IV. CHEMISTRY

1. The Pursuit of Oxygen

“Physics and mathematics,” wrote Edward Gibbon in 1761, “are now on the throne. They see their sisters prostrate before them, chained to their car, or at most adorning their triumph. Perhaps their own fall is not far distant.”24 It was an unlucky prediction; physics is now the queen of the sciences, mathematics is her helpmate, and no man can tell what will come of their union.

Nevertheless, amid all the victories of seventeenth-century mathematics, physics, and astronomy, a young science had emerged from the swaddling clothes of alchemy. A tragic error almost stifled it in its infancy. Following a theory proposed by Johann Becher in 1669, Georg Stahl, professor of medicine and chemistry at Halle, interpreted combustion as the liberation of “phlogiston” from the burning material into the air. (Phlogiston was Greek for inflammable; phlox was Greek for flame, and is our word for a plant whose flowers are sometimes flaming red.) By 1750 most chemists in Western Europe accepted this theory of heat or fire as a substance detached from burning matter. But no one could explain why, if this was so, metals weighed more after burning than before.

Our current explanation of combustion was prepared by the work of Hales, Black, and Scheele on the chemistry of the air. Stephen Hales paved the way by devising a “pneumatic trough,” or air receptacle, into which gases could be collected in a closed vessel over water. He pointed out that gases (which he called “airs”) were contained in many solids, and he described air as “a fine elastic fluid, with particles of a very different nature floating in it.”25 The decomposition of air and water into diverse substances put an end to the agelong conception of air, water, fire, and earth as the four fundamental elements. In the next generation the experiments of Joseph Black (1756) proved that one constituent of air was what, after Hales, he called “fixed air”—i.e., air contained in, and removable from, solid or liquid substances; we now term it carbon dioxide, or “carbonic-acid gas.” Black further cleared the way to the discovery of oxygen by showing experimentally that this gas is contained in human exhalations. But he still believed in phlogiston, and oxygen, hydrogen, and nitrogen were still mysteries.

Sweden contributed lavishly to eighteenth-century chemistry. Torbern Olof Bergman, whom we shall meet again as a pioneer in physical geography, was primarily a chemist, famous and loved as a professor of that science in the University of Uppsala. He was the first to obtain nickel in a pure state and the first to show the importance of carbon in determining the physical properties of carbon-iron compounds. In his relatively short life of forty-nine years he studied, with over thirty thousand experiments, the chemical affinities of fifty-nine substances, and reported his findings in Elective Attractions (1775). He died before completing this task, but meanwhile he had passed on to Scheele his devotion to chemical research.

English historians of science now gallantly concede that a Swedish chemist, Karl Wilhelm Scheele, anticipated (1772) Priestley’s discovery (1774) of what Lavoisier (1779) was the first to call oxygen. Scheele lived most of his forty-three years in poverty. Beginning as an apprentice to an apothecary in Göteborg, he rose no higher than to be a pharmacist in the modest town of Köping. His teacher, Torbern Bergman, obtained a small pension for him from the Stockholm Academy of Science; Scheele spent eighty per cent of it on chemical experiments. He performed most of these at night after the day’s work, and with the simplest laboratory equipment; hence his early death. Yet he covered nearly the whole field of the new science, and defined it with his usual simplicity: “The object and chief business of chemistry is skillfully to separate substances into their constituents, to discover their properties, and to compound them in different ways.”26

In 1775 he sent to the printer a manuscript entitled Chemical Treatise on Air and Fire; its publication was delayed till 1777, but nearly all the experiments it described had been carried out before 1773. Scheele, while holding till his death the belief in phlogiston, laid down the basic proposition that unpolluted atmosphere is composed of two gases: one of these he named “fire-air” (our oxygen), as the main support of fire; the other he called “vitiated air” (our nitrogen), as air that has lost “fire-air.” He prepared oxygen in several ways. In one method he mixed concentrated sulfuric acid with finely ground manganese, heated the mixture in a retort, and collected the resultant gas in a bladder that had been pressed nearly free of air. He found that when the gas so produced was played over a lighted candle, this “began to burn with a larger flame, and emitted such a bright light that it dazed the eyes.”27 He concluded that “fire-air” was the gas that supported fire. “There is little doubt but that he obtained the gas two years before Priestley.”28

