Dec 132018

On this date in 1640 Robert Plot FRS was baptized. His date of birth is not recorder. He was an English naturalist, first Professor of Chemistry at the University of Oxford, and the first keeper of the Ashmolean Museum. He also hold the unique distinction of being the only seventeenth century English scientist who was wrong about absolutely every theory he proposed. I happen to know about him because he wrote about a strange English traditional custom, and his description is the oldest description of traditional dance we have.

Plot was born in Borden in Kent and educated at the Wye Free School. He entered Magdalen Hall, Oxford in 1658 where he received his BA in 1661 and an MA in 1664. He subsequently taught and served as dean and vice principal at Magdalen Hall while preparing for his BCL and DCL, which he received in 1671 before moving to University College in 1676. By this time, Plot had already developed an interest in the systematic study of natural history and antiquities. In June 1674, with patronage from John Fell, the bishop of Oxford, and Ralph Bathhurst, vice-chancellor of the university, Plot began studying and collecting artefacts throughout the nearby countryside, publishing his findings three years later in The Natural History of Oxford-shire. In this work, he described and illustrated various rocks, minerals and fossils, including the first known illustration of a dinosaur bone which he attributed to a giant (later recognized as the femur of a Megalosaurus), but believed that most fossils were not remains of living organisms but rather crystallizations of mineral salts with a coincidental zoological form.

The favorable reception of his findings not only earned him the nickname of the “learned Dr. Plot,” but also led to his election into the Royal Society of London on 6th December 1677, where he served as the society’s secretary and joint editor of the Philosophical Transactions (144–178) from 1682 through 1684. Another consequence of his success was his appointment as the first keeper of the newly established Ashmolean Museum in Oxford in 1683, as well as his simultaneous appointment as the first professor of chemistry in the new well-equipped laboratory housed within the museum.

In the field of chemistry he searched for a universal solvent that could be obtained from wine spirits, and believed that alchemy was necessary for medicine. In 1684, Plot published De origine fontium, a treatise on the source of springs, which he attributed to underground channels originating from the sea. Plot shifted his focus towards archaeology in the 1686 publication of his second book, The Natural History of Staffordshire, but misinterpreted Roman remains as Saxon. He also describes a double sunset viewable from Leek, the Abbots Bromley Horn Dance, and, for the first time, the Polish swan, a pale morph of the Mute swan.

Here is his description of the horn dance:

  1. At Abbots, or now rather Pagets Bromley, they had al∣so within memory, a sort of sport, which they celebrated at Christmas (on New-year, and Twelft-day) call’d the Hobby-horse dance, from a person that carryed the image of a horse between his leggs, made of thin boards, and in his hand a bow and arrow, which passing through a hole in the bow, and stopping upon a sholder it had in it, he made a snapping noise as he drew it to and fro, keeping time with the Musick: with this Man danced 6 others, carrying on their shoulders as many Rain deers heads, 3 of them painted white, and 3 red, with the Armes of the cheif families (viz. of Paget, Bagot, and Wells) to whom the revenews of the Town cheifly belonged, depicted on the palms of them, with which they danced the Hays, and other Country dances. To this Hobby-horse dance there also belong’d a pot, which was kept by turnes, by 4 or 5 of the cheif of the Town, whom they call’d Reeves, who provided Cakes and Ale to put in this pot; all people who had any kindness for the good in∣tent of the Institution of the sport, giving pence a piece for themselves and families; and so forraigners too, that came to see it: with which Mony (the charge of the Cakes and Ale be∣ing defrayed) they not only repaired their Church but kept their poore too: which charges are not now perhaps so cheer∣fully boarn.

There is no telling how accurate this description is, but it is unusually detailed for the era. You can find more on the dance in this post:  It contains a full appraisal of historical sources.

In 1687, Plot was made a notary public by the Archbishop of Canterbury as well as appointed the registrar to the Norfolk Court of Chivalry. Plot resigned from his posts at Oxford in 1690, thereafter marrying Rebecca Burman of London and retiring to his property of Sutton Barne in his hometown of Borden, where he worked on The Natural History of Middlesex and Kent but never completed. The office of Mowbray Herald Extraordinary was created in January 1695 for Plot, who was made registrar of the College of Heralds just two days later. Although able to go on an archaeological tour of Anglia in September 1695, Plot was greatly suffering from urinary calculi, and succumbed to his illness on 30th April 1696. He was buried at Borden Church, where a plaque memorializes him.

