Gramont, Antoine Alfred Arnaud Xavier Louis De

(b. Paris, France, 21 April 1861; d. Savenniêres, Maine-et-Loire, France, 31 October 1923)

physics, mineralogy.

Gramont belonged to an aristocratic family and was able to devote himself to scientific research without regard for financial concerns. His first studies, in organic synthesis, were followed by the artificial production of several minerals, including boracite and datholite. He also investigated, in collaboration with Georges Friedel, the pyroelectricity of scolecite.

Beginning in 1894 Gramont specialized in spectroscopy, a field to which he soon contributed new methods. He found that the electric spark of a condenser that is constantly recharged by means of an induction coil (condensed spark) is brighter, shorter, and wider than the spark from a simple coil. In producing the spark on the surface of the a compound, Gramont observed a complex spectrum in which each constituent element of the compound, upon being discharged, yielded its own spectrum independently. He termed this spectrum, resulting from the simple superposition of the line spectra of elements composing a body, the “dissociation spectrum.”

By suppressing the condenser, Gramont eliminated the spectra of the metalloids and was left with the lines of the metals. At first he confined his studies to the visible portion of the spectrum, but it was obvious that such a technique could constitute a general method of investigation. Through the use of photography it could be extended to the portion of the ultraviolet that passes through the air.

For some twenty years Gramont perfected his method and broadened its field of application. About 1902, with Watteville and Hemsalech, he examined the effect of placing a self-induction coil in the discharge circuit: the result was a weakening of the high-temperature lines and a strengthening of the low-temperature lines. Enlarging the self-induction coil eliminated the lines of the air and then of the metalloids. In order to study the spark spectrum of liquids without interference from lines produced by the electrodes, Gramont generated the spark between the drops forming at the extremities of two capillary tubes (1907). He observed nonconducting substances in the form of solutions in fused salts. At about this same time he discovered the ultimate lines. If a substance is examined in increasingly smaller amounts, the lines likewise become steadily weaker, but their decrease is very irregular: the last visible lines are not the most intense ones of the ordinary spectrum. This discovery facilitated research on traces in general and also, to a degree, opened up the possibilities of quantitative analysis with the spectroscope. Gramont himself obtained some interesting results in this manner.

Gramont died very suddenly, shortly after he had finished correcting the proofs of a major work on spectroscopy written in collaboration with P. E. L. de Boisbaudran, whose career was somewhat similar to his own.

BIBLIOGRAPHY

I. Original Works. From 1890 to 1921 Gramont published more than 100 communications to the Académie des Sciences in Comptes rendus hebdomadaires des séances de l’Académie des sciences, 110–173 . His last work was Analyse spectrale appliquée à l’analyse chimique (Paris. 1923), written with P. E. L. de Boisbaudran; Gramont was responsible for pt. 2. See also his Notice sommtaire sur les travaux scientifiques de M. A. de Gramont (Paris. 1910).

II. Sondary Literature. See Edouard Branly, Rapport sur les travaux de M. A. de Gramont (Paris, 1913); Chrles Fabry, “Arnaud de Gramont (1861–1923),” in Revue d’optique théorique el instrumentale, 3 (1924), 153–156; and Albin Haller, “Notice biographique sur Arnaud de Gramont,” in Comptes rendus hebdomadaires des séances de l’ Académie des sciences, 180 (1925), 106–107.

J. Payen