This was but a fraction of Scheele’s achievement. His record as a discoverer of new substances is probably unequaled.29 He was the first to isolate chlorine, barium, manganese, and such new compounds as ammonia, glycerine, and hydrofluoric, tannic, benzoic, oxalic, malic, and tartaric acids. His discovery that chlorine would bleach cloth, vegetables, and flowers was put to commercial uses by Berthollet in France and James Watt in England. In further researches Scheele discovered uric acid by analyzing stone in the bladder (1776). In 1777 he prepared sulfuretted hydrogen, and in 1778 molybdic acid; in 1780 he proved that the acidity of sour milk is due to lactic acid; in 1781 he obtained tungstic acid from calcium tungstate (now known as scheelite); in 1783 he discovered prussic (hydrocyanic) acid, without realizing its poisonous character. He produced also arsine gas (a deadly compound of arsenic), and the arsenic pigment now known as Scheele’s green.30 He helped to make photography possible by showing that sunlight reduces chloride of silver to silver, and that the diverse rays that compose white light have different effects upon silver salts. The incredibly fruitful labor of this brief life proved of endless importance in the industrial developments of the nineteenth century.

2. Priestley

Joseph Priestley, rather than Scheele, for a long time received the credit for the discovery of oxygen because he discovered it independently of Scheele, and announced his discovery in 1775, two years before Scheele’s retarded publication. We honor him nevertheless because his researches enabled Lavoisier to give chemistry its modern form; because he was among the pioneers in the scientific study of electricity; and because he contributed so boldly to British thought on religion and government that a fanatical mob burned down his house in Birmingham, and induced him to seek refuge in America. He touched the history of civilization at many points, and is one of its most inspiring characters.

He was born in Yorkshire in 1733, son of a Dissenter cloth-dresser. He studied voraciously in science, philosophy, theology, and languages; he learned Latin, Greek, French, German, Italian, Arabic, even some Syriac and Chaldee. He set up as a Dissenting preacher in Suffolk, but an impediment in his speech lessened the appeal of his eloquence. At twenty-five he organized a private school, whose curriculum he enlivened with experiments in physics and chemistry. At twenty-eight he became tutor in a Dissenting academy at Warrington; there he taught five languages and yet found time for researches that won him a fellowship in the Royal Society (1766). In that year he met Franklin in London, and was encouraged by him to write The History and Present State of Electricity(1767), an admirable survey of the whole subject up to his own time. In 1767 he was appointed pastor of Mill Hill Chapel at Leeds. He recalled later that “it was in consequence of living for some time in the neighborhood of a public brewery that I was induced to make experiments in fixed air”31—the brewery mash emitted carbonic-acid gas. He dissolved this in water, and liked its bubbling tang; this was the first “soda water.”

In 1772 he was relieved of economic worry by appointment to the post of librarian to Lord Shelburne. In the house provided for him at Colne he performed the experiments that won him international renown. He improved upon Hales’s pneumatic trough by collecting over mercury, instead of over water, the gases generated by diverse mixtures. So in 1772 he isolated nitric oxide, nitrous oxide (“laughing gas”), and hydrogen chloride; in 1773 ammonia (independently of Scheele); in 1774 sulfur dioxide; in 1776 nitrogen peroxide. On March 15, 1775, he communicated to the Royal Society a letter announcing his discovery of oxygen. In Volume II of his Experiments and Observations on Different Kinds of Air (1775) he described his method. Using a strong burning lens, he said,

I proceeded … to examine, by the help of it, what kind of air a great variety of substances would yield [when so heated], putting them into … vessels … filled with quicksilver and kept inverted in a basin of the same. With this apparatus, … on the first of August, 1774, I endeavored to extract air from mercurius calcinatus per se [mercuric oxide]; and I presently found that, by means of this lens, air was expelled from it very readily.… What surprised me, more than I can well express, was that a candle burned in this air with a remarkably vigorous flame.32

Noting, like Scheele, that a mouse lived much longer in this “dephlogisticated air” (as he called oxygen) than in the ordinary atmosphere, he thought he might safely sample the new air himself.