Here is a 17th century recipe for an apple paste from A Daily Exercise for Ladies and Gentlewomen (1617) used to make fake plums. It reminds me a little of marzipan fruits, and also makes a sardonic comment on Plot who appeared unable to see things for what they really were. The recipe is vague as to the temperature you have to achieve with the apple and sugar mix. I’m thinking around 250°F/120°C.

To make Paste of Pippins, after the Genua fashion, some like leaves, some like Plums, with stalkes and stones.

 Take and pare faire yellow Pippins, cut them in small pieces, stew them betwixt two dishes with two or three spoonefuls of Rosewater, and when they be boiled very tender, straine them then boile the weight of the pulp in double refined Sugar vnto a Candie height, and if you please put in a graine of Muske, and a quarter of an ounce of fine white ginger searced, and so let it boile vntill you see it come from the bottome of the Posnet, then fashion it on a sheete of glasse in some prettie forme as you thinke best, and stoue it either in a Stoue, or in a warme Ouen. If you desire to haue any of it red, colour it with a spoonefull of Conserue of Damsons, before you fashion it vpon your glasse or plate, and that will make shew as though it were made of red Plums. If you put a stone betwixt two halfes, will shew like a Plum, you may keepe Cherrie stalkes drie for the same purpose.

Dec 172016


Today is the birthday (1778) of Sir Humphry Davy, 1st Baronet PRS MRIA FGS, a Cornish chemist and inventor whom I remember chiefly as the inventor of the Davy safety lamp for miners, but who had an illustrious career as a chemist.  He isolated a series of elements for the first time – potassium, sodium,  calcium, strontium, barium, magnesium and boron, as well as discovering the elemental nature of chlorine and iodine. He also studied the forces involved in these separations, inventing the new field of electrochemistry. Besides the Davy Lamp he invented a very early form of the incandescent light bulb.

Davy was born in Penzance in Cornwall but his family moved to Varfell, near Ludgvan, when he was 9, and in term-time Davy boarded with John Tonkin, his mother’s godfather. After Davy’s father died in 1794, Tonkin apprenticed him to John Bingham Borlase, a surgeon with a practice in Penzance. In the apothecary’s dispensary, Davy became a chemist, and he conducted his earliest chemical experiments in a garret in Tonkin’s house. Davy’s friends said: “This boy Humphry is incorrigible. He will blow us all into the air.” His elder sister complained of the ravages made on her dresses by corrosive substances.

His Quaker friend and mentor Robert Dunkin remarked: ‘I tell thee what, Humphry, thou art the most quibbling hand at a dispute I ever met with in my life.’ One winter day he took Davy to a river to show him that rubbing two plates of ice together developed sufficient energy by motion, to melt them, and that after the motion was suspended, the pieces were united by regelation. Later, as professor at the Royal Institution, Davy repeated many of the ingenious experiments he learned from Dunkin.

Through a mutual friend he met Dr Edwards who was a lecturer in chemistry at St. Bartholomew’s Hospital (Barts). He permitted Davy to use his laboratory and possibly directed his attention to the floodgates of the port of Hayle, which were rapidly decaying as a result of the contact between copper and iron under the influence of seawater. Galvanic corrosion was not understood at that time, but the phenomenon prepared Davy for subsequent experiments on ship’s copper sheathing.

Thomas Beddoes and John Hailstone were engaged in a geological controversy on the rival merits of the Plutonian and Neptunist hypotheses. They traveled together to examine the Cornish coast for evidence of their competing theories and made Davy’s acquaintance. Beddoes, who had established at Bristol a ‘Pneumatic Institution,’ needed an assistant to superintend the laboratory. After prolonged negotiations, mainly by Gilbert, Mrs Davy and Borlase consented to Davy’s departure, but Tonkin wished him to remain in his native town as a surgeon, and altered his will when he found that Davy insisted on going to Dr Beddoes.On 2 October 1798, Davy joined the Pneumatic Institution at Bristol. It had been established to investigate the medical powers of factitious airs and gases, and Davy was to superintend the various experiments. The arrangement agreed between Dr Beddoes and Davy was liberal and enabled Davy to give up all claims on his paternal property in favor of his mother. He did not intend to abandon the medical profession and was determined to study and graduate at Edinburgh but he soon began to fill parts of the institution with voltaic batteries. While living in Bristol, Davy met the Earl of Durham, who was a resident in the institution for his health and became close friends with Gregory Watt, James Watt, Samuel Taylor Coleridge and Robert Southey, all of whom became regular users of nitrous oxide, to which Davy became addicted.


