# 1911 Encyclopædia Britannica/Quetelet, Lambert Adolphe Jacques

**QUETELET, LAMBERT ADOLPHE JACQUES** (1796-1874),
Belgian astronomer, meteorologist and statistician, was born
at Ghent on the 22nd of February 1796, and educated at the
lyceum of that town. In 1819 he was appointed professor of
mathematics at the athenaeum of Brussels; in 1828 he became
lecturer at the newly created museum of science and literature,
and he continued to hold that post until the museum was
absorbed in the free university in 1834. In 1828 he was
appointed director of the new royal observatory which it had
been decided to found, chiefly at his instigation. The building
was finished in 1832, and the instruments were ready for work
in 1835, from which date the observations were published in
4to volumes (*Annales de l'Observatoire Royal de Bruxelles*),
but Quetelet chiefly devoted himself to meteorology and
statistics. From 1834 he was perpetual secretary of the
Brussels Academy, and published a vast number of articles
in its *Bulletin*, as also in his journal, *Correspondence mathématique*
*et physique* (11 vols., 1825-39). He died at Brussels on the 17th of February 1874. His son, Ernest Quetelet (1825-78),
was from 1856 attached to the observatory, and on his death
succeeded him as director. He made a great number of
observations of stars with proper motion.

Quetelet's astronomical papers refer chiefly to shooting stars
and similar phenomena. He organised extensive magnetical and
meteorological observations, and in 1839 he started regular
observations of the periodical phenomena of vegetation, especially the
flowering of plants. The results are given in various memoirs
published by the Brussels Academy, and in his works *Sur le climat*
*de la Belgique* and *Sur la physique du globe* (the latter forms vol.
xiii. of the Annales, 1861). He is, however, chiefly known by the
statistical investigations which occupied him from 1823 onward.
In 1835 he published his principal work, *Sur l'hornme et le développement*
*de ses facultés, ou essai de physique sociale* (2nd ed., 1869),
containing a résumé of his statistical researches on the development
of the physical and intellectual qualities of man, and on the
“average man” both physically and intellectually considered. In
1846 he brought out his *Lettres à S. A. R. le duc régnant de*
*Saxe-Coburg et Gotha sur la théorie des probabilités appliquée aux sciences*
*morales et politiques* (of which Sir J. Herschel wrote a full account
in the *Edinburgh Review*), and in 1848 *Du système social et des lois*
*qui le régissent*. In these works he shows how the numbers
representing the individual qualities of man are grouped round the
numbers referring to the “average man” in a manner exactly
corresponding to that in which single results of observation are
grouped round the mean result, so that the principles of the theory
of probabilities may be applied to statistical researches on the
subjects. These ideas are further developed in various papers in
the *Bulletin* and in his *L'Anthropométrie, ou mesure des différentes*
*facultés de l'homme* (1871), in which he lays great stress on the
universal applicability of the binomial law,—according to which the
number of cases in which, for instance, a certain height occurs
among a large number of individuals is represented by an ordinate
of a curve the binomial) symmetrically situated with regard to
the ordinate representing the mean result (average height). A
detailed *Essai sur la 'vie et les travaux de L. A. J. Quetelet*, by his
pupil and assistant E. Mailly, was published at Brussels in 1875.