My reader will not wonder that, after having ascertained the superior goodness of dephlogisticated air by mice living in it, and the other tests above mentioned, I should have the curiosity to taste it by myself. I have gratified that curiosity by breathing it, drawing it through a glass siphon; and by this means I reduced a large jar full of it to the standard of common air. The feeling of it to my lungs was not sensibly different from common air, but I fancied that my breast felt peculiarly light for some time afterward. Who can tell but that, in time, this pure air may become a fashionable article of luxury? Hitherto only two mice and I have had the privilege of breathing it.33

He predicted some forms of this future luxury:

From the greater strength and vivacity of the flame of a candle in this pure air, it may be conjectured that it might be peculiarly salutary to the lungs in certain morbid cases, when the common air would not be sufficient to carry off the phlogistic putrid effluvium [carbon dioxide] fast enough. But perhaps we may also infer from these experiments that though pure dephlogisticated air [oxygen] might be very useful as a medicine, it might not be so proper for us in the usual healthy state of the body; for as a candle burns out faster in dephlogisticated air than in common air, so we might, as may be said, live out too fast, and the animal power be too soon exhausted, in this pure kind of air.34

Priestley’s experimental work was brilliant with fruitful hypotheses and alert perceptions, but his theoretical interpretations were mostly traditional. Like Stahl and Scheele, he supposed that in combustion a substance, phlogiston, was emitted by the burning material; this substance, in his view, united with one constituent of the atmosphere to form “vitiated air,” or “phlogisticated air” (our nitrogen); the other constituent was in his nomenclature “dephlogisticated air,” which Lavoisier was to name oxygen. While Lavoisier argued that a material in process of combustion absorbed oxygen from the air instead of expelling phlogiston into it, Priestley to the end of his life retained the old conception.

In 1774 he traveled with Lord Shelburne on the Continent, and told him of the oxygen experiments. In 1780 Shelburne retired him with an annuity of £ 150. Priestley settled in Birmingham as junior minister of a large Dissenting congregation known as the New Meeting Society. He joined James Watt, Josiah Wedgwood, Erasmus Darwin, Matthew Boulton, and others in a “Lunar Society” that discussed the latest ideas in science, technology, and philosophy. He was popular with nearly all classes, admired for his cheerful spirit, his modesty and generosity, and “the unspotted purity of his life.”35 But some of his neighbors questioned his Christianity. In Disquisitions relating to Matter and Spirit (1777) he reduced everything, even the soul, to matter. This, he insisted, was perfectly orthodox,

it being well known to the learned … that what the ancients meant by an immaterial being was only a finer kind of what we should now call matter; something like air or breath, which first supplied a name for the soul.. . . Consequently the ancients did not exclude from mind the property of extension and local pressure. It had, in their idea, some common properties with matter, was capable of being united with it, of acting and being acted upon by it.… It was therefore seen that … the power of sensation or thought … might be imparted to the very grossest matter, … and that the soul and body, being in reality the same kind of substance, must die together.36

In a further publication of the same year, The Doctrine of Philosophical Necessity Illustrated, Priestley, following Hartley and Hume, enthusiastically denied the freedom of the will. And in a History of the Corruptions of Christianity (1782), he rejected miracles, the Fall, the Atonement, and the Trinity; all these doctrines he considered to be “corruptions” developed in the evolution of Christianity; they were not to be found in the teachings of Christ or the twelve Apostles. All that was left of Christianity in Priestley was the belief in God, based on the evidences of divine design. Not quite reconciled to mortality, he suggested that at the Last Day God would re-create all the dead. His real hope, however, was not in a heaven above but in a utopia that would be built on this earth by the victory of science over superstition and ignorance. Seldom has the eighteenth-century religion of progress been more fervently expressed:

All knowledge will be subdivided and extended; and knowledge, as Lord Bacon observes, being power, the human powers will in fact be increased; nature, including both its materials and its laws, will be more at our command; men will make their situation in this world abundantly more easy and comfortable; they will probably prolong their existence on it, and will daily grow more happy, each in himself, and more able (and, I believe, more disposed) to communicate happiness to others. Thus, whatever was the beginning of this world, the end will be glorious and paradlsaical beyond what our imaginations can now conceive.37 … Happy are they who contribute to diffuse the pure light of this everlasting gospel.38

Part of this glorious progress, in Priestley’s vision, was to be political, and would be based upon a simple humanitarian principle: “The good and happiness of the … majority of the members of any state is the great standard by which everything relating to that state must finally be determined”;39 here Bentham, according to Bentham, found one source of his utilitarian philosophy. The only just government, said Priestley, is one that aims at the happiness of its citizens, and it is quite consistent with Christianity that an obviously unjust government should be overthrown by the people. To St. Paul’s caution that “the powers that be are ordained of God” Priestley replied that “for the same reason the powers which will be will be ordained of God also.”40