James Watt built a portable gas chamber to facilitate Davy’s experiments with the inhalation of nitrous oxide. At one point the gas was combined with wine to judge its efficacy as a cure for hangover (his laboratory notebook indicated success). The gas was popular among Davy’s friends and acquaintances, and he noted that it might be useful for performing surgical operations. However, anesthetics were not regularly used in medicine or dentistry until decades after Davy’s death. Davy conducted numerous experiments on himself with nitrous oxide, carbon monoxide, and with respiration at considerable risk.

In 1799, Count Rumford had proposed the establishment in London of an ‘Institution for Diffusing Knowledge’ that is, the Royal Institution. In 1801 Davy left Bristol to take up a new post at the Royal Institution as assistant lecturer in chemistry, director of the chemical laboratory, and assistant editor of the journals of the institution.  On 25 April 1801, Davy gave his first lecture on the relatively new subject of ‘Galvanism’. The first lecture garnered rave reviews, and by the June lecture Davy wrote to John King that his last lecture had attendance of nearly 500 people. “There was Respiration, Nitrous Oxide, and unbounded Applause. Amen!”


Davy’s lectures also included spectacular and sometimes dangerous chemical demonstrations for his audience, a generous helping of references to divine creation, and genuine scientific information. Not only a popular lecturer, the young and handsome Davy acquired a huge female following around London, and nearly half of the attendees pictured in Gillray’s cartoon of the Royal Institution are female. When Davy’s lecture series on Galvanism ended, he progressed to a new series on Agricultural Chemistry, and his popularity continued to skyrocket. By June 1802, after just over a year at the Institution and at the age of 23, Davy was nominated to full lecturer.

In 1802 Davy had what was then the most powerful electrical battery in the world at the Royal Institution. With it, Davy created the first incandescent light by passing electric current through a thin strip of platinum, chosen because the metal had an extremely high melting point. It was neither sufficiently bright nor long lasting enough to be of practical use, but demonstrated the principle. By 1806 he was able to demonstrate a much more powerful form of electric lighting to the Royal Society in London. It was an early form of arc light which produced its illumination from an electric arc created between two charcoal rods.


Davy was a pioneer in the field of electrolysis using the voltaic pile to split common compounds and thus prepare many new elements. He went on to electrolyze molten salts and discovered several new metals, including sodium and potassium. Davy discovered potassium in 1807, deriving it from caustic potash (KOH). Before the 19th century, no distinction had been made between potassium and sodium. Potassium was the first metal that was isolated by electrolysis. Davy isolated sodium in the same year by passing an electric current through molten sodium hydroxide. Davy discovered calcium in 1808 by electrolyzing a mixture of lime and mercuric oxide. He worked with electrolysis throughout his life and was first to isolate magnesium, boron, and barium.

Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it “dephlogisticated marine acid” and mistakenly thought it contained oxygen. Davy showed that the acid of Scheele’s substance, called at the time oxymuriatic acid, contained no oxygen. This discovery overturned Lavoisier’s definition of acids as compounds of oxygen. In 1810, chlorine was given its current name by Humphry Davy, who insisted that chlorine was in fact an element.

Davy later damaged his eyesight in a laboratory accident with nitrogen trichloride. Pierre Louis Dulong first prepared this compound in 1812, and lost two fingers and an eye in two separate explosions with it. Davy’s own accident induced him to hire Michael Faraday as a co-worker.

In 1812, Davy was knighted, gave a farewell lecture to the Royal Institution, and married a wealthy widow, Jane Apreece. (While Davy was generally acknowledged as being faithful to his wife, their relationship was stormy, and in later years he travelled to continental Europe alone.) In October 1813, he and his wife, accompanied by Michael Faraday as his scientific assistant (and valet), travelled to France to collect a medal that Napoleon Bonaparte had awarded Davy for his electro-chemical work. While in Paris, Davy was asked by Gay-Lussac to investigate a mysterious substance isolated by Bernard Courtois. Davy showed it to be an element, which is now called iodine. The party left Paris in December 1813, traveling south to Italy. They stayed a while in Florence, where, in a series of experiments conducted with Faraday’s assistance, Davy succeeded in using the sun’s rays to ignite diamond, proving it is composed of pure carbon.

Davy’s party continued to Rome, and also visited Naples and Mount Vesuvius. By June 1814, they were in Milan, where they met Alessandro Volta, and then continued north to Geneva. They returned to Italy via Munich and Innsbruck, and when their plans to travel to Greece and Istanbul were abandoned after Napoleon’s escape from Elba, they returned to England.


