Chemical Sciences Research Paper

1. Ancient Technologies

From very remote times, people have been using techniques and processes which we would call chemical, involving careful control, as part of a craft or art passed from father to son, mother to daughter, or master to apprentice. Indeed the word ‘chemistry’ is supposed to come from an ancient Egyptian word ‘chem’ meaning earthy: the Arabic definite article ‘Al’ was added to yield our ‘alchemy’, and dropped to give ‘chymistry’ and then by 1700, ‘chemistry.’ Early technologies, culminating in triumphs such as the making of porcelain and Japanese swords, include features we would regard as magical; but since the course of chemical reactions depends upon the purity of components, those involving natural products are hard to predict and to repeat. Recourse to prayers, incantations, and curious additives should not amaze us.

2. Metallurgy, Alchemy, And Pharmacy

Alchemy, with its objective of converting base metals into gold, which chemist-historians portrayed as absurd or dishonest, was not unreasonable. Nature was believed to be perfecting metals within her womb, and the alchemist was simply speeding up the process. If everything was composed, as Aristotle believed, of the four elements Earth, Water, Air, and Fire in different proportions, then changing these ratios would transform one substance into another, and lead might become gold. If, alternatively, Democritus and Epicurus were correct in believing that in appearance there were colors, smells, and tastes, but in reality atoms and void; then because lead, gold, and everything is made up of different arrangements of these ultimately similar atoms (or ‘corpuscles’), again conversions are possible.

Alchemy began in Egypt and Babylonia, and also in China: with emphasis both upon making gold (or maybe something resembling it) using an elixir to expedite the process, and of prolonging and enhancing life by giving humans the noble and permanent qualities of gold. Pharmacy grew out of trial and error, but in the West the maverick Swiss doctor calling himself Paracelsus (1493–1541) brought alchemy into it. He introduced metallic compounds into previously herbal medicine, notably for the treatment of the new disease, syphilis, which was ravaging Europe. He publicly burnt the books of the great Greek physician, Galen, and saw chemical study as essential for medicine. His career outraged the medical establishment, but the powerful and dangerous new remedies proved irresistible to doctors and patients, and medical schools became centers for chemistry.

3. The First Chemical Theories

Until the mid-twentieth century, it was believed that alchemy was abandoned by the rational thinkers of the Scientific Revolution; especially Robert Boyle (1627– 91) and Isaac Newton (1642–1727). Close examination of their manuscripts (Principe 1998) shows that both of them were in fact adepts, copying out and trying alchemical recipes, and believing that they were well on the way to a transmutation. But they were also adherents to the atomic view of matter, seeing hard and indestructible corpuscles or particles as fundamental. These formed very stable primary mixts, such as iron, gold, or sulfur, which in turn combined with each other. Unlike gravity which was universal, chemical affinity was elective: some substances reacted together, others did not. J. W. Goethe wrote a novel, Elective Affinities (1809) exploring chemical and human bonding; chemists in eighteenth-century Germany and Sweden (the center of chemical activity) drew up tables of affinity in attempting to predict the outcome of reactions.

From Germany also came the first chemical paradigm. G. H. Stahl (1660–1734) proposed that everything which would burn contained ‘phlogiston’ (Greek, flammable): this idea brought order into chemical understanding, whereas atomic ideas were vague and untestable. Moreover, in Germany Lorenz Croll in 1778 began the first chemical journal, Chemische Annalen, bringing into being a chemical community there (Hufbauer 1982). His example was followed in France and England by Antoine Lavoisier and William Nicholson.

