"Modern Science" Part 2 of 3 (b. 1700-1799)

In case you don't recognize him, Ben Franklin has a bit of a jazzed up countenance when it comes to science! Perhaps some will remember the musical "1776" which came out, more-or-less (well, 1969, to be exact) for the U.S. the bicentenail. Ben played a spritely old chap in that one too. (Ralph Archbold, pictured, is one of the more noted Ben portrayers).

It turns out ole' Ben really WAS a polymath. Not quite the mathematical theoritician of some of his 17th century contemporaries, but on the other hand, I don't think any of them would want to cross wits with him. And it seems his scientific accomplishments (substantially) exceed his pop-culture reputation- which I suppose have been somewhat simplified for mass consumption. He was also quite a political theorist and statesmen, somewhat less understated by contemporary accounts.
This week's headline covers what I thought were some of the most significant scientists/physicits/mathematicians who were born in the 1700's- their work spanning into the first part of the 1800's in some cases. There were many others in this time frame- this is my best stab at a "conscice" listing. (Sorry I didn't do a very good job at that- believe me, it was HARD to thin it down to this even). I picked those who I though advanced the theory and art of science related to our present aviation technologies. (If I missed one of your fav's, please give 'em there due and post a bit about them).

Interestingly, Fellows of the Royal Society (F.R.S.) seemed to dominate the first part of this listing (and the last part of the previous list), but the French Academy of Science more dominates the later part of this list. Exciting times, both politically and scientifically, in this period (approx. 1720-1850).

1701 Celsius (27 November 1701 – 25 April 1744)
1706 Ben Franklin (January 17, 1706 – April 17, 1790)
1707 Euler (15 April 1707 – 18 September 1783)
1717 d'Alembert (16 November 1717 – 29 October 1783)
1736 Watt (19 January 1736 – 25 August 1819)
1736 Lagrange (25 January 1736 – 10 April 1813)
1736 Coulomb (14 June 1736 – 23 August 1806)
1737 Galvani (September 9, 1737 – December 4, 1798)
1745 Volta (February 18, 1745 – March 5, 1827)
1752 Legendre (18 September 1752 – 10 January 1833)
1764 Charles (12 November, 1746– 7 April, 1823)
1766 Dalton (6 September 1766 – 27 July 1844)
1768 Fourier (21 March 1768 – 16 May 1830)
1773 Young (13 June 1773 – 10 May 1829)
1773 Cayley (27 December 1773 – 15 December 1857)
1774 Biot (21 April 1774 – 3 February 1862)
1775 Ampere (20 January 1775 – 10 June 1836)
1777 Gauss (30 April 1777 – 23 February 1855)
1777 Oersted (14 August 1777 - 9 March 1851)
1778 Gay-Lussac (6 December 1778 – 9 May 1850)
1781 Poisson (21 June 1781 – 25 April 1840)
1785 Navier (10 February 1785 – 21 August 1836)
1788 Fresnel (10 May 1788 – 14 July 1827)
1789 Ohm (16 March 1789 – 6 July 1854)
1789 Cauchy (21 August 1789 – 23 May 1857)
1791 Savart (June 30, 1791 – March 16, 1841
1791 Faraday (22 September 1791 – 25 August 1867)
1792 Coriolis (21 May 1792 – 19 September 1843)
1799 Clapeyron (26 February 1799 – 28 January 1864)

Synopsis of contributions:
1701 Celsius (27 November 1701 – 25 April 1744)
"Swedish astronomer. He was professor of astronomy at Uppsala University from 1730 to 1744, but traveled from 1732 to 1735 visiting notable observatories in Germany, Italy and France...In 1736, he participated in the expedition...to measure a degree of latitude. The aim of the expedition was to measure the length of a degree along a meridian, close to the pole, and compare the result with a similar expedition to Peru, today in Ecuador near the equator. The expeditions confirmed Issac Newton's belief that the shape of the earth is an ellipsoid flattened at the poles....
In astronomy, Celsius began a series of observations using colored glass plates to record the magnitude (a measure of brightness) of certain stars. This was the first attempt to measure the intensity of starlight with a tool other than the human eye.
In 1742 he proposed the Celsius temperature scale which takes his name."

1706 Ben Franklin (January 17, 1706 – April 17, 1790)
"Born in Boston...was one of the Founding Fathers of the United States of America. A noted polymath, Franklin was a leading author and printer, satirist, political theorist, politician, scientist, inventor, civic activist, statesman, soldier, and diplomat. As a scientist, he was a major figure in the Enlightenment and the history of physics for his discoveries and theories regarding electricity. He invented the lightning rod, bifocals, the Franklin stove, a carriage odometer...He formed both the first public lending library in America and the first fire department in Pennsylvania. He was an early proponent of colonial unity, and as a political writer and activist, he supported the idea of an American nation. As a diplomat during the American Revolution, he secured the French alliance that helped to make independence of the United States possible. Franklin is credited as being foundational to the roots of American values and character, a marriage of the practical and democratic Puritan values of thrift, hard work, education, community spirit, self-governing institutions, and opposition to authoritarianism both political and religious, with the scientific and tolerant values of the Enlightenment. In the words of Henry Steele Commager, "In Franklin could be merged the virtues of Puritanism without its defects, the illumination of the Enlightenment without its heat." To Walter Isaacson, this makes Franklin, "the most accomplished American of his age and the most influential in inventing the type of society America would become."
In recognition of his work with electricity, Franklin received the (British) Royal Society's Copley Medal in 1753, and in 1756 he became one of the few eighteenth century Americans to be elected as a Fellow of the Society...Franklin was, along with his contemporary Leonard Euler, the only major scientist who supported Christiaan Huygen's wave theory of light, basically ignored by the rest of the scientific community. (...Only after the famous Young's slit experiment were most of the scientists persuaded to believe Huygens' theory)...He deduced that storms do not always travel in the direction of the prevailing wind, a concept which would have great influence in meterology...Franklin noted a principle of refigeration by observing that on a very hot day, he stayed cooler in a wet shirt in a breeze than he did in a dry one. To understand this phenomenon more clearly Franklin conducted experiments...According to Michael Faraday, Franklin's experiments on the non-conduction of ice are worth mentioning...
An aging Franklin accumulated all his Oceanographic findings in Maritime Observations, published by the Philosophical Society's transactions in 1786. It contained ideas for sea anchors, catamaran hulls, watertight compartments, shipboard lighting rods, and a soup bowl designed to stay stable in stormy weather"

1707 Euler (15 April 1707 – 18 September 1783)
"a pioneering Swiss mathematician and physicist...Euler made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function. He is also renowned for his work in mechanics, fluid dynamics, optics, and astronomy. Euler is considered to be the preeminent mathematician of the 18th century and one of the greatest of all time. He is also one of the most prolific; his collected works fill 60–80 volumes. A statement attributed to Pierre-Simon Laplace expresses Euler's influence on mathematics: "Read Euler, read Euler, he is the master of us all."
Euler was born in Basel to Paul Euler, a pastor a pastor and a friend of the Bernoulli family- Johann Bernoulli, who was then regarded as Europe's foremost mathematician, would eventually be the most important influence on young Leonhard Euler's early formal education. Euler introduced the concept of a function and was the first to write f(x) to denote the function f applied to the argument x. He also introduced the modern notation for the trigonometric functions, the letter "e" for the base of the natural logarithm (now also known as Euler's number), the Greek letter sigma for summations and the letter "i" to denote the imaginary unit. Euler is well-known in analysis for his frequent use and development of power series, the expression of functions as sums of infinitely many terms...Euler introduced the use of the exponential function and logarithms in analytic proofs. He discovered ways to express various logarithmic functions using power series, and he successfully defined logarithms for negative and complex numbers, thus greatly expanding the scope of mathematical applications of logarithms. He also defined the exponential function for complex numbers, and discovered its relation to the trigonometric functions- a special case...is known as Euler's identity... was called "the most remarkable formula in mathematics" by Richard Feynman. In 1988, readers of the Mathematical Intelligencer voted it "the Most Beautiful Mathematical Formula Ever" (for its single uses of the notions of addition, multiplication, exponentiation, and equality, and the single uses of the important constants 0, 1, "e", "i", and pi). In total, Euler was responsible for three of the top five formulae in that poll. De Moivre's formula is a direct consequence of Euler's formula.
In addition, Euler elaborated the theory of higher transcendental functions by introducing the gamma function and introduced a new method for solving quatric equations. He also found a way to calculate integrals with complex limits, foreshadowing the development of modern complex analysis, and inventing the calculus of variations including its best-known result, the Euler-Lagrange equation. Euler also pioneered the use of analytic methods to solve number theory problems. In doing so, he united two disparate branches of mathematics and introduced a new field of study, analytic number theory. In breaking ground for this new field, Euler created the theory of hypergeometric series, q-series, hyperbolic trigonometric functions and the analytic theory of continued fractions. For example, he proved the infinitude of primes using the divergence of the harmonic series, and he used analytic methods to gain some understanding of the way prime numbers are distributed. Euler's work in this area led to the development of the prime number theorem...his ideas paved the way for the work of Carl Friedrich Gauss."