It was natural that such a rebel should sympathize with the colonies in their protest against taxation without representation. Still more warmly did he acclaim the French Revolution. When Burke denounced it Priestley defended it; Burke, in Parliament, branded him as a heretic. Some of Priestley’s friends shared his radical views. On July 14, 1791, the “Constitutional Society of Birmingham” met in the Royal Hotel to celebrate the anniversary of the fall of the Bastille. Priestley did not attend. A crowd gathered before the hotel, listened to its leaders’ attacks upon heretics and traitors, and stoned the hotel windows; the banqueters fled. The crowd moved on to Priestley’s house, and joyously burned it down, including his laboratory and instruments, his library and manuscripts. Then for three days it ranged through Birmingham, swearing to kill all “philosophers”; terrified citizens scrawled on their windowpanes, “No philosophers here.” Priestley fled to Dudley, then to London. Thence on July 19 he addressed a letter to the people of Birmingham:

MY LATE TOWNSMEN AND NEIGHBORS,

After living with you eleven years, in which you had uniform experience of my peaceful behavior in my attention to the quiet duties of my profession, and those of philosophy, I was far from expecting the injuries which I and my friends have lately received from you.… Happily the minds of Englishmen have a horror of murder and therefore you did not, I hope, think of that.… But what is the value of life when everything is done to make it wretched? …

You have destroyed the most truly valuable and useful apparatus of philosophical instruments.… You have destroyed a library … which no money can repurchase except in a long course of time. But what I feel far more, you have destroyed manuscripts which have been the result of the laborious study of many years, and which I shall never be able to recompose; and this has been done to one who never did, or imagined, you any harm.

You are mistaken if you imagine that this conduct of yours has any tendency to serve your cause, or to prejudice ours.… Should you destroy myself as well as my house, library, and apparatus, ten more persons, of equal or superior spirit and ability, would instantly spring up. If those ten were destroyed, an hundred would appear. …

In this business we are the sheep and you the wolves. We will persevere in our character, and hope you will change yours. At all events, we return you blessings for curses, and pray that you may soon return to that industry, and those sober manners, for which the inhabitants of Birmingham were formerly distinguished.

I am, your sincere well-wisher,

J. PRIESTLEY.41

Nevertheless he sued the city for damages, estimating his loss at £4,500; Charles James Fox helped his suit; Birmingham awarded him £ 2,502. He tried to establish a new domicile in England, but churchmen, royalists, and his fellows in the Royal Society shunned him.42 The French Académie des Sciences, through its secretary, Condorcet, sent him an offer of a home and laboratory in France. On April 8, 1794, aged sixty-one, he emigrated to America. He made his new home in the town of Northumberland, in Franklin’s Pennsylvania, on the banks of that lovely Susquehanna River about which Coleridge and Southey were soon to dream. He resumed his experiments, and discovered the composition of carbon monoxide. He was welcomed by learned societies, and was offered the chair in chemistry at the University of Pennsylvania. In 1796 he delivered before the Universalists of Philadelphia a series of discourses on “The Evidences of Christianity”; his audience included Vice-President John Adams and many members of Congress. From those meetings a Unitarian Society took form. Two years later Timothy Pickering, Secretary of State under President Adams, proposed to deport Priestley as an undesirable alien. The election of Jefferson (1800) ended Priestley’s insecurity, and he was allowed four years of peace. In 1803 he wrote his last scientific paper, still defending phlogiston. He died at Northumberland on February 6, 1804. In 1943 the Pennsylvania legislature designated his home as a national memorial.

While Thomas Paine took up Priestley’s campaign as a rebel Christian, Henry Cavendish pursued the chemistry of gases. Son of a lord, nephew of a duke, Cavendish at forty inherited one of the greatest fortunes in England. Timid, hesitant in speech, careless of dress, he lived as a recluse in his laboratory at Clapham Common, London, and made no overtures to fame. His research was distinguished by meticulous measuring and weighing of all materials before and after an experiment; these measurements enabled Lavoisier to formulate the principle that in chemical changes the amount of matter remains constant.