After his return to England in 1815, Davy experimented with lamps for use in coal mines. There had been many mining explosions caused by firedamp or methane often ignited by open flames of the lamps then used by miners. In particular the Felling mine disaster in 1812 near Newcastle caused great loss of life, and action was needed to improve underground lighting and especially the lamps used by miners. Davy conceived of using an iron gauze to enclose a lamp’s flame, and so prevent the methane burning inside the lamp from passing out to the general atmosphere. Although the idea of the safety lamp had already been demonstrated by William Reid Clanny and by the then unknown (but later very famous) engineer George Stephenson, Davy’s use of wire gauze to prevent the spread of flame was used by many other inventors in their later designs. George Stephenson’s lamp was very popular in the north-east coalfields, and used the same principle of preventing the flame reaching the general atmosphere, but by different means. Unfortunately, although the new design of gauze lamp initially did seem to offer protection, it gave much less light, and quickly deteriorated in the wet conditions of most pits. Rusting of the gauze quickly made the lamp unsafe, and the number of deaths from firedamp explosions rose yet further.

There was some discussion as to whether Davy had discovered the principles behind his lamp without the help of the work of Smithson Tennant, but it was generally agreed that the work of both men had been independent. Davy refused to patent the lamp, and its invention led to his being awarded the Rumford medal in 1816.

In January 1819, Davy was awarded a baronetcy. Although Sir Francis Bacon and Sir Isaac Newton had already been knighted, this was, at the time, the first such honor ever conferred on a man of science in Britain. A year later he became President of the Royal Society. Davy’s laboratory assistant, Michael Faraday, went on to enhance Davy’s work and would become the more famous and influential scientist. Davy is supposed to have even claimed Faraday as his greatest discovery. Davy later accused Faraday of plagiarism, however, causing Faraday (the first Fullerian Professor of Chemistry) to cease all research in electromagnetism until his mentor’s death.


Davy spent the last months of his life writing Consolations in Travel, an immensely popular, somewhat freeform compendium of poetry, thoughts on science and philosophy. Published posthumously, the work became a staple of both scientific and family libraries for several decades afterward. Davy spent the winter in Rome, hunting in the Campagna on his 50th birthday. But on 20 February 1829 he had a stroke. After spending many months attempting to recuperate, Davy died in a hotel room in Geneva on 29 May 1829.

He had wished to be buried where he died, but had also wanted the burial delayed in case he was only comatose. He refused to allow a post-mortem for similar reasons. But the laws of Geneva did not allow any delay and he was given a public funeral on the following Monday, in the Plainpalais Cemetery, outside the city walls. Jane organized a memorial tablet for him, in Westminster Abbey shortly afterwards.


In the spirit of Davy’s experiments the Royal Institution’s website gives a recipe for microwave cupcakes (or mug cakes) and suggests ways to experiment, Here’s the basic recipe slightly edited.  The point is to make the original first, and then play around with the ingredients and see what happens. RI asks the following questions:

What do you think will happen if we don’t include the egg?

How could we find out?

What do you think will happen if we don’t include the oil?

What do you think will happen if we don’t include the baking


Microwave Mug Cake


4 tbsp plain flour
2 tbsp caster sugar
¼ tsp baking powder
1 small/medium egg
2 tbsp vegetable oil
2 tbsp water


Mix all the dry ingredients together in a mug

Break the egg into the mug and add the oil and water

Stir vigorously with a fork

Zap the resulting mixture in your microwave at full power for 2 minutes


Oct 232016



Today is Mole Day, an unofficial holiday celebrated among chemists, chemistry students and chemistry enthusiasts on October 23, between 6:02 AM and 6:02 PM. No, it does not celebrate pesky little furry mammals who make hills that some people make into mountains. The mole is the unit of measurement in the International System of Units (SI) for the amount of a substance. You might have a tough time for a few seconds if your eyes glaze over when the subject of mathematics comes up. I promise to be quick.

The mole is widely used in chemistry as a convenient way to express relative amounts of reactants and products of chemical reactions. For example, the chemical equation 2 H2 + O2 → 2 H2O implies that 2 mol of dihydrogen (H2) and 1 mol of dioxygen (O2) react to form 2 mol of water (H2O). The mole may also be used to express the number of atoms, ions, or other elementary entities in a given sample of any substance. The concentration of a solution is commonly expressed by its molarity, defined as the number of moles of the dissolved substance per liter of solution. This takes me back to my days of quantitative analysis in chemistry lab in grammar school. I used to be all right with the experiments, but I always managed to get tripped up on the mathematics at the end. I knew my chemistry backwards, forwards, and inside out – yet I still managed to make a simple error in calculation on the quantitative analysis in the final lab exam for ‘O’- level and fretted for a month until the results were published. Crisis over. Even with one simple error in multiplication on one tiny part of the whole exam I still got the highest mark. Phew !!