4. Lavoisier’s Revolution

Lavoisier (1743–94) was a wealthy man, prominent in the privatized tax system of France; his spare time he devoted to chemistry, in a splendidly equipped laboratory. Becoming a member of the Royal Academy of Sciences, the small salaried body charged with scientific research, he resolved to reform the language and theory of chemistry. As in Carl Linnaeus’ botany, names should be international, clear, and free from changeable theory: while phlogiston should be replaced as incoherent. Stahl saw phlogiston emitted in burning; Lavoisier by contrast (in a classic paradigm shift) saw something absorbed from the air, leading to an increase in weight. He drew upon the work of Joseph Priestley (1733–1804), who had isolated ‘vital’ or ‘eminently respirable’ air in a British tradition of work on gases. Lavoisier christened this substance ‘oxygen’ (Greek, sour) because he believed that it was also responsible for acidity (generalizing from analyses of nitric and sulfuric acids). Water was a compound of oxygen with another gas, hydrogen: such elements were the basis of chemistry, rather than the hypothetical corpuscles which might concern physicists, or the Earth, Water, Air, and Fire with which Priestley’s friend Thomas Jefferson (1743–1826) structured his book on Virginia. In 1794 Lavoisier was executed as a tax profiteer during Robespierre’s Reign of Terror, while the left-wing views of Priestley (who continued to disagree with him over phlogiston) led to his exile in Pennsylvania. But their new and exciting chemistry survived and prospered (Bensaude-Vincent and Abbri 1995, Knight and Kragh 1998).

5. Electricity And Chemistry

In 1799 Alessandro Volta (1745–1827) showed that electricity was generated when two metals were dipped into water; there was no need for any animal tissue, as Luigi Galvani (1737–98) had supposed. His paper was an alarm bell, as Humphry Davy (1778–1829) put it, and chemists everywhere repeated and extended the experiments. But results were confusing until in 1806

Davy did the careful experiments confirming his intuition that pure water is decomposed electrically into oxygen and hydrogen only. Just as Newton had found that gravity was the force behind planetary motions, so Davy inferred that electricity and chemical affinity were manifestations of one power. In 1807 he used this insight in isolating the light and reactive metals potassium and sodium, and (putting Britain back on the chemical map) went on to demonstrate, with chlorine, that Lavoisier had been wrong about acidity.

Davy had been appointed to the newly-founded Royal Institution in London’s fashionable West End, where he proved himself a lecturer of enormous attractiveness, making professing a performance art (Golinski 1992, Knight 1998). The fees which men and women paid to join, and hear him, supported a research laboratory in the basement. Davy became one of the first people in Britain to make a living out of chemical research, which had previously perforce been a hobby for an aristocrat like Boyle, a minister of religion like Priestley, or a doctor like Galvani. At the Royal Institution, Davy trained (in a kind of informal apprenticeship) his successor, Michael Faraday (1791–1867), and the pursuit of Davy’s insight that chemical affinity was electrical continued there.

With Lavoisier, chemistry had acquired an exact language, closer to algebra than to the evocative terms of the alchemists; and it had testable theories, for example of acidity. It is the science of the secondary qualities, of colors, smells, and tastes; it promised to be useful (chlorine for disinfecting and bleaching, for example, and oxygen for chest complaints); and it proved popular everywhere. With its connection to electricity, it became the dynamic fundamental science, concerned not just with matter but also with force; there was as yet no unified science of physics. Mechanical explanations seemed shallow; while chemistry’s connections with heat, light, and electricity went deep.

6. A Mature Science

1. J. Berzelius (1779–1848) in Sweden used the unsystematic Davy’s insight to create a structure for chemistry, ‘dualism,’ based on the idea that every compound had a positive and a negative part. He also picked up John Dalton’s idea that each element was composed of atoms, identical to each other and different from those of other elements: Berzelius arranged these in an electrochemical series from oxygen, the most negative, to potassium. The number of elements known steadily grew through the century with improvements in chemical analysis.

Berzelius trained a number of chemists by having them to stay in his house, where Anna the housekeeper washed up dishes and flasks. But in the 1820s Justus Liebig (1803–73) at the University of Giessen launched the first graduate school for turning out a stream of chemists with Ph.D. degrees (Brock 1997, Morrell 1997). Liebig’s success depended upon his having perfected apparatus for analyzing organic compounds; his students usually did their research on some natural product, and published it in the journal which became called Liebigs Annalen after its editor. They found jobs, particularly in the dye industry (Fox and Nieto-Galan 1999) and in pharmacy which were both becoming based in science rather than craft skills; many went to England, a rich country with a poor educational system. With the collapse of Napoleon’s empire in 1815, the University of Berlin had emerged dedicated to research and teaching (Wissenschaft und Bildung), and the various German states began to compete in their opera houses and universities. They followed Giessen, building better laboratories and bidding for star chemists. