Achille Ernest Oscar Joseph Delesse (3 February 181724 March 1881) was a French
geologist
A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...
and
mineralogist
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...
. He is credited for inventing the
Delesse principle in
stereology
Stereology is the three-dimensional interpretation of two-dimensional cross sections of materials or tissues. It provides practical techniques for extracting quantitative information about a three-dimensional material from measurements made on two ...
.
Education and career
Delesse was born at
Metz
Metz ( , , , then ) is a city in northeast France located at the confluence of the Moselle (river), Moselle and the Seille (Moselle), Seille rivers. Metz is the Prefectures in France, prefecture of the Moselle (department), Moselle Departments ...
. At the age of twenty he entered the
École polytechnique
(, ; also known as Polytechnique or l'X ) is a ''grande Ă©cole'' located in Palaiseau, France. It specializes in science and engineering and is a founding member of the Polytechnic Institute of Paris.
The school was founded in 1794 by mat ...
, and subsequently went to the
Ecole des Mines, where he was trained under the tutelage of
Jean-Baptiste Élie de Beaumont and
Ours-Pierre-Armand Petit-Dufrénoy
Ours-Pierre-Armand Petit-Dufrénoy (5 September 1792 – 20 March 1857) was a French geologist and mineralogist.
Education and career
He was born at Sevran, in the ''département'' of Seine-et-Oise. After leaving the Imperial Lyceum in 1811, he ...
. In 1845, he was appointed to the chair of
mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...
and
geology
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...
at the
University of Franche-Comté
The Marie and Louis Pasteur University (UMLP), formerly known as University of Franche-Comté, is a pluridisciplinary public French university located in Besançon, Franche-Comté, with decentralized campuses in Belfort, Montbéliard, Vesoul and ...
in
Besançon
Besançon (, ; , ; archaic ; ) is the capital of the Departments of France, department of Doubs in the region of Bourgogne-Franche-Comté. The city is located in Eastern France, close to the Jura Mountains and the border with Switzerland.
Capi ...
. In 1850, he became the chair of geology at the
Sorbonne in
Paris
Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...
; and in 1864, professor of
agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
at the Ecole des Mines.
Delesse died in Paris on 24 March 1881.
Research
In early years as ''ingénieur des mines'', Delesse investigated and described various new
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
s; he proceeded afterward to the study of
rock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wale ...
s, devising new methods for their determination, and giving particular descriptions of
melaphyre,
arkose
Arkose () or arkosic sandstone is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar.
Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Components
...
,
porphyry,
syenite
Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a igneous rock
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
s of the
Vosges
The Vosges ( , ; ; Franconian and ) is a range of medium mountains in Eastern France, near its border with Germany. Together with the Palatine Forest to the north on the German side of the border, they form a single geomorphological unit and ...
, and those of the
Alps
The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.
...
,
Corsica
Corsica ( , , ; ; ) is an island in the Mediterranean Sea and one of the Regions of France, 18 regions of France. It is the List of islands in the Mediterranean#By area, fourth-largest island in the Mediterranean and lies southeast of the Metro ...
, etc., and the subject of
metamorphism
Metamorphism is the transformation of existing Rock (geology), rock (the protolith) to rock with a different mineral composition or Texture (geology), texture. Metamorphism takes place at temperatures in excess of , and often also at elevated ...
occupied his attention. He also prepared in 1858 geological and hydrological maps of Paris, with reference to the underground water, similar maps of the ''
département
In the administrative divisions of France, the department (, ) is one of the three levels of government under the national level (" territorial collectivities"), between the administrative regions and the communes. There are a total of 101 ...
s'' of the
Seine
The Seine ( , ) is a river in northern France. Its drainage basin is in the Paris Basin (a geological relative lowland) covering most of northern France. It rises at Source-Seine, northwest of Dijon in northeastern France in the Langres plat ...
and
Seine-et-Marne
Seine-et-Marne () is a department in the ĂŽle-de-France region in Northern France. Named after the rivers Seine and Marne, it is the region's largest department with an area of 5,915 square kilometres (2,284 square miles); it roughly covers its ...
, and an agronomic map of the Seine-et-Marne (1880), in which he showed the relation that exists between the physical and chemical characters of the
soil
Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
and the geological structure.
The annual ''Revue des progrès de géologie'' of Delesse, undertaken with the assistance (1860–1865) of
Auguste Laugel and afterwards (1865–1878) of
Albert de Lapparent
Albert Auguste Cochon de Lapparent (30 December 18395 May 1908) was a French geologist.
Life
He was born at Bourges. After studying at the École polytechnique from 1858 to 1860 he became ''ingénieur au corps des mines'', and took part in drawi ...
, was carried on from 1860 to 1880. His observations on the
lithology
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...
of the deposits accumulated beneath the sea were of special interest and importance. His separate publications were: ''Recherches sur l'origine des roches'' (Paris, 1865); ''Étude sur le métamorphisme des roches'' (1869), ''Lithologie des mers de France et des mers principales du globe'' (2 vols. and atlas, 1871).
Honors
Delesse was elected as a member to the
American Philosophical Society
The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
in 1863, and to the
French Academy of Sciences
The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...
in 1879.
In 1878, he became inspector-general of the
Corps des mines
The () is the foremost technical Grand Corps of the French State (). It is composed of the state industrial engineers. The Corps is attached to the French Ministry of Economy and Finance. Its purpose is to entice French students in mathematic ...
.
References
{{DEFAULTSORT:Delesse, Achille
French geologists
French mineralogists
Members of the French Academy of Sciences
1817 births
1881 deaths
Academic staff of the University of Paris
École Polytechnique alumni
People from Metz
Mines Paris - PSL alumni
University of Franche-Comté people
International members of the American Philosophical Society