1717 d'Alembert (16 November 1717 – 29 October 1783)
"a French mathematican, mechanician, physicst and philosopher. D'Alembert's method for the wave equation is named after him. ("The wave equation is an important second-order linear partial differential equation of waves, such as sound waves, light waves, and water waves. It arises in fields such as acoustics, electromagnetics, and fluid dynamics. Historically, the problem of a vibrating string such as that of a musical instrument was studied by Jean le Rond d'Alembert, Leonhard Euler, Daniel Bernoulli, and Joseph-Louis Legrange"). He entered law school for two years, and was nominated avocat in 1738. He was also interested in medicine and mathematics...D'Alembert was also a Latin scholar of some note and worked in the latter part of his life on a superb translation of Tacitus, from which he received wide praise. In 1740, he submitted his second scientific work from the field of fluid mechanics...In this work d'Alembert theoretically explained refraction...In 1743 he published his most famous work, "Traite de dynamique", in which he developed his own laws of motion.
When the "Encyclopédie" was organized in the late 1740s, d'Alembert was engaged as co-editor (for mathematics and science) with Diderot, and served until a series of crises temporarily interrupted the publication in 1757. He authored over a thousand articles for it, including the famous "Preliminary Discourse". D'Alembert "abandoned the foundation of Materialism, and anticipated the Transcendental idealism of Kant. In 1752, he wrote about what is now called D'Alembert's paradox: that the drag on a body immersed in an inviscid, incompressible fluid is zero. In France, the fundamental theorem of algebra is known as the d'Alembert/Gauss theorem. He also created his ratio test, a test to see if a series converges. The D'Alembertian operator, which first arose in D'Alembert's analysis of vibrating strings, plays an important role in modern theoretical physics."

1736 Watt (19 January 1736 – 25 August 1819)
"was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution. Watt was an enthusiastic inventor, with a fertile imagination that sometimes got in the way of finishing his works, because he could always see "just one more improvement". He was skilled with his hands, and was also able to perform systematic scientific measurements that could quantify the improvements he made and produce a greater understanding of the phenomenon he was working with. Watt was a gentleman, greatly respected by other prominent men of the Industrial Revolution. He was an important member of the Lunar Society, and was a much sought after conversationalist and companion, always interested in expanding his horizons. He was a rather poor businessman, and especially hated bargaining and negotiating terms with those who sought to utilize the steam engine. Until he retired, he was always much concerned about his financial affairs, and was something of a worrier. His personal relationships with his friends and partners were always congenial and long-lasting.
Watt had never seen an operating steam engine, but he tried constructing a model. It failed to work satisfactorily, but he continued his experiments and began to read everything he could about the subject. He independently discovered the importance of latent heat in understanding the engine, which, unknown to him, Black had famously discovered some years before...after much experimentation he showed that about 80% of the heat of the steam was consumed in heating the cylinder, because the steam in it was condensed by an injected stream of cold water. His critical insight was to cause the steam to condense in a separate chamber apart from the piston, and to maintain the temperature of the cylinder at the same temperature as the injected steam. He soon had a working model by 1765.
Over the next six years, he made a number of other improvements and modifications to the steam engine. A double acting engine, in which the steam acted alternately on the two sides of the piston was one. He described methods for working the steam expansively. A compound engine, which connected two or more engines was described. Two more patents were granted for these in 1781 and 1782. Numerous other improvements that made for easier manufacture and installation were continually implemented. One of these included the use of the steam indicator which produced an informative plot of the pressure in the cylinder against its volume, which he kept as a trade secret. Another important invention, one of which Watt was most proud of, was the Parallel motion / three-bar linkage which was especially important in double-acting engines as it produced the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a circular arc. This was patented in 1784. A throttle valve to control the power of the engine, and a centrifugal governor, patented in 1788, to keep it from "running away" were very important. These improvements taken together produced an engine which was up to five times as efficient in its use of fuel as the Newcomen engine. Because of the danger of exploding boilers and the ongoing issues with leaks, Watt was opposed from the first to the use of high pressure steam – all of his engines used steam at very low pressure.
He was one of only eight Foreign Associates of the French Academy of Science. The watt is named after James Watt for his contributions to the development of the steam engine, an d was adopted by the Second Congress of the British Association for the Advancement of Science in 1889 and...in 1960 as the unit of power incorporated in the International System of Units (or "SI")."

1736 Lagrange (25 January 1736 – 10 April 1813)
"was an Italian-born mathematician and astronomer, who lived part of his life in Prussia and part in France, making significant contributions to all fields of analysis, to number theory, and to classical and celestial mechanics. On the recommendation of Euler and D'Alembert, in 1766 Lagrange succeeded Euler as the director of mathematics at the Prussian Academy of Sciences in Berlin, where he stayed for over twenty years, producing a large body of work and winning several prizes of the French Academy of Sciences. Lagrange's treatise on analytical mechanics, written in Berlin and first published in 1788, offered the most comprehensive treatment of classical mechanics since Newton and formed a basis for the development of mathematical physics in the nineteenth century.
Lagrange was one of the creators of the calculus of variations...He also extended the method to take into account possible constraints, arriving at the method of Lagrange multipliers. Lagrange invented the method of solving differential equations known as variation of parameters, applied differential calculus to the theory of probabilities, and attained notable work on the solution of equations. His treatise "Theorie des fonctions analytiques" laid some of the foundations of group theory, anticipating Galois. In calculus, Lagrange developed a novel approach to interpolation and Taylor series. He studied the three-body problem for the Earth, Sun, and Moon (1764) and the movement of Jupiter’s satellites (1766). But above all he impressed on mechanics, having transformed Newtonian mechanics into a branch of analysis, Lagrangian mechanics as it is now called, and exhibited the so-called mechanical "principles" as simple results of the variational calculus. During the years from 1772 to 1785, he contributed a long series of papers which created the science of partial differential equations. A large part of these results were collected in the second edition of Euler's integral calculus which was published in 1794. He made contributions to the theory of continued fractions. Lagrange formulated his celebrated method of Lagrange multipliers, in the context of problems of variational calculus with integral constraints. These works devoted to differential calculus and calculus of variations may be considered as the starting point for the researches of Cauchy, Jacobi, and Weierstrass.
His "Resolution des equations numeriques", published in 1798, was also the fruit of his lectures at Ecole Polytechnique. There he gives the method of approximating to the real roots of an equation by means of continued fractions, and enunciates several other theorems. The theory of the palnetary motions had formed the subject of some of the most remarkable of Lagrange's Berlin papers. In 1806 the subject was reopened by Poisson, who, in a paper read before the French Academy, showed that Lagrange's formulae led to certain limits for the stability of the orbits. "

1736 Coulomb (14 June 1736 – 23 August 1806)
"was a French physicist. He is best known for developing Coulomb's law, the definition of the electrostatic force of attraction and repulsion. The SI unit of charge, the coulomb, was named after him.
Coloumb initially took part in the survey for the British coastal charts and was then sent on a mission to Martinique in 1764 to take part in the construction of the Fort Bourbon...Coulomb spent eight years directing the work, contracting tropical fever. He carried out several experiments on the resistance of masonries and the behavior of the walls of escarpe (supportings), which were inspired by the ideas of pieter van Musschenbroek on friction. Coulomb leaves a legacy as a pioneer in the field of geotechnical engineering for his contribution to retaining wall design.
He discovered an inverse relationship of the force between electric charges and the square of its distance, later named after him as Coulomb's law. His memoir contained the results of Coulomb's experiments on the torsional force for metal wires. It also contained a detailed description of different forms of his torsion balance. He used the instrument with great success for the experimental investigation of the distribution of charge on surfaces, of the laws of electrical and magnetic force and of the mathematical theory of which he may also be regarded as the founder."

1737 Galvani (September 9, 1737 – December 4, 1798)
"An Italian physician and physicist…in1771, he discovered that the muscles of dead frogs legs twitched when struck by a spark. The phenomenon was dubbed galvanism, after Galvani, on the suggestion of his peer and sometime intellectual adversary Alessandro Volta…This was one of the first forays into the study of bioelectricity, a field that still today studies the electrical patterns and signals of the nervous system…At first he thought about being a mechanic because he loved taking and dealing with spool testing. Later, his wish was to enter the church, but by his parents he was educated for a medical career. Galvani attended Bologna's medicine school and became a medical doctor like his father. At the University of Bologna, he was in 1762 appointed public lecturer in anatomy, and soon gained repute as a skilled though not eloquent teacher, and, chiefly from his researches on the organs of hearing and genito-urinary tract of birds, as a comparative anatomist.
(Volta, essentially, objected to Galvani’s conclusions about "animal electric fluid", but the two scientists disagreed respectfully and Volta coined the term "galvanism" for a direct current of electricity produced by chemical action. Thus, owing to an argument between the two in regard to the source or cause of the electricity, Volta built the first battery in order to specifically disprove his associate's theory. Volta's “pile” became known therefore as a voltaic pile)."

