles 1844
  • Éléments de physique terrestre et de météorologie 1847
  • Des Engrais Inorganiques En Général, Et Du Sel Marin 1848
  • Traité des Applications de l'Électricité à la Thérapeutique Médicale Et Chirurgicale 1857
  • Éléments De Physique Terrestre Et De Météorologie 1847

Membership

Becquerel became a member of the Académie des Sciences in 1829. He also became a foreign member of the Royal Netherlands Academy of Arts and Sciences in 1851.

Personality

Becquerel lived to a ripe old age, and his vivacity amazed his younger colleagues in the Academy, in the proceedings of which he took a lively and regular part to the end of his life.

Connections

In 1813 Becquerel married Aimée-Cécile Darlui, a relative of the Duc de Feltre, and became the founder of a dynasty of distinguished scientists. His son Alexandre Edmond Becquerel succeeded him at the Museum, and his grandson Antoine Henri was the discoverer of radioactivity.

Wife:

Aimée-Cécile Darlui

Son:

Alexandre-Edmond Becquerel

associate:

Alexandre Brongniart

Becquerel’s first studies were in mineralogy, and in association with Alexandre Brongniart, whose disciple he was, he discovered in 1819 a collection of important recent deposits at Auteuil that contained previously unknown crystalline forms of calcium phosphate.

associate:

Michael Faraday

Becquerel corresponded with Michael Faraday over diamagnetism; he had noticed examples of it before Faraday but had failed to generalize from them.

colleague:

Andre Ampere

colleague:

Jean-Baptiste Biot

References

• Dictionary of Scientific Biography
  1970