The mole is based on Avogadro’s constant, which is approximately 6.02 × 1023 (actually more like 6.02214085774×1023) and which is the number of particles (usually atoms or molecules) in one mole of substance. In the US writing style today’s date is 10/23, so at 6:02 (the time I woke this morning as it happens – late for me), we can say that we have approximated Avogadro’s constant (6:02 10/23) in the same way that 10/6 (October 6 in US, 10 June in Britain) is Mad Hatter’s Day, or 22/7  (22 July in Britain) is Pi Approximation Day. Semi-officially, Mole Day runs from 6:02 am to 6:02 pm.


You can convert moles to grams by using the common isotope for carbon which is carbon-12. I mole of carbon-12 weighs 1 gram (which is also one way to define a gram – that is, 6.02 × 1023 atoms of carbon-12 = 1 gram). Carbon-12 is also the standard for all other atomic masses. Its nucleus contains 6 protons and 6 neutrons, giving a mass number of 12. Furthermore, carbon is the basic element of organic life because of its unique ability among all the elements to form long and complex chains or molecules. No other element even comes close in this ability. Without carbon there would be no life.


According to current theory, the Big Bang did not produce significant amounts of carbon or other heavy elements (heavier than lithium). Mostly the Big Bang produced hydrogen and helium (constituent elements of stars, including our sun).  The heavier elements need extremely high temperatures to fuse the lighter nuclei of hydrogen and helium to make heavier nuclei, but the Big Bang had “cooled” below that temperature after only about 10 seconds. After the Big Bang, only very dense exploding stars were capable of generating such high temperatures and pouring out heavy elements. So all the carbon in your body was once part of an exploding star (as was all the oxygen, nitrogen, calcium, potassium iron, etc). Congratulations – You Are Stardust.


If I go with molecules based on carbon-12 as today’s theme I have unlimited possibilities for recipes. Everything we eat, with the exception of salt, is organic (based on carbon). That’s not especially promising or limiting. But if we focus on Avogadro we can narrow things down. Avogadro’s full name was Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto, Count of Quaregna and Cerreto (9 August 1776 – 9 July 1856). He was born in Turin in the Piedmont region of northern Italy – then part of the kingdom of Sardinia. Avogadro graduated in ecclesiastical law at the late age of 31 and began to practice thereafter. But he soon became attracted to physics and mathematics and in 1809 started teaching them at a liceo (high school) in Vercelli, where his family lived and had some property.

In 1811, he published an article with the title Essai d’une manière de déterminer les masses relatives des molécules élémentaires des corps, et les proportions selon lesquelles elles entrent dans ces combinaisons (“Essay on Determining the Relative Masses of the Elementary Molecules of Bodies and the Proportions by Which They Enter These Combinations”), which contains Avogadro’s central hypothesis on atomic mass. In 1820, he became a professor of physics at the University of Turin. Avogadro was active in the revolutionary movement of March 1821. As a result, he lost his chair in 1823 (or, as the university officially declared, it was “very glad to allow this interesting scientist to take a rest from heavy teaching duties, in order to be able to give better attention to his researches”). Eventually, King Charles Albert granted a Constitution (Statuto Albertino) in 1848. Well before this, Avogadro had been recalled to the university in Turin in 1833, where he taught for another twenty years.


Turin is most famous in Italy for its chocolate. Turin chocolate firms make all manner of chocolate products but are famous for Gianduiotto, named after Gianduja, a local Commedia dell’arte mask. The city is also known for bicerin, a traditional hot drink made of espresso, drinking chocolate and whole milk served layered in a small rounded glass. Every year Turin organizes CioccolaTÒ, a two-week chocolate festival run with the main Piedmontese chocolate producers, such as Caffarel, Streglio, Venchi and others.


I’m not a big fan of chocolate, and even if I were to give you a recipe you’d need to come to Italy for the right ingredients (and atmosphere). The Piedmont region does have some savory dishes I like, however. One is paniscia, which in Italy is called “risotto” but is, in reality, a creamy version of the Hispanic staple, rice and beans. Paniscia originates in Novara, to the west of Turin, but is quite commonly found throughout Piedmont (and impossible to find elsewhere in Italy). You’ll have to make do with what you can find for meat/pork products. The whole Po Valley is famous for its regional sausages and hams. Use one or two semi-cured Italian pork sausages. Local ones in Piedmont are salam d’la duja, a somewhat soft, half-cured sausage finished submerged in pig fat, like a confit, and fidighina, with pig’s liver. Lardo is cured pork fat, for which you can substitute lard, and cotenna is cured pig skin, which you can replace with roast pork skin. Local cooks often use carnaroli rice rather than the more usual arborio rice used in risotto because it cooks up creamier.




¾ cup dried borlotti beans
½ head savoy cabbage, shredded
2 ribs celery, chopped
1 leek, cleaned well and chopped
4 oz Italian semi-cured sausage, diced
4 oz lardo or pork fat, diced
4 oz cooked pork skin, diced
¾ cup carnaroli (or arborio) rice
1 cup Italian red wine
1 tbspn butter (plus extra)
2 oz Parmigiano-Reggiano cheese
salt and pepper


Cover the beans with cold water and soak them overnight.

Drain the beans and put them in a pot with the cabbage, celery, leek and salt to taste. Cover with water and bring to a simmer. Cook until the beans are tender but not completely cooked (around 2 hours). Keep the pot warm.

Place the meats in a wide, deep, heavy skillet and warm over medium-high heat. When the lardo starts to melt, add the rice. Stir with a wooden spoon to coat the rice with the fat. Continue to cook  for 2 to 3 minutes. Add the wine and allow it to reduce, stirring constantly.

Now you begin the risotto-making process which takes time and experience. Place on ladle of the bean broth in the skillet and stir. Controlling the heat is crucial. The broth should not bubble vigorously nor simmer listlessly. Somewhere in between. When the broth has nearly been absorbed add another ladleful. Keep stirring as the rice cooks and add more broth as it is absorbed. After about 15 minutes check the rice. It should be close to cooked. Start adding the beans and vegetables with the broth towards the last 5 minutes. The rice should be al dente and the whole mixture will have a creamy texture.

Remove the skillet from the heat, let it rest for 5 minutes, then add the butter and cheese. Stir thoroughly until the butter and cheese melt and are incorporated. Serve immediately



Aug 262013


Today is the birthday (1743) of Antoine-Laurent de Lavoisier, a French nobleman whose work in chemistry had a major influence on the nature of scientific inquiry.   Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783), helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and was also the first to establish that sulfur was an element (1777) rather than a compound. He discovered that, although matter may change its form or shape, its mass always remains the same. In the interest of “full disclosure” let me say that I admire his work greatly, but I also lament the fact that the revolution in science he helped usher in has also ushered in an era in which many people believe that if something cannot be measured it is not real.  We have him to thank for the disenchantment of the Western world.


Lavoisier was born to a wealthy family in Paris, the son of an attorney at the Parlement de Paris. He inherited a large fortune at the age of five with the death of his mother. Lavoisier began his schooling at the Collège des Quatre-Nations (known as the Collège Mazarin) in Paris in 1754 at the age of 11. In his last two years (1760-1761) at the college his scientific interests were aroused, and he studied chemistry, botany, astronomy, and mathematics. In philosophy he was taught by Abbé Nicolas Louis de Lacaille, a distinguished mathematician and observational astronomer who imbued the young Lavoisier with an interest in meteorological observation. He also studied law and received a licentiate, but never practiced law.

Lavoisier’s devotion and passion for chemistry were largely influenced by Étienne Condillac, a prominent French scholar of the 18th century. From 1763 to 1767, he studied geology under Jean-Étienne Guettard. In collaboration with Guettard, Lavoisier worked on a geological survey of Alsace-Lorraine in June 1767. In 1764 he read his first paper to l’Académie Royale des Sciences (Royal Academy of Sciences), France’s elite scientific society, on the chemical and physical properties of gypsum (hydrated calcium sulfate), and in 1766 he was awarded a gold medal by the King for an essay on the problems of urban street lighting. In 1768 Lavoisier received a provisional appointment to l’Académie Royale des Sciences. In 1769, he worked on the first geological map of France.

At age 26, around the time he was elected to l’Académie, Lavoisier bought a share in the Ferme Générale, a tax farming financial company which advanced the estimated tax revenue to the royal government in return for the right to collect the taxes. Lavoisier attempted to introduce reforms in the French monetary and taxation system to help the poor. While in government work, he helped develop the metric system to secure uniformity of weights and measures throughout France. Lavoisier consolidated his social and economic position when, in 1771 at age 28, he married Marie-Anne Pierrette Paulze, the 13-year-old daughter of a senior member of the Ferme Générale. She was to play an important part in Lavoisier’s scientific career—notably, she translated English documents for him, including Richard Kirwan’s Essay on Phlogiston and Joseph Priestley’s research. In addition, she assisted him in the laboratory and created many sketches and carved engravings of the laboratory instruments used by Lavoisier and his colleagues for their scientific works.

lavoisier2  Lavoisier_decomposition_air

Lavoisier demonstrated with careful measurements that transmutation of water to earth (conceived of at the time as elements) was not possible. He burnt phosphorus and sulfur in air, and proved that the products weighed more than the original. Nevertheless, the weight gained was lost from the air. Thus, in 1789, he established the Law of Conservation of Mass, which is also sometimes called “Lavoisier’s Law.”

Repeating the experiments of Priestley, he demonstrated that air is composed of two parts, one of which combines with metals to form calxes (oxides). In Considérations Générales sur la Nature des Acides (1778), he demonstrated that the “air” (gas) responsible for combustion was also the source of acidity. The next year, he named this portion “oxygen” (Greek for “acid-former”), and the other “azote” (Greek for “no life”). Lavoisier thus has a claim to the discovery of oxygen along with Joseph Priestley and Carl Wilhelm Scheele. He also discovered that the “inflammable air” discovered by Cavendish — which he termed “hydrogen” (Greek for water-former) — combined with oxygen to produce a dew, as Priestley had reported, which appeared to be water. In Reflexions sur le Phlogistique (1783), Lavoisier showed the prevailing phlogiston theory of combustion (that there was an element called phlogiston that was responsible for burning) was untenable.


Lavoisier worked with Claude Louis Berthollet and others to devise a system of chemical nomenclature which serves as the basis of the modern system of naming chemical compounds. In his  Méthode de nomenclature chimique (Methods of Chemical Nomenclature) (1787), Lavoisier invented the system of naming and classification still largely in use today, including names such as sulfuric acid, sulfates, and sulfites.


Lavoisier’s Traité Élémentaire de Chimie (Elementary Treatise on Chemistry, 1789) was the first modern chemistry textbook, and presented a unified view of new theories of chemistry, contained a clear statement of the Law of Conservation of Mass, and denied the existence of phlogiston. In addition, it contained a list of elements, or substances that could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur. His list, however, also included light, and caloric, which he believed to be material substances. In the work, Lavoisier underscored the observational basis of his chemistry, stating “I have tried…to arrive at the truth by linking up facts; to suppress as much as possible the use of reasoning, which is often an unreliable instrument which deceives us, in order to follow as much as possible the torch of observation and of experiment.” Nevertheless, he believed that the real existence of atoms was philosophically impossible.


With Pierre-Simon Laplace, Lavoisier used a calorimeter to estimate the heat given off per unit of carbon dioxide produced. They found the same ratio for a flame and animals, indicating that animals produced energy by a type of combustion. Lavoisier believed in the radical theory, believing that radicals, which function as a single group in a chemical reaction, would combine with oxygen in reactions. He believed all acids contained oxygen (later proven wrong). He also discovered that diamond is a crystalline form of carbon. Lavoisier made many fundamental contributions to the science of chemistry. Following Lavoisier’s work, chemistry acquired a strict quantitative nature, allowing reliable predictions to be made. The revolution in chemistry which he brought about was a result of a conscious effort to fit all experiments into the framework of a single theory.

As the French Revolution gained momentum from 1789 on, Lavoisier’s world inexorably collapsed around him. Attacks mounted on the deeply unpopular Ferme Générale, and it was eventually suppressed in 1791. In 1792 Lavoisier was forced to resign from his post on the Gunpowder Commission and to move from his house and laboratory at the Royal Arsenal. On August 8, 1793, all the learned societies, including the l’Académie Royale des Sciences, were suppressed.