1745 Volta (February 18, 1745 – March 5, 1827)
"An Italian physicist known especially for the development of the first electric cell in 1800…In 1776-77 Volta studied the chemistry of gases, he discovered methane by collecting the gas from marshes. He devised experiments such as the ignition of methane by an electric spark in a closed vessel. Volta also studied what we now call electrical capacitance, developing separate means to study both electrical potential (V) and charge (Q), and discovering that for a given object they are proportional. This may be called Volta's Law of capacitance, and likely for this work the unit of electrical potential has been named the Volt.
Volta began to study, around 1791, the "animal electricity" noted by Luigi Galvani when two different metals were connected in series with the frog's leg and to one another. Volta realized that the frog's leg served as both a conductor of electricity (we would now call it an electrolyte) and as a detector of electricity. He replaced the frog's leg by brine-soaked paper, and detected the flow of electricity by other means familiar to him from his previous studies. In this way he discovered the electrochemical series, and the law that the electromotive force (emf) of a galvanic cell, consisting of a pair of metal electrodes separated by electrolyte, is the difference between their two electrode potentials.(Thus, two identical electrodes and a common electrolyte give zero net emf.) This may be called Volta's Law of the electrochemical series."

1752 Legendre (18 September 1752 – 10 January 1833)
"A French mathematician. He made important contributions to statistics, number theory, abstract algebra, and mathematical analysis. Most of his work was brought to perfection by others: his work on roots of polynomials inspired Galios theory; Abel’s work on elliptic functions was built on Legendre's; some of Gauss’ work in statistics and number theory completed that of Legendre. He developed the least squares method, which has broad application in linear regression, signal processing, statistics, and curve fitting. In 1830 he gave a proof of Fermat’s last theorem for exponent n = 5, which was also proven by Dirichlet in 1828.
In number theory, he conjectured the quadratic reciprocity law, subsequently proved by Gauss; in connection to this, the Legrendre symbol is named after him. He also did pioneering work on the distribution of primes, and on the application of analysis to number theory. His 1796 conjecture of the Prime number theorem was rigorously proved by Hadamard and de la Vallee-Poussin in 1898.
Legendre did an impressive amount of work on elliptic functions, including the classification of elliptic integrals, but it took Abel’s stroke of genius to study the inverses of Jacobi’s functions and solve the problem completely.
He is known for the Legendre transformation, which is used to go from the Lagrangian to the Hamiltonian formulation of classical mechanics. In thermodynamics it is also used to obtain the enthalpy and the Hemholtz and Gibbs (free) energies from the internal energy. He is also the namegiver of the Legendrea polynomials, solutions to Legendre's differential equation, which occur frequently in physics and engineering applications, e.g., electrostatics. Legendre is best known as the author of Élements de geometrie, which was published in 1794 and was the leading elementary text on the topic for around 100 years. This text greatly rearranged and simplified many of the propositions from Euclid’s Elements to create a more effective textbook.
Legendre is best known as the author of "Elements de geometrie", which was published in 1794 and was the leading elementary text on the topic for around 100 years. This text greatly rearranged and simplified many of the propositions from "Euclid's Elements" to create a more effective textbook."

1764 Charles (12 November, 1746– 7 April, 1823)
"French inventor, scientist, mathematician, and balloonist. Charles and the Robert brothers launched the world's first (unmanned) hydrogen-filled balloon in August 1783, then in December 1783, Charles and his co-pilot ascended to a height of about 1,800 feet (550 m) in a manned balloon. Their pioneering the use of hydrogen for lift led to this type of balloon being named a Charliere (as opposed to a Montgolfiere which used hot air). Charles's law, describing how gases tend to expand when heated, was credited unpublished work by Jacques Charles.
On December 1, 1783 Jacques Charles and the Robert brothers launched a new manned balloon from Paris. Jacques Charles was accompanied by Nicolas-Louis Robert as co-pilot of the 380-cubic-metre, hydrogen-filled balloon. The envelope was fitted with a hydrogen release valve and was covered with a net from which the basket was suspended. Sand ballast was used to control altitude. They ascended to a height of about 1,800 feet (550 m) and landed at sunset in Nesles-la-Vallee after a 2 hour 5 minute flight covering 36 km. The chasers on horseback, who were led by the Duc de Chartres, held down the craft while both Charles and Nicolas-Louis alighted. Jacques Charles then decided to ascend again, but alone this time because the balloon had lost some of its hydrogen. This time it ascended rapidly to an altitude of about 3,000 metres, where he saw the sun again. He began suffering from aching pain in his ears so he 'valved' to release gas, and descended to land gently about 3 km away at tour du Lay. Unlike the Robert brothers, Charles never flew again although a hydrogen balloon came to be called a "Charliere" in his honour.
It is reported that 400,000 spectators witnessed the the launch, and that hundreds had paid one crown each to help finance the construction and receive access to a 'special enclosure' for a "close-up view" of the take-off. Among the 'special enclosure' crowd was Benjamin Franklin, the diplomatic representative of the United States of America. Also present was Joseph Montgolfier, whom Charles honoured by asking him to release the small, bright green, pilot balloon to assess the wind and weather conditions.
This event took place ten days after the world's first manned balloon flight by jean-Francois Pilatre de Rozier using a Montolfier brothers hot air balloon. "

1766 Dalton (6 September 1766 – 27 July 1844)
"an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory, and his research into colour blindness (sometimes referred to as Daltonism, in his honour).
Around 1790 Dalton seems to have considered taking up law or medicine, but his projects were not met with encouragement from his relatives...Mainly through John Gough, a blind philosopher and polymath from whose informal instruction he owed much of his scientific knowledge.
Dalton's early life was highly influenced by a prominent Eaglesfield Quaker named Elihu Robinson, a competent meteorologist and instrument maker, who got him interested in problems of mathematics and meterology...in 1787 he began to keep a meterological diary in which, during the succeeding 57 years, he entered more than 200,000 observations. He also rediscovered George Hadley's theory of atmospheric circulation (now known as the Hadley cell) around this time. Dalton's first publication was "Meteorological Observations and Essays" (1793), which contained the seeds of several of his later discoveries. However, in spite of the originality of his treatment, little attention was paid to them by other scholars. A second work by Dalton, "Elements of English Grammar", was published in 1801...This paper was followed by many others on diverse topics on rain and dew and the origin of springs, on heat, the colour of the sky, steam, the auxiliary verbs and participles of the English language and the reflection and refraction of light.
In 1800, Dalton became a secretary of the Manchester Literary and Philosophical Society, and in the following year he orally presented an important series of papers, entitled "Experimental Essays" on the constitution of mixed gases, on the pressure of steam and other vapours at different temperatures, both in a vacuum and in air; on evaporation; and on the thermal expansion of gases.
The most important of all Dalton's investigations are those concerned with the atomic theory in chemistry, with which his name is inseparably associated...Dalton proceeded to print his first published table of relative atomic weights. Six elements appear in this table, namely hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus, with the atom of hydrogen conventionally assumed to weigh 1...It appears, then, that confronted with the problem of calculating the relative diameter of the atoms of which, he was convinced, all gases were made, he used the results of chemical analysis. Assisted by the assumption that combination always takes place in the simplest possible way, he thus arrived at the idea that chemical combination takes place between particles of different weights, and it was this which differentiated his theory from the historic speculations of the Greeks...The extension of this idea to substances in general necessarily led him to the law of multiple proportions, and the comparison with experiment brilliantly confirmed his deduction."

1768 Fourier (21 March 1768 – 16 May 1830)
"a French mathematician and physicist best known for initiating the investigation of Fourier series and their application to problems of heat transfer. The Fourier transform and Fourier's Law are also named in his honour. Fourier is also generally credited with the discovery of the greenhouse effect.
Fourier went with Napoleon Bonaparte on his Egyptian expedition in 1798, and was made governor of lower Egypt and secretary of the Institute d'Egypte. Cut off from France by the English fleet, he organized the workshops on which the French army had to rely for their munitions of war...in 1801, Fourier returned to France, and was made prefect of Isere, and it was while there that he made his experiments on the propagation of heat. Fourier moved to England in 1816. Later he returned to France, and in 1822 succeeded Jean Baptiste Joseph Delambre as Permanent Secretary of the French Academy of Sciences. In 1830, he was elected a foreign member of the Royal Swedish Academy of Sciences. In 1822 he published his Theorie analytique de la chaleur...in this work he claims that any function of a variable, whether continuous or discontinuous, can be expanded in a series of sines of multiples of the variable. Though this result is not correct, Fourier's observation that some discontinuous functions are the sum of infinite series was a breakthrough. The question of determining when a Fourier series converges has been fundamental for centuries. Fourier also developed dimensional analysis, the method of representing physical units, such as velocity and acceleration, by their fundamental dimensions of mass, time, and length, to obtain relations between them.
Fourier is also credited with the discovery in 1824 that gases in the atmosphere might increase the surface temperature of the Earth. This was the effect that would later be called the greenhouse effect. He described the phenomenon in 1824 and then again in a very similar paper in 1827 whereby an atmosphere serves to warm a planet. This established the concept of planetary energy balance - that planets obtain energy from a number of sources that cause temperature increase. "

1773 Young (13 June 1773 – 10 May 1829)
"an English genius and polymath, admired by among others Herschel and Einstein. He is famous with the public for having partly deciphered Egyptian hieroglyphs before Champollion did. Young made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony and Egyptology.

At the age of fourteen Young had learned Greek and Latin and was acquainted with French, Italian, Hebrew, German, Chaldean, Syriac, Samaritan, Arabic, Persian, Turkish and Amhairic. Young began to study medicine in London in 1792, moved to Edinburgh in 1794, and a year later went to Gottingen, Lower Saxony, Germany where he obtained the degree of doctor of physics in 1796. Young published many of his first academic articles anonymously to protect his reputation as a physician. In 1801 Young was appointed professor of natural philosophy (mainly physics) at the Ryoal Institution. In two years he delivered 91 lectures. In 1802, he was appointed foreign secretary of the Royal Society, of which he had been elected a fellow in 1794. He resigned his professorship in 1803, fearing that its duties would interfere with his medical practice. His lectures were published in 1807 in the "Course of Lectures on Natural Philosophy" and contain a number of anticipations of later theories.
In 1811 Young became physician to St. George's Hospital, and in 1814 he served on a committee appointed to consider the dangers involved in the general introduction of gas into London. In 1816 he was secretary of a commission charged with ascertaining the precise length of the seconds pendulum (the length of a pendulum whose period is exactly 2 seconds), and in 1818 he became secretary to the Board of Longitude and superintendent of the HM Nautical Almanac Office.
A few years before his death he became interested in life insurance, and in 1827 he was chosen one of the eight foreign associates of the French Academy of Sciences. In 1828, he was elected a foreign member of the Royal Swedish Academy of Sciences.
Later scholars and scientists have praised Young's work although they may know him only through achievements he made in their fields. His contemporary Sir John Herschel called him a "truly original genius". Albert Einstein praised him in the 1931 foreword to an edition of Newton's "Opticks". Other admirers include physicist Lord Rayleigh and Nobel laureate Philip Anderson. One of Thomas Young's direct descendants was Professor John Z. Yougn, M.A., F.R.S. (1907–1997), English zoologist and neurophysiologist.

In Young's own judgment, of his many achievements the most important was to establish the wave theory of light. To do so, he had to overcome the century-old view, expressed in the venerable Isaac Newton's "Optics", that light is a particle. Nevertheless, in the early 1800s Young put forth a number of theoretical reasons supporting the wave theory of light, and he developed two enduring demonstrations to support this viewpoint. With the ripple tank he demonstrated the idea of interference in the context of water waves. With the two-slit, or double-slit experiment, he demonstrated interference in the context of light as a wave. Young performed and analyzed a number of experiments, including interference of light from reflection off nearby pairs of micrometer grooves, from reflection off thin films of soap and oil, and from Newton's rings. He also performed two important diffraction experiments using fibers and long narrow strips. Within ten years, much of Young's work was reproduced and then extended by Fresnel.
Young described the characterization of elasticity that came to be known as Young's Modulus, denoted as E, in 1807, and further described it in his subsequent works such as his 1845 "Course of Lectures on Natural Philosophy and the Mechanical Arts". However, the first use of the concept of Young's modulus in experiments was by Giodano Riccati in 1782 – predating Young by 25 years. Furthermore, the idea can be traced back to a paper by Leonhard Euler published in 1727, some 80 years before Thomas Young's 1807 paper.
The Young's modulus relates the stress (pressure) in a body to its associated strain (change in length as a ratio of the original length); that is, stress = E × strain, for a uniaxially loaded specimen. Young's modulus is independent of the component under investigation; that is, it is an inherent material property (the term modulus refers to an inherent material property). Young's Modulus allowed, for the first time, prediction of the strain in a component subject to a known stress (and vice versa). Prior to Young's contribution, engineers were required to apply Hooke's F = kx relationship to identify the deformation (x) of a body subject to a known load (F), where the constant (k) is a function of both the geometry and material under consideration. Finding k required physical testing for any new component, as the F = kx relationship is a function of both geometry and material. Young's Modulus depends only on the material, not its geometry, thus allowing a revolution in engineering strategies.
Young has also been called the founder of physiological optics. In 1793 he explained the mode in which the eye accommodates itself to vision at different distances as depending on change of the curvature of the crystalline lens, in 1801 he was the first to describe astigmatism; and in his Lectures he presented the hypothesis, afterwards developed by Hemann von Helmholtz, that color perception depends on the presence in the retina of three kinds of nerve fibers which respond respectively to red, green and violet light. This foreshadowed the modern understanding of color vision, in particular the finding that the eye does indeed have three color receptors which are sensitive to different wavelength ranges.
In 1804, Young developed the theory of capillary phenomena on the principle of surface tension. He also observed the constancy of the angle of contact of a liquid surface with a solid, and showed how from these two principles to deduce the phenomena of capillary action. In 1805 Simon-Pierre Laplace, the French philosopher, discovered the significance of meniscus radii with respect to capillary action. In 1830 Carl Friedrich Gauss, the German mathematician, unified the work of these two scientists to derive the Young-Laplace equation, the formula that describes the capillary pressure difference sustained across the interface between two static fluids. Young was the first to define the term "energy" in the modern sense. Young’s equation describes the contact angle of a liquid drop on a plane solid surface as a function of the surface free energy, the interfacial free energy and the surface tension of the liquid. Young’s equation was developed further some 60 years later by Dupré to account for thermodynamic effects, and this is known as the Young–Dupré equation.
In physiology Young made an important contribution to haemodynamics in the Croonian lecture for 1808 on the "Functions of the Heart and Arteries," and his medical writings included "An Introduction to Medical Literature", including a "System of Practical Nosology' (1813) and "A Practical and Historical Treatise on Consumptive Diseases" (1815). Young devised a rule of thumb for determining a child’s drug dosage. Young’s Rule states that the child dosage is equal to the adult dosage multiplied by the child’s age in years, divided by the sum of 12 plus the child’s age.
In an appendix to his Gottingen dissertation (1796) there are four pages added proposing a universal phonetic alphabet. It includes 16 "pure" vowel symbols, nasal vowels, various consonants, and examples of these, drawn primarily from French and English. In his "Encyclopedia Britannica" article "Languages", Young compared the grammar and vocabulary of 400 languages.
Young was also one of the first who tried to decipher Egyptian hieroglyphs,...By 1814 Young had completely translated the "enchorial" (demotic, in modern terms) text of the Rosetta Stone (he had a list with 86 demotic words), and then studied the hieroglyphic alphabet but initially failed to recognize that the demotic and hieroglyphic texts were paraphrases and not simple translations. Some of Young's conclusions appeared in the famous article "Egypt" he wrote for the 1818 edition of the Encyclopedia Britannica.
He developed the Young temperament, a method of tuning musical instruments."

1773 Cayley (27 December 1773 – 15 December 1857)
"a prolific English engineer, one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and first person to understand the underlying principles and forces of flight. Sometimes called "Father of Aviation", in 1799 he set forth concept of the modern aeroplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. Often known as "the father of Aerodynamics", he was a pioneer of aeronautical engineering. Designer of the first successful glider to carry a human being aloft, he discovered and identified the four aerodynamic forces of flight - weight, lift, drag, and thrust which are in effect on any flight vehicle. Modern aeroplane design is based on those discoveries including cambered wings. He is credited with the first major breakthrough in heavier-than-air flight and he worked over half a century before the development of powered flight.
Captured by the optimism of the times, he engaged in a wide variety of engineering projects. Among the many things that he developed are self-righting lifeboats, tension-spoke wheels, the "Universal Railway" (his term for caterpillar tractors), automatic signals for railway crossings, seat belts, small scale helicopters, and a kind of prototypical internal combustion engine fueled by gun powder. He also contributed in the fields of prosthetics, air engines, electricity, theatre, architecture, ballistics, optics, and land reclamation.
He is mainly remembered, however, for his pioneering studies and experiments with flying machines, including the working, piloted glider that he designed and built. He wrote a landmark three-part treatise titled "On Aerial Navigation" (1809-1810), which was published in Nicholson's "Journal of Natural Philosophy, Chemistry and the Arts". The recent (2007) discovery of cartoons in Cayley's school notebooks (held in the archive of the Royal Aeronautical Society Library in London, England) reveal that even at school Cayley was developing his ideas on the theories of flight. It has been claimed that these images indicate that Cayley modeled the principles of a lift-generating inclined plane as early as 1792.
To measure the drag on objects at different speeds and angles of attack, he later built a 'whirling-arm apparatus" - a development of earlier work into ballistics and air resistance. He also experimented with rotating wing sections of various forms in the stairwells at Brompton Hall. These scientific experiments led him to develop an efficient cambered airfoil and to identify the four vector forces that influence an aircraft: thrust, lift, drag, and gravity. He discovered the importance of dihedral for lateral stability in flight, and deliberately set the center of gravity of many of his models well below the wings for this reason; these mechanics influenced the development of hang gliders. As a result of his investigations into many other theoretical aspects of flight, many now acknowledge him as the first aeronautical engineer.
By 1804 his model gliders appeared similar to modern aircraft: a pair of large monoplane wings towards the front, with a smaller tailplane at the back comprising horizontal stabilizers and a vertical fin. During some point prior to 1849 he designed and built a triplane powered with 'flappers' in which an unknown ten-year-old boy flew. Later, with the continued assistance of his grandson George John Cayley and his resident engineer Thomas Vick, he developed a larger scale glider (also probably fitted with 'flappers') which flew across Brompton Dale in 1853. A recent (2007) biography of Cayley (Richard Dee's "The man who discovered flight: George Cayley and the first airplane") claims the first pilot was Cayley's grandson George John Cayley (1826-1878). Dee's book also reports the re-discovery of a series doodles from Cayley's school exercise book which suggest that Cayley's first designs concerning a lift-generating inclined plane may have been made as early as 1793.
A replica of the 1853 machine was flown at the original site in Brompton Dale in 1974 and in the mid 1980s by Derek Piggott. The glider is currently on display at the Yorkshire Air Museum. Another replica flew there in 2003, first piloted by Allan McWhirter and later by Richard Branson."