In 1766 Cavendish reported to the Royal Society his experiments on “factitious air”—i.e., gas derived from solids. By dissolving zinc or tin in acids he produced what he called “inflammable air”; he identified this with phlogiston; we now call it hydrogen; Cavendish was the first to recognize this as a distinct element, and to determine its specific gravity. In 1783, following up an experiment by Priestley, he found that when an electric spark was passed through a mixture of common air and “inflammable air,” part of the mixture was condensed into dew; he concluded from this electrolysis that water is composed of 2.014 volumes of “inflammable air” to one volume of Priestley’s “dephlogisticated air”—or, as we now say, H20; this was the first definite proof that water is a compound, not an element. (James Watt independently suggested the same composition of water in that same year 1783.) Again applying an electric spark to a mixture of hydrogen with common air, Cavendish obtained nitric acid, and concluded that pure air is composed of oxygen and nitrogen. (Daniel Rutherford of Edinburgh had discovered nitrogen as a distinct element in 1772.) Cavendish admitted a small residue which he could not explain, but which he calculated to be 0.83 per cent of the original amount. This remained a mystery till 1894, when Rayleigh and Ramsay isolated this part, now called argon, as a separate element, and found it to be by weight 0.94 per cent common air. Cavendish’s scales were justified.

3. Lavoisier

Meanwhile, across the Channel, a group of enthusiastic researchers gave France the lead in the new science, and gave chemistry essentially the form that it has today. At their source stood Guillaume Rouelle, distinguished for his work on the chemistry of salts, but best known for the lecture courses in which he taught chemistry to rich and poor, to Diderot and Rousseau, and to the greatest chemist of them all.

Antoine Lavoisier had the advantage or handicap of being born to wealth (1743). His father, an advocate in the Paris Parlement, gave the boy all the education then available, and bequeathed to him, then twenty-three years old, 300,000 livres. Such a fortune could have aborted a literary career, but it was a help in a science that demanded expensive apparatus and long years of preparation. Sent to a law school, Antoine escaped from it into mathematics and astronomy, and attended Rouelle’s lectures in the auditorium of the Jardin du Roi. Nevertheless he completed his law studies, and then accompanied Jean Guettard in making mineralogical tours and maps of France. In 1768 he was elected to the Académie des Sciences, which at that time included Buffon, Quesnay, Turgot, and Condorcet. A year later he joined the farmers general in their unpopular business of collecting excise taxes to reimburse themselves for their advances to the government. He paid 520,000 livres for a third interest in one of the sixty shares of the ferme générale; in 1770 he raised this to a full share. In 1771 he married Marie Paulze, daughter of a rich farmer general. He spent part of his time now in traveling through the provinces, collecting revenue, tax data, and geological specimens. His wealth financed a great laboratory and costly experiments,III but it brought him to the guillotine.

He took an active part in public affairs. Appointed (1775) régisseur des poudres, commissioner of gunpowder, he increased the production and improved the quality of that explosive, making possible its large-scale export to the American colonies and the victories of the French Revolutionary armies. “French gunpowder,” said Lavoisier in 1789, “has become the best in Europe.… One can say with truth that to it North America owes its liberty.”43 He served on a variety of official boards, national or municipal, and met with versatile intelligence diverse problems of taxation, coinage, banking, scientific agriculture, and public charity. As a member of the provincial assembly at Orléans (1787) he labored to better economic and social conditions. During the critical food shortage of 1788 he advanced his own money to several towns for the purchase of grain. He was a public-spirited man who kept on making money.

Amid all these activities he did not cease to be a scientist. His laboratory became the most complex and extensive before the nineteenth century: 250 instruments, thirteen thousand glass containers, thousands of chemical preparations, and three precision balances that later helped to determine the gram as the unit of weight in the metric system. Weighing and measuring were half the secret of Lavoisier’s discoveries; through them he changed chemistry from a qualitative theory to a quantitative science. It was by careful weighing that he proved Stahl’s phlogiston to be an encumbering myth. That myth had assumed the existence of a mysterious substance which in combustion left the burning material and entered the air. On November 1, 1772, Lavoisier submitted to the Académie des Sciences a note that read:

About eight days ago I discovered that sulfur in burning, far from losing weight, rather gains it; that is to say, that from a pound of sulfur may be obtained more than a pound of vitriolic acid, allowance being made for the moisture of the air. It is the same in the case of phosphorus. The gain in weight comes from the prodigious quantity of air which is fixed [i.e., absorbed by the burning matter] during the combustion, and combines with the [vitriolic] vapors. This discovery, which I have established by experiments that I consider decisive, has made me believe that what is observed in the combustion of sulfur and phosphorus may equally well take place in the case of all those bodies which gain weight on combustion or calcination.44

Instead of the burning material giving something to the air, it took something from the air. What was this something?

