Jean-Marie Constant Duhamel (; ; 5 February 1797 – 29 April 1872) was a French

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

and

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

. His studies were affected by the troubles of the

Napoleonic era The Napoleonic era is a period in the history of France and Europe. It is generally classified as including the fourth and final stage of the French Revolution, the first being the National Assembly, the second being the Legislative ...

. He went on to form his own school ''École Sainte-Barbe''.

Duhamel's principle In mathematics, and more specifically in partial differential equations, Duhamel's principle is a general method for obtaining solutions to homogeneous differential equation, inhomogeneous linear evolution equations like the heat equation, wave equa ...

, a method of obtaining solutions to inhomogeneous linear evolution equations, is named after him. He was primarily a mathematician but did studies on the mathematics of

heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...

mechanics Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects r ...

, and

acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician ...

. He also did work in calculus using infinitesimals. Duhamel's theorem for infinitesimals says that the sum of a series of infinitesimals is unchanged by replacing the infinitesimal with its principal part. In 1843 he published about an early recording device he called a

vibroscope Vibroscope ( la, vibrare 'vibrate' + scope) is an instrument for observing and tracing (and sometimes recording) vibration. For example, a primitive mechanical vibroscope consists of a vibrating object with a pointy end which leaves a wave trace ...

. Like other similar devices, the vibroscope was a type of measuring device similar to an

oscilloscope An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetiti ...

, and could not play back the etchings it recorded.

Honours

* 19617 Duhamel,

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

named after him

References

19th-century French mathematicians French physicists Members of the French Academy of Sciences 1797 births 1872 deaths {{france-physicist-stub

Honours

See also

References