1774 Biot (21 April 1774 – 3 February 1862)
"a French physicist, astronomer, and mathematician who established the reality of meteorites, made an early balloon flight, and studied the polarization of light.
Biot served in the artillery before he was appointed professor of mathematics at Beauvais in 1797. He later went on to become a professor of physics at the College de France around 1800, and three years later was elected as a member of the Academy of Sciences. In 1804 Biot was on board for the first scientific hot-air balloon ride with Gay-Lussac. Biot was also a member of the Legion of Honor; he was elected chevalier in 1814 and commander in 1849. In 1816, he was elected a foreign member of the Royal Swedish Academy of Sciences. In addition, Biot received the Rumford Medal, awarded by the Royal Society in the field of thermal or optic properties of matter, in 1840.
The Biot-Svart Law in magnetism is named after Biot and his colleague Felix Savart for their work in 1820. In their experiment they showed a connection between electricity and magnetism by “starting with a long vertical wire and a magnetic needle some horizontal distance apart [and showing] that running a current through the wire caused the needle to move” (Parsley). In 1803 Biot was sent by the French Academy to report back on 3000 meteorites that fell on L'Aigle, France. He found that the meteorites, or stones at the time, were from outer space. With his report, Biot helped support Ernst Florens Friedrich Chladni's argument that meteorites were debris from space, which he had published in 1794. Prior to Biot’s thorough investigation of the meteorites that fell near l’Aigle, France in 1803, very few truly believed that rocks found on Earth could have extraterrestrial origins. There were anecdotal tales of unusual rocks found on the ground after fireballs had been seen in the sky, but such stories were often dismissed as fantasy. Serious debate concerning the unusual rocks began in 1794 when German physicist Chladni published a book claiming that rocks had an extraterrestrial origin (Westrum). Only after Biot was able to analyze the rocks at l’Aigle was it commonly accepted that the fireballs seen in the sky were meteors falling through the atmosphere. Since Biot’s time, analysis of meteorites has resulted in accurate measurements of the chemical composition of the solar system. The composition and position of meteors in the solar system have also given astronomers clues as to how the solar system formed.
Biot also helped further the field of optics in 1815 with a study in polarized light. In his experiment Biot studied the effects of polarized light as it penetrated organic substances and determined that light “could be rotated clockwise or counterclockwise, dependent upon the optical axis of the material”. In 1812, Biot turned his attention to the study of optics, particularly the polarization of light. Prior to the 19th century, light was believed to consist of discrete packets called corpuscles. During the early 19th century, many scientists began to disregard the corpuscular theory in favor of the wave theory of light. Biot began his work on polarization to show that the results he was obtaining could only happen if light were made of corpuscles. His work in chromatic polarization and rotary polarization greatly advanced the field of optics, although it was later shown that his findings could also be obtained using the wave theory of light (Frankel). Biot’s work on the polarization of light has lead to significant breakthroughs in the field of optics."

1775 Ampere (20 January 1775 – 10 June 1836)
"A French physicist and mathematician who is generally regarded as one of the main discoverers of electromagnetism. The SI unit of measurement of electric current, the ampere, is named after him.
He spent his childhood and adolescence at the family property at Poleymieux-au-Mont-d'Or near Lyon. His father began to teach him Latin, until he discovered the boy's preference and aptitude for mathematical studies. The young Ampere, however, soon resumed his Latin lessons, to enable him to master the works of Euler and Bernoulli. In later life Ampere claimed that he knew as much about mathematics and science when he was eighteen as ever he knew; but, a polymath, his reading embraced history, travels, poetry, philosophy, and the natural sciences.
Ampere's fame mainly rests on his establishing the relations between electricity and magnetism, and in developing the science of electromagnetism, or, as he called it, electrodynamics. On 11 September 1820 he heard of H. C. Orsted's discovery that a magnetic needle is acted on by a voltaic current. Only a week later, on 18 September, Ampere presented a paper to the Academy containing a far more complete exposition of that and kindred phenomena. On the same day, Ampere also demonstrated before the Academy that parallel wires carrying currents attract or repel each other, depending on whether currents are in the same (attraction) or in opposite directions (repulsion). This laid the foundation of electrodynamics.
The field of electromagnetism thus opened up, Ampere explored with characteristic industry and care, and developed a mathematical theory which not only explained the electromagnetic phenomena already observed, but also predicted many new ones.
In 1828, he was elected a foreign member of the Royal Swedish Academy of Sciences."

1777 Gauss (30 April 1777 – 23 February 1855)
"A German mathematician and scientist who contributed significantly to many fields, including number theory, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy, and optics. Sometimes referred to as the "the Prince of Mathematicians" and "greatest mathematician since antiquity," Gauss had a remarkable influence in many fields of mathematics and science and is ranked as one of history's most influential mathematicians. He referred to mathematics as "the queen of sciences."
Gauss was a child prodigy. There are many anecdotes pertaining to his precocity while a toddler, and he made his first ground-breaking mathematical discoveries while still a teenager. He completed "Disquisitiones Arithmeticae" his magnum opus, in 1798 at the age of 21, though it was not published until 1801. This work was fundamental in consolidating number theory as a discipline and has shaped the field to the present day.
While in university, Gauss independently rediscovered several important theorems; his breakthrough occurred in 1796 when he was able to show that any regular polygon with a number of sides which is a Fermat prime (and, consequently, those polygons with any number of sides which is the product of distinct Fermat primes and a power of 2) can be constructed by compass and straight edge. This was a major discovery in an important field of mathematics; construction problems had occupied mathematicians since the days of the Ancient Greeks.
In his 1799 doctorate in absentia, Gauss proved the fundamental theorem of algebra which states that every non-constant single-variable polynomial over the complex numbers has at least one root. Mathematicians including jean le Rond d'Alembert had produced false proofs before him, and Gauss's dissertation contains a critique of d'Alembert's work...he subsequently produced three other proofs, the last one in 1849 being generally rigorous. His attempts clarified the concept of complex numbers considerably along the way.
Gauss also made important contributions to number theory with his 1801 book Disquisitiones Arthmeticae. which contained a clean presentation of modular arithmetic and the first proof of the law of quadratic reciprocity.
The discovery of Ceres by Piazzi on 1 January 1801 led Gauss to his work on a theory of the motion of planetoids disturbed by large planets, eventually published in 1809 under the name "Theory of motion of the celestial bodies moving in conic sections around the sun". After three months of intense work, he predicted a position for Ceres in December 1801—just about a year after its first sighting—and this turned out to be accurate within a half-degree. In the process, he so streamlined the cumbersome mathematics of 18th century orbital prediction that his work—published a few years later as "Theory of Celestial Movement" - remains a cornerstone of astronomical computation. It introduced the Gaussian gravitational constant, and contained an influential treatment of the method of least squares, a procedure used in all sciences to this day to minimize the impact of measurement error. Gauss was able to prove the method in 1809 under the assumption of normally distributed errors ( Gauss-Markov theorem, or Gaussian) The method had been described earlier by Adrien-Marie Legendre in 1805, but Gauss claimed that he had been using it since 1795.
Gauss was a prodigious mental calculator. Reputedly, when asked how he had been able to predict the trajectory of Ceres with such accuracy he replied, "I used logarithms." The questioner then wanted to know how he had been able to look up so many numbers from the tables so quickly. "Look them up?" Gauss responded. "Who needs to look them up? I just calculate them in my head!" In 1818 Gauss, putting his calculation skills to practical use, carried out a geodesic survey of the state of Hanover, linking up with previous Danish surveys. To aid in the survey, Gauss invented the heliotrope, an instrument that uses a mirror to reflect sunlight over great distances, to measure positions.
Gauss also claimed to have discovered the possibility of non-Euclidean geometries but never published it. This discovery was a major paradigm shift in mathematics, as it freed mathematicians from the mistaken belief that Euclid's axioms were the only way to make geometry consistent and non-contradictory. Research on these geometries led to, among other things, Einstein's theory of general relativity, which describes the universe as non-Euclidean.
The survey of Hanover fueled Gauss's interest in differential geometry, a field of mathematics dealing with curves and surfaces. Among other things he came up with the notion of Gaussian curvature. This led in 1828 to an important theorem, the Theorema Egregium ("remarkable theorem" in Latin), establishing an important property of the notion of curvature. Informally, the theorem says that the curvature of a surface can be determined entirely by measuring angles and distances on the surface. That is, curvature does not depend on how the surface might be embedded in 3-dimensional space or 2-dimensional space.
In 1821, he was made a foreign member of the Royal Swedish Academy of Sciences.
In 1831 Gauss developed a fruitful collaboration with the physics professor Wilhelm Weber, leading to new knowledge in magnetism (including finding a representation for the unit of magnetism in terms of mass, length and time) and the discovery of Kirchhoff's circuit laws in electricity. They constructed the first electromechanical telegraph in 1833, which connected the observatory with the institute for physics in Göttingen. Gauss ordered a magnetic observatory to be built in the garden of the observatory, and with Weber founded the Magnetic Club, which supported measurements of earth's magnetic field in many regions of the world. He developed a method of measuring the horizontal intensity of the magnetic field which has been in use well into the second half of the 20th century and worked out the mathematical theory for separating the inner (core and crust) and outer (magnetospheric) sources of Earth's magnetic field."

1777 Oersted (14 August 1777 - 9 March 1851)
"a Danish physicist and chemist who is most widely known for observing that electric currents induce magnetic fields, an important aspect of electromagnetism. He shaped post-Kantian philosophy and advances in science throughout the late 19th century.
In 1824, Orsted founded a society to disseminate knowledge of the natural sciences. He was also the founder of predecessor organizations which eventually became the Danish Meteorological Institute and the Dutch patent and Trademark Office. Ostred was the first modern thinker to explicitly describe and name the thought experiment.
A leader of the so-called Danish Golden Age, Orsted was a close friend of Hans Christian Andersen and the brother of politician and jurist Anders Sandoe Orsted, who eventually served as Danish prime minister (1853–54).
The Oersted (Oe), the cgs unit of magnetic H-field strength, is named after him."

1778 Gay-Lussac (6 December 1778 – 9 May 1850)
"a French chemist and physicist. He is known mostly for two laws related to gases (and for his work on alcohol-water mixtures, which led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries).
In 1802 Gay-Lussac first formulated the law stating that if the mass and pressure of a gas are held constant then gas volume increases linearly as the temperature rises. This is sometimes written as V = k T, where k is a constant dependent on the type, mass, and pressure of the gas and T is temperature on an absolute scale. (In terms of the ideal gas law, k = n R / P).
In 1804 he and Jean-Bapiste Biot made a hot-air balloon ascent to a height of 6.4 kilometres in an early investigation of the Earth's atmosphere. He wanted to collect samples of the air at different heights to record differences in temperature and moisture
In 1805, together with his friend and scientific collaborator Alexander von Humboldt, he discovered that the composition of the atmosphere does not change with decreasing pressure (increasing altitude). They also discovered that water is formed by two parts of hydrogen and one part of oxygen (by volume).
In 1808, he was the co-discoverer of boron.
In 1810, in collaboration with Louis Thenard, he developed a method for quantitative elemental analysis by measuring the CO2 and O2 evolved by reaction with potassium chlorate.
In 1811, Gay-Lussac recognized iodine as a new element, described its properties, and suggested the name iode.
In 1824, he developed an improved version of the burette that included a side arm, and coined the terms "pipette" and "burette" in an 1824 paper about the standardization of indigo solutions. "

1781 Poisson (21 June 1781 – 25 April 1840)
"A French mathematician, geometer, and physicist.
In 1798, he entered the Ecole Polytechnique in Paris as first in his year, and immediately began to attract the notice of the professors of the school, who left him free to make his own choices as to what he would study. In 1800, less than two years after his entry, he published two memoirs, one on Etienne Bezout's method of elimination, the other on the number of integrals of a finite difference equation. The latter was examined by Sylvestre-Francois lacroix and Adrien-Marie Legendre, who recommended that it should be published in the "Recueil des savants etrangers", an unprecedented honour for a youth of eighteen. This success at once procured entry for Poisson into scientific circles. Joseph Louis Lagrange, whose lectures on the theory of functions he attended at the Ecole Polytechnique, recognized his talent early on, and became his friend, while Pierre-Simon Laplace, in whose footsteps Poisson followed, regarded him almost as his son. The rest of his career, till his death in Sceaux near Paris, was almost entirely occupied by the composition and publication of his many works and in fulfilling the duties of the numerous educational positions to which he was successively appointed.
Immediately after finishing his studies at the École Polytechnique, he was appointed teaching assistant there, a position which he had occupied as an amateur while still a pupil in the school; for his schoolmates had made a custom of visiting him in his room after an unusually difficult lecture to hear him repeat and explain it. He was made deputy professor in 1802, and, in 1806 full professor succeeding Jean Baptiste Joseph Fourier, whom Napoleon had sent to Grenoble. In 1808 he became astronomer to the Bureau des Longitudes, and when the Faculte des Sciences was instituted in 1809 he was appointed professor of rational mechanics. He went on to become a member of the Institute in 1812, examiner at the military school at Saint-Cyr, in 1815, graduation examiner at the Ecole Polytechnique in 1816, councillor of the university in 1820, and geometer to the Bureau des Longitudes succeeding Pierre-Simon Laplace in 1827.
In 1823, he was elected a foreign member of the Royal Swedish Academy of Sciences.
As a teacher of mathematics Poisson is said to have been extraordinarily successful, as might have been expected from his early promise at the Ecole Polytechnique. As a scientific worker, his productivity has rarely if ever been equalled. Notwithstanding his many official duties, he found time to publish more than three hundred works, several of them extensive treatises, and many of them memoirs dealing with the most abstruse branches of pure mathematics, applied mathematics, mathematical physics, and rational mechanics.
It was in the application of mathematics to physics that his greatest services to science were performed. Perhaps the most original, and certainly the most permanent in their influence, were his memoirs on the theory of electricity and magnetism, which virtually created a new branch of mathematical physics.
Next (or in the opinion of some, first) in importance stand the memoirs on celestial mechancis, in which he proved himself a worthy successor to Pierre-Simon Laplace. In the first of his memoirs, Poisson discusses the famous question of the stability of the planetary orbits, which had already been settled by Lagrange to the first degree of approximation for the disturbing forces. Poisson showed that the result could be extended to a second approximation, and thus made an important advance in planteary theory. The memoir is remarkable inasmuch as it roused Lagrange, after an interval of inactivity, to compose in his old age one of the greatest of his memoirs. So highly did Legrange think of Poisson's memoir that he made a copy of it with his own hand, which was found among his papers after his death.
Poisson's well-known correction of Laplace's second order partial differential equation for potential.
In 1812 Poisson discovered that Laplace's equation is valid only outside of a solid. A rigorous proof for masses with variable density was first given by Carl Friedrich Gauss in 1839. Both equations have their equivalents in vector algebra.
In pure mathematics, his most important works were his series of memoirs on definite integrals and his discussion of Fourier series, the latter paving the way for the classic researches of peter Gustav Lejeune Dirichlet and Bernhard Riemann on the same subject. He also studied Fourier integrals. We may also mention his essay on the calculus of variations, and his memoirs on the probability of the mean results of observations. The Poisson distribution in probablility theory is named after him.
In his Traite de mechanique (2 vols. 8vo, 1811 arid 1833), which was written in the style of Laplace and Lagrange and was long a standard work, he showed many novelties such as an explicit usage of momenta, which influenced the work of Hamilton and Jacobi.
In 1815 Poisson studied integrations along paths in the complex plane. In 1831 he derived the Navier-Stokes equations independently of Claude-Louis Navier. "

1785 Navier (10 February 1785 – 21 August 1836)
"A French engineer and physicist who specialized in mechanics. The Navier-Stokes equations are named after him and George Gabriel Stokes.
In 1802, Navier enrolled at the Ecole polytechnique, and in 1804 continued his studies at the Ecole nationale des Ponts et Chaussees, from which he graduated in 1806. He eventually succeeded his uncle as Inspector General at the Corps des Ponts et Chaussees. He directed the construction of bridges at Choisy, Asnieres and Argenteuil in the Department of the Seine, and built a footbridge to the Ile de la Cite' in Paris.
In 1824, Navier was admitted into the french Academy of Science. In 1830, he took up a professorship at the Ecole Nationale des Ponts et Chaussees, and in the following year succeeded exiled Augustin Louis Cauchy as professor of calculus and mechanics at the Ecole polytechnique.
Navier formulated the general theory of elasticity in a mathematically usable form (1821), making it available to the field of construction with sufficient accuracy for the first time. In 1819 he succeeded in determining the zero line of mechanical stress, finally correcting Galileo Galilei's incorrect results, and in 1826 he established the elastic modulus as a property of materials independent of the second moment of area. Navier is therefore often considered to be the founder of modern structural analysis.
His major contribution however remains the Navier-Stokes equations (1822), central to fluid mechanics."

1788 Fresnel (10 May 1788 – 14 July 1827)
"A French physicist who contributed significantly to the establishment of the theory of wave optics. Fresnel studied the behavior of light both theoretically and experimentally.
He is perhaps best known as the inventor of the Fresnel lens, first adopted in lighthouses while he was a French commissioner of lighthouses, and found in many applications today.
Fresnel was the son of an architect. His early progress in learning was slow, and he still could not read when he was eight years old. At sixteen and a half the Ecole Polytechnique, where he acquitted himself with distinction. From there he went to the Ecole des Ponts et Chaussees.
He appears to have begun his research in optics around 1814 when he prepared a paper on the aberration of light, although it was never published. In 1818 he wrote a memoir on diffraction for which he received the prize of the Academie des Sciences at Paris in the ensuing year. He was the first to construct a special type of lens, now called a Fresnel lens, as a substitute for mirrors in lighthouses. In 1819 he was nominated to be a commissioner of lighthouses. In 1823 he was unanimously elected a member of the academy, and in 1825 he became a member of the Royal Society of London.
He received only scant public recognition during his lifetime for his labours in the cause of optical science. Some of his papers were not printed by the Academie des Sciences until many years after his death. But as he wrote to Young in 1824: in himself "that sensibility, or that vanity, which people call love of glory" had been blunted. "All the compliments," he says, "that I have received from Arago, Laplace, and Biot never gave me so much pleasure as the discovery of a theoretic truth, or the confirmation of a calculation by experiment."
His discoveries and mathematical deductions, building on experimental work by Thomas Young, extended the wave theory of light to a large class of optical phenomena. In 1817, Young had proposed a small transverse component to light, while yet retaining a far larger longitudinal component. Fresnel, by the year 1821, was able to show via mathematical methods that polarization could be explained only if light was entirely transverse, with no longitudinal vibration whatsoever.
His use of two plane mirrors of metal, forming with each other an angle of nearly 180°, allowed him to conclusively account for the phenomenon of interference in accordance with the wave theory.
With Francois Arago he studied the laws of the interference of polarized rays."

1789 Ohm (16 March 1789 – 6 July 1854)
"a German physicist. As a high school teacher, Ohm began his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current - now known as Ohm's law.
Using the results of his experiments, Ohm was able to define the fundamental relationship among voltage, current, and resistance, which represents the true beginning of electrical circuit analysis.
Although Ohm's work strongly influenced theory, at first it was received with little enthusiasm. However, his work was eventually recognized by the Royal Society with its award of the Copley Medal in 1841. He became a foreign member of the Royal Society in 1842, and in 1845 he became a full member of the Bavarian Academy of Sciences and Humanities. "

1789 Cauchy (21 August 1789 – 23 May 1857)
"A French mathematician who was an early pioneer of analysis. He started the project of formulating and proving the theorems of infinitesimal calculus in a rigorous manner. He also gave several important theorems in complex analysis and initiated the study of permutation groups in abstract algebra. A profound mathematician, Cauchy exercised a great influence over his contemporaries and successors. His writings cover the entire range of mathematics and mathematical physics.
Cauchy was a prolific writer; he wrote approximately eight hundred research articles and five complete textbooks. He was a devout Roman Catholic, strict (Bourbon) royalst, and a close associate of the Jesuit order.
The Cauchy family survived the revolution and the following Reign of Terror (1794) by escaping to Arcueil, where Cauchy received his first education, from his father. After the death of Robespierre (1794), it was safe for the family to return to Paris. There Louis-François Cauchy found himself a new bureaucratic job, and quickly moved up the ranks. When Napoleon Bonaparte came to power (1799), Louis-François Cauchy was further promoted, and became Secretary-General of the Senate, working directly under Laplace (who is now better known for his work on mathematical physics). The famous mathematician Lagrange was also no stranger in the Cauchy family.
On Lagrange's advice, Augustin-Louis was enrolled in the Ecole Centrale du Pantheon, the best secondary school of Paris at that time, in the fall of 1802. Most of the curriculum consisted of classical languages; the young and ambitious Cauchy, being a brilliant student, won many prizes in Latin and Humanities. In spite of these successes, Augustin-Louis chose an engineering career, and prepared himself for the entrance examination to the Ecole Polytechnique.
In 1805 he placed second out of 293 applicants on this exam, and he was admitted. One of the main purposes of this school was to give future civil and military engineers a high-level scientific and mathematical education. The school functioned under military discipline, which caused the young and pious Cauchy some problems in adapting. Nevertheless, he finished the Polytechnique in 1807, at the age of 18, and went on to the Ecole des Ponts et Chasussees (School for Bridges and Highways). He graduated in civil engineering, with the highest honors.
After finishing school in 1810, Cauchy accepted a job as a junior engineer in Cherbourg, where Napoleon intended to build a naval base. Here Augustin-Louis stayed for three years, and although he had an extremely busy managerial job, he still found time to prepare three mathematical manuscripts, Cauchy's first two manuscripts (on polyhedra) were accepted; the third one (on directrices of conic sections) was rejected.
In September 1812, now 23 years old, after becoming ill from overwork, Cauchy returned to Paris. Another reason for his return to the capital was that he was losing his interest in his engineering job, being more and more attracted to abstract beauty of mathematics; in Paris he would have a much better chance to find a mathematics related position. Although he formally kept his engineering position, he was transferred from the payroll of the Ministry of the Marine to the Ministry of the Interior. The next three years Augustin-Louis was mainly on unpaid sick leave, and spent his time quite fruitfully, working on mathematics (on the related topics of symmetric functions, the symmetric group and the theory of higher order algebraic equations). He attempted admission to the First Class of the Institut de France, but failed on three different occasions between 1813 and 1815. In 1815 Napoleon was defeated at Waterloo, and the newly installed Bourbon king louis XVIII appointed Cauchy to take the place of those removed for politically disfavor. The reaction by Cauchy's peers was harsh; they considered his acceptance of membership of the Academy an outrage, and Cauchy thereby created many enemies in scientific circles.
The genius of Cauchy was illustrated in his simple solution of the problem of Apollonius - describing a circle touching three given circles—which he discovered in 1805, his generalization of Euler's formula on polyhedra in 1811, and in several other elegant problems. More important is his memoir on wave propagation, which obtained the Grand Prix of the French Academy of Sciences in 1816. Cauchy's writings covered notable topics including: the theory of series, where he developed the notion of convergence and discovered many of the basic formulas for q-series. The theory of numbers and complex quantities; he was the first to define complex numbers as pairs of real numbers. The theory of groups and substitutions; and the theory of functions, differential equations, and determinants.
In the theory of light he worked on Fresnel's wave theory and on the dispersion and polarization of light. He also contributed significant research in mechanics, substituting the notion of the continuity of geometrical displacements for the principle of the continuity of matter. He wrote on the equilibrium of rods and elastic membranes and on waves in elastic media. He introduced a 3 × 3 symmetric matrix of numbers that is now known as the Cauchy stress tensor. In elasticity, he originated the theory of stress, and his results are nearly as valuable as those of Simeon Poisson. Other significant contributions include being the first to prove the Fermat polygonal number theorem.
However, Cauchy is most famous for his single-handed development of complex function theory.
In addition to his work on complex functions, Cauchy was the first to stress the importance of rigor in analysis; he clarified the principles of the calculus by developing them with the aid of infinitesimals, limits, and continuity, and was the first to prove Taylor's theorem rigorously, establishing his well-known form of the remainder. He wrote a textbook for his students at the Ecole Polytechnique in which he developed the basic theorems of mathematical analysis as rigorously as possible. In this book he gave the necessary and sufficient condition for the existence of a limit in the form that is still taught.
In modern control theory textbooks, the Cauchy argument principle is quite frequently used to derive the Nyquist stability criterion, which can be used to predict the stability of negative feedback amplifier and negative feedback control systems. Thus Cauchy's work has a strong impact on both pure mathematics and practical engineering.
Cauchy was very productive, in number of papers second only to Leonhard Euler. It took almost a century to collect all his writings into 27 large volumes."

1791 Savart (June 30, 1791 – March 16, 1841)
"A professor at the College de France in 1836 and was the co-originator of the Biot-Savart Law, along with Jean-Baptiste Biot. Together, they worked on the theory of magnetism and electrical currents. Their law was developed about 1820. The Biot-Savart Law relates magnetic fields to the currents which are their sources. Félix Savart also studied acoustics. He developed the Savart wheel which produces sound at specific graduated frequencies using rotating disks. Félix Savart is the namesake of the unit of measurement for musical intervals, the savart (though it was actually invented by Joseph Sauveur)."