In the fall of 1774 Lavoisier published an account of further experiments. He put a weighed quantity of tin into a weighed flask large enough to contain considerable air; he sealed the flask, and heated the whole till the tin had been well oxidized. Having allowed the system to cool, he found that its weight remained unchanged. But when he broke the seal air rushed into the flask, indicating that a partial vacuum had been created in the flask. How? Lavoisier saw no other explanation except that the burning tin had absorbed into itself a part of the air. What was this something?

In October, 1774, Lavoisier met Priestley in Paris. Priestley told him of the experiments he had made in August, which Priestley still interpreted as showing an escape of phlogiston from the burned substance into the air. On April 26, 1775, Lavoisier read to the Académie a memoir reporting the experiments that had led him to view combustion as the absorption, by a burning substance, of a mysterious element from the air, which he provisionally called air éminemment pur. Like Priestley, he had discovered oxygen; unlike Priestley, he had overthrown the phlogiston myth. Not till 1779 did he coin, for the combustible element in the air, the name oxygène, from Greek words meaning “acid-generator,” for Lavoisier mistakenly believed that oxygen was an indispensable constituent of all acids.

Like Priestley, Lavoisier observed that the kind of air absorbed by metals in combustion is also the kind that best supports animal life. On May 3, 1777, he presented to the Académie a paper “On the Respiration of Animals.” “Five sixths of the air we breathe,” he reported, “is incapable of supporting the respiration of animals, or ignition and combustion; … one fifth only of the volume of atmospheric air is respirable.” He added that “an air which has for some time served to support this vital function has much in common with that in which metals have been calcined [oxidized]; knowledge of the one [process] may naturally be applied to the other” Lavoisier thereupon founded organic analysis by describing respiration as the combination of oxygen with organic matter. In this process he noted a liberation of heat, as in combustion; and he further confirmed the analogy of respiration and combustion by showing that carbon dioxide and water are given off (as in respiration) by the burning of such organic substances as sugar, oil, and wax. The science of physiology was now revolutionized by the spreading interpretation of organic processes in physicochemical terms.

The multiplication of experiments, the growth of chemical knowledge, and the abandonment of the phlogiston theory required a new formulation, and a new nomenclature, for the burgeoning science. The Académie des Sciences appointed Lavoisier, Guyton de Morveau, Fourcroy, and Berthollet to attempt this task. In 1787 they published Méthode d’une nomenclature chimique. Old-fashioned names like powder of algaroth, butter of arsenic, and flowers of zinc were discarded; dephlogisticated air became oxygen; phlogisticated air became azote, then nitrogen; inflammable gas became hydrogen; fixed air became carbon acid gas; calcination became oxidation, compounds were named from their components. A table of “simple substances” listed thirty-two elements known to Lavoisier; chemists now list ninety-eight. Most of the terms adopted in the Méthode are standard in chemical terminology today. Lavoisier presented the new nomenclature, and summed up the new science, in his Traité élémentaire de chimie; this appeared in 1789, and marked another revolution—the end of Stahl’s phlogiston and Aristotle’s elements.

Lavoisier himself was a victim of the French Revolution. He had shared in the efforts to avoid it, and in the evils that brought it on. In the decade that prepared it he served zealously on commissions to study and correct abuses in prisons and hospitals. To Comptroller General Laurent de Villedeuil he presented (1787) a memoir listing nine factors in the exploitation of the peasantry. His words were especially honorable coming from a millionaire owner of land:

Let us be bold enough to say that … until the reign of Louis XVI the people counted for nothing in France; it was only the power, the authority, and the wealth of the state that were considered; the happiness of the people, the liberty and well-being of the individual, were words that never fell upon the ears of our former rulers, who were not aware that the real object of government must be to increase the sum total of enjoyment, happiness, and welfare of all its subjects.… The unfortunate farmer groans in his cottage, unrepresented and undefended, his interests cared for by none of the great departments of the national administration.45

Lavoisier was chosen to represent the Third Estate at the provincial assembly that met at Orléans in 1787. There he offered a measure for abolishing the corvée and for maintaining the roads not by the forced labor of the peasantry but by taxes levied onallclasses; the nobility and the clergy defeated this proposal. He recommended a system of social security by which all Frenchmen who so wished would contribute to support their old age; this too was defeated. In a memoir addressed to the government in 1785 he laid down the principle that the coming States-General should have full legislative power, the king to be merely its executive agent; that it should be convoked regularly; that taxation should be universal, and the press free:46 Lavoisier was unquestionably one of the most enlightened members of the French bourgeoisie, and probably his proposals expressed part of its political strategy.

He was also one of the leading members of the ferme générale, which was the object of almost universal resentment. From 1768 to 1786 his profits as a farmer general had averaged 66,667 livres per year, an annual rate of 8.28 per cent; he may have been right in considering this a reasonable return for the labor and risks involved. It was at his suggestion that chief minister Calonne, in 1783–87, built a wall around Paris to check the smugglers who were evading tolls; the wall and the new customshouses and barriers cost thirty million livres, and evoked widespread condemnation; the Duc de Nivernois proclaimed that the originator of the scheme should be hanged.

Lavoisier supported the Revolution in 1789, when it was still under control by the middle classes. A year later he felt that it was moving toward excess, violence, and war, and he pleaded for restraint. In November some employees of the ferme généralepublished a pamphlet accusing the ferme of embezzling their pension fund. “Tremble,” they wrote, “you who have sucked the blood of the unfortunate.”47 In 1791 Marat began a personal campaign against Lavoisier. The “Friend of the People” had published in 1780Recherches physiques sur le feu, in which he claimed to have made visible the secret element in fire; Lavoisier had refused to take the claim seriously; Marat had not forgotten. In his periodical, Ami du peuple, January 27, 1791, Marat denounced the chemist-financier as a charlatan with a fat income, a man “whose only claim to public recognition is that he put Paris in prison by cutting off the fresh air with a wall that cost the poor 33 million livres.… Would to Heaven that he had been strung up to the lamppost.”48 On March 20, 1791, the Constituent Assembly abolished the ferme générale.

Next to be attacked was the Académie des Sciences, for all institutions surviving from the Old Regime were suspected of counterrevolutionary sympathies. Lavoisier defended the Académie, and became the chief target. On August 8, 1793, the Académie was ordered to disband. At its last meeting the roster was signed by, among others, Lagrange, Lavoisier, Lalande, Lamarck, Berthollet, and Monge. Each now went his own way, hoping that the guillotine would not find him.

In the same month Lavoisier, inspired by the ideas of Condorcet, submitted to the Convention a plan for a national system of schools. Primary education was to be free for both sexes “as a duty that society owes to the child.” Secondary education, also open to both sexes, was to be expanded by the establishment of technical colleges throughout France. A month later his rooms were ransacked by governmental agents; among the letters found there, from Lavoisier’s friends, were some that condemned the Revolution and spoke hopefully of foreign armies that would soon overthrow it; other letters showed Lavoisier and his wife planning to escape to Scotland.49 On November 24, 1793, thirty-two former farmers general, including Lavoisier, were arrested. His wife moved every influence to effect his release; she failed, but was allowed to visit him. In prison he continued to work on his exposition of the new chemistry. The financiers were accused of having charged excessive interest, of having adulterated tobacco with water, and of absorbing 130 million livres in illegal profits. On May 5, 1794, they were summoned before the Revolutionary Tribunal. Eight were acquitted; twenty-four, including Lavoisier, were condemned to death. When the presiding judge was asked to commute the sentence on the ground that Lavoisier and some others were savants of value to the state, he was reported to have answered, “The Republic has no need of savants”; but there is no convincing evidence for this tale.50 Lavoisier was guillotined on the very day of the sentence, May 8, 1794, on what is now the Place de la Concorde. Lagrange is said to have commented, “It took only a moment to cut off his head, and a hundred years may not give us another like it.”51

All the property of Lavoisier and his widow was confiscated to help repay the Republic for the 130,000,000 livres allegedly owed by the ferme générale to the state. Mme. Lavoisier, penniless, was supported by an old servant of the family. In 1795 the French government repudiated the condemnation of Lavoisier; her property was restored to Mme. Lavoisier, who survived till 1836. In October, 1795, the Lycée des Arts held a funeral service in Lavoisier’s memory, with Lagrange delivering the eulogy. A bust was unveiled bearing the inscription “Victim of tyranny, respected friend of the arts, he continues to live; through his genius he still serves humanity.”52

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