He tried to remain aloof from the political arena, no doubt fearful and uncomprehending of the violence he saw. However, on Nov. 24, 1793, the arrest of all the former tax gatherers was ordered. He was branded a traitor by the Convention under Maximilien de Robespierre during the Reign of Terror, in 1794. Lavoisier and the other former tax gatherers were formally brought to trial on May 8, 1794. Lavoisier was convicted with summary justice of having plundered the people and the treasury of France, of having adulterated the nation’s tobacco with water, and of having supplied the enemies of France with huge sums of money from the national treasury. Lavoisier, along with 27 of his former colleagues, was guillotined on the same day. Lavoisier’s importance to science was expressed by Joseph Louis Lagrange who lamented the beheading by saying: “Il ne leur a fallu qu’un moment pour faire tomber cette tête, et cent années peut-être ne suffiront pas pour en reproduire une semblable.” (“It took them only an instant to cut off this head, and one hundred years might not suffice to reproduce its like.”)  He was exonerated 18 months later.

I was very fond of chemistry as a boy (my father was a chemistry teacher), and for several years I had a chemistry lab in my bedroom.  It came as a great revelation to me when I was working in the kitchen with my mother, baking a cake, when she explained that once the baking powder was added to the mix you had to work quickly because moistening the powder set off a chemical reaction (an acid plus a carbonate producing carbon dioxide) that would cause the cake to rise, but would peter out if you waited too long before baking. Who knew?  Since then I have always applied my knowledge of chemistry to cooking in one way or another.  For example, red cabbage has a tendency to turn blue when heated because the heat increases alkalinity in the cabbage.  Solution – add an acid (such as vinegar) during the cooking process and the cabbage stays red.

Let’s use one of the best understood chemical processes in cooking, the Maillard reaction, to make a stew.  The Maillard reaction is a non-enzymatic process of browning that is essential to so much cooking. The browning of old, or peeled, fruits and vegetables is caused by enzymes; browning meat and vegetables by frying or baking is not.  The Maillard reaction (browning) occurs when heat is applied to a combination of amino acids and reducing sugars (chemical components of meats and vegetables).  I choose this as a tribute to Lavoisier because oxygen in the molecules plays a key role (“redox” for those who know some chemistry), in browning (and also in the production of flavor changes). In this recipe I am not using any aromatics such as parsley or thyme because I want the Maillard reaction to speak for itself.


Tío Juan’s Classic Beef Stew ©

2 lbs (1 kilo) stewing beef
1 onion peeled and coarsely chopped
1 ½ lbs (750 g) potatoes
1 lb (500 g) carrots peeled and diced
½ lb (250 g) mushrooms (halved or quartered depending on size)
1 leek chopped
2 cloves of garlic minced fine
4 tbsps extra virgin olive oil
2 pints (9.5 dl) water
1 tbsp butter
1 tbsp flour
salt to taste


I use a heavy, large, well seasoned cast iron skillet for this dish – my single most important pan in the kitchen (in fact, I have two). Use a large skillet or heavy pot. For the browning, use as little oil as needed to prevent sticking. My quantities are for a large skillet.

Put one tablespoon of olive oil in your pot, and heat on medium low heat.  Add the onions and leeks. Cook slowly, stirring occasionally, until the onions and leeks are caramel colored. In the last minute or two add the garlic, but do not let it brown.  The Maillard reaction makes garlic bitter. Set aside in a large bowl.

Raise the temperature to medium high. Add another tablespoon of olive oil. Sauté the carrots quickly until they are browning but not burnt. Set aside with the onions and leeks.

Peel and dice the potatoes. (Doing this ahead of time will cause them to brown by an enzymatic action, NOT the Maillard reaction.  You can prevent browning by placing cut potatoes in acidulated water, but in this case having the potatoes wet is undesirable.) Cook the potatoes as you did the carrots. Set aside in the vegetable bowl.

Raise the temperature to high. Add another tablespoon of olive oil. Sauté the mushrooms quickly. You must be quick because you want them to brown without overcooking. Set aside with the other vegetables.

Add the last of the olive oil. Quickly brown the meat on all sides.  Make sure the pieces are deeply browned.  Add to the vegetables.

Reduce the heat to medium.  Add the butter and flour to the pan.  Using a wire whisk, stir the melted butter and flour to blend.  Cook this roux slowly, stirring often, until it becomes caramel colored.

Slowly add the water to the roux whisking constantly. It will be very thick at first but if you whisk well no lumps will form.

Return the meat and vegetables to the pot, add salt to taste, and simmer until the meat is tender (about 1 hour).  If you want the carrots and potatoes to be firmer, reserve them separately and add them to the pot in the last 20 minutes.

Serve in bowls piping hot with crusty bread (yes, the brown crust is due to the Maillard reaction as well!)

Serves 4

[Re-bloggers note: this recipe is copyright ©Tío Juan.  Use it by all means, but credit me.]