1791 Faraday (22 September 1791 – 25 August 1867)
"an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry.
Faraday studied the magnetic field a conductor carrying a DC electric current, and established the basis for the electromagnetic field concept in physics. He discovered electromagnetic induction, diamagnetism, and laws of electrolysis. He established that magnetism could affect rays of light and that there was an underlying relationship between the two phenomena. His inventions of electromagnetic rotary devices formed the foundation of electric motor technology, and it was largely due to his efforts that electricty became viable for use in technology.
As a chemist, Michael Faraday discovered benzene, investigated the clathrate hydrate of chlorine, invented an early form of the Bunsen burner and the system of oxidation numbers, and popularized terminology such as anode, cathode, electrode, and ion.
Although Faraday received little formal education and knew little of higher mathematics, such as calculus, he was one of the most influential scientists in history. Some historians of science refer to him as the best experimentalist in the history of science. The SI unit of capacitance, the farad, is named after him, as is the Faraday constant, the charge on a mole of electrons (about 96,485 coulombs). Faraday's law of induction states that a magnetic field changing in time creates a proportional electromotive force.
Albert Einstein kept a photograph of Faraday on his study wall alongside pictures of Issac Newton and James Clert Maxwell.
Faraday was highly religious; he was a member of the Sandemanian Church, a Christian sect founded in 1730 which demanded total faith and commitment. Biographers have noted that "a strong sense of the unity of God and nature pervaded Faraday's life and work."
The young Michael Faraday, the third of four children, having only the most basic of school educations, had to largely educate himself. At fourteen he became apprenticed to a local bookbinder and bookseller and during his seven-year apprenticeship, he read many books, including Issac Watt's "The Improvement of the Mind", and he enthusiastically implemented the principles and suggestions that it contained. He developed an interest in science, especially in electricity. In particular, he was inspired by the book "Conversations in Chemistry" by Jane Marcet.
Faraday's earliest chemical work was as an assistant to Humphry Davy, Faraday made a special study of chlorine, and discovered two new chlorides of carbon. He also made the first rough experiments on the diffusion of gases, a phenomenon first pointed out by John Dalton.
He succeeded in liquefying several gases; he investigated the alloys of steel, and produced several new kinds of glass intended for optical purposes. A specimen of one of these heavy glasses afterwards became historically important as the substance in which Faraday detected the rotation of the plane of polarization of light when the glass was placed in a magnetic field, and also as the substance which was first repelled by the poles of the magnet.
Faraday built two devices to produce what he called electromagnetic rotation: a continuous circular motion from the circular magnetic force around a wire and a wire extending into a pool of mercury with a magnet placed inside would rotate around the magnet if supplied with current from a chemical battery. The latter device is known as a homopolar motor. These experiments and inventions form the foundation of modern electromagnetic technology
From his initial electromagnetic (EM) discovery in 1821, Faraday continued his laboratory work exploring properties of materials and developing the requisite experience. In 1824, Faraday briefly set up a circuit to study whether a magnetic field could regulate the flow of a current in an adjacent wire, but could find no such relationship. This lab followed similar work with light and magnets three years earlier with identical results. During the next seven years, Faraday spent much of his time perfecting his recipe for optical quality (heavy) glass, boro-silicate of lead , which he used in his future studies connecting light with magnetism. In his spare time from this optics work, Faraday continued publishing his experimental work (some of which related to EM) and conducted foreign correspondence with scientists (also working on EM) he previously met on his journeys about Europe with Davy. Two years after the death of Davy, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. Joseph Henry likely discovered self-induction a few months earlier (and both may have been anticipated by the work of Francesco Zantedeschi in Italy in 1829 and 1830).
Faraday's breakthrough came when he wrapped two insulated coils of wire around an iron ring, and found that upon passing a current through one coil, a momentary current was induced in the other coil. This phenomenon is known as mutual induction. The iron ring-coil apparatus is still on display at the Royal Institution. In subsequent experiments he found that if he moved a magnet through a loop of wire, an electric current flowed in the wire. The current also flowed if the loop was moved over a stationary magnet. His demonstrations established that a changing magnetic field produces an electric field. This relation was modelled mathematically by james Clerk Maxwell as Faraday's law, which subsequently became one of the four Maxwell equations. These in turn have evolved into the generalization known today as field theory. Faraday later used the principle to construct the electric dynamo, the ancestor of modern power generators.
In 1839 he completed a series of experiments aimed at investigating the fundamental nature of electricity. Faraday used "static", batteries, and "animal electricity" to produce the phenomena of electrostatic attraction, electrolysis, magnetism, etc. He concluded that, contrary to scientific opinion of the time, the divisions between the various "kinds" of electricity were illusory. Faraday instead proposed that only a single "electricity" exists, and the changing values of quantity and intensity (current and voltage) would produce different groups of phenomena.
Near the end of his career Faraday proposed that electromagnetic forces extended into the empty space around the conductor. This idea was rejected by his fellow scientists, and Faraday did not live to see this idea eventually accepted. Faraday's concept of lines of flux emanating from charged bodies and magnets provided a way to visualize electric and magnetic fields. That mental model was crucial to the successful development of electromechanical devices which dominated engineering and industry for the remainder of the 19th century.
In 1845, Faraday discovered that many materials exhibit a weak repulsion from a magnetic field, a phenomenon he named diamagnetism. Faraday also found that the plane of polarization of linearly polarized light can be rotated by the application of an external magnetic field aligned in the direction the light is moving. This is now termed the Faraday effect. He wrote in his notebook, "I have at last succeeded in "illuminating a magnetic curve" or "line of force" and in "magnetizing a ray of light". This established that magnetic force and light were related.
In his work on static electricity, Faraday demonstrated that the charge only resided on the exterior of a charged conductor, and exterior charge had no influence on anything enclosed within a conductor. This is because the exterior charges redistribute such that the interior fields due to them cancel. This shielding effect is used in what is now known as a Faraday cage.
Faraday undertook numerous, and often time-consuming, service projects for private enterprise and the British government. This work included investigations of explosions in coal mines...a meticulous forensic investigation and indicated that coal dust contributed to the severity of the explosion that killed 95 miners.
Faraday spent extensive amounts of time on projects such as the construction and operation of light houses and protecting the bottoms of ships from corrosion.
Faraday also was active in what would now be called environmental science or engineering. He investigated industrial pollution at Swansea and was consulted on air pollution at the Royal Mint. In July 1855, Faraday wrote a letter to The Times on the subject of the foul condition of the River Thames.
During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society. Faraday was elected a foreign member of the Royal Swedish Academy of Sciences in 1838, and was one of eight foreign members elected to the French Academy of Sciences in 1844.
When asked by the British government to advise on the production of chemical weapons for use in the Crimean War (1853–1856), Faraday refused to participate citing ethical reasons."

1792 Coriolis (21 May 1792 – 19 September 1843)
"A French mathematician, mechanical engineer and scientist. He is best known for his work on the supplementary forces that are detected in a rotating frame of reference, and one of those forces nowadays bears his name. Coriolis was the first to coin the term "work" for the transfer of energy by a force acting through a distance.
Coriolis was born in Paris. In 1816 he became a tutor at the Ecole Polytechnique. Here he did experiments on friction and hydraulics.
In 1829 Coriolis published a textbook, "Calculation of the Effect of Machines", which presented mechanics in a way that could readily be applied by industry. In this period the correct expression for kinetic energy, 1/2 mv^2, and its relation to mechanical work became established.
During the following years Coriolis worked to extend the notion of kinetic energy and work to rotating systems. The first of his papers, "On the principle of kinetic energy in the relative motion in machines", was read to the Academie des Sciences (Coriolis 1832). Three years later came the paper that would make his name famous, "On the equations of relative motion of a system of bodies". Coriolis's papers do not deal with the atmosphere or even the rotation of the earth, but with the transfer of energy in rotating systems like waterwheels. Coriolis discussed the supplementary forces that are detected in a rotating frame of reference and he divided these forces into two categories. The second category contained the force that would eventually bear his name.
In 1835 he published a mathematical work on collisions of spheres: "Theorie Mathématique des Effets du Jeu de Billard", considered a classic on the subject.
Coriolis's name began to appear in the meteorological literature at the end of the 19th century, although the term "Coriolis force" was not used until the beginning of the 20th century. Today, the name Coriolis has become strongly associated with meteorology, but all major discoveries about the general circulation and the relation between the pressure and wind fields were made without knowledge about Gaspard Gustave Coriolis.
Coriolis became professor of mechanics at the Ecole Centrale des Arts of Manufactures in 1829. Upon the death of Navier in 1836, Coriolis succeeded him in in the chair of applied mechanics at the Ecole des Ponts and Chaussees and to Navier's place in the Academie of Sciences. In 1838 he succeeded Dulong as director of studies in the Ecole Polytechnique."

1799 Clapeyron (26 February 1799 – 28 January 1864)
"A French engineer and physicist, one of the founders of thermodynamics. Clapeyron studied at the Ecole Polytechnique and Ecole des Mines, before leaving for Saint Petersburg in 1820 to teach at the Ecole des Travaux Publics. He returned to Paris only after the Revolution of July 1830, supervising the construction of the first railway line connecting Paris to Versailles and Saint-Germain.
In 1834, he made his first contribution to the creation of modern thermodynamics by publishing a report entitled the "Driving force of the heat", in which it developed the work of the physicist Nicholas leonard Sadi Carnot, deceased two years before. Though Carnot had developed a compelling analysis of a generalized heat engine, he had employed the clumsy and already unfashionable caloric theory.
Clapeyron, in his memoire, presented Carnot's work in a more accessible and analytic graphical form, showing the Carnot cycle as a closed curve on an indicator diagram, a chart of pressure against volume (named in his honor Clapeyron's graph).
In 1843, Clapeyron further developed the idea of a reversible process, already suggested by Carnot and made a definitive statement of Carnot's principle, what is now known as the second law of thermodynamics.
These foundations enabled him to make substantive extensions of Clausius' work, including the formula, now known as the Clausius-Clapeyron relation, which characterizes the phase transition between two phases of matter. He further considered questions of phase transitions in what later became known as Stefan problems (in relation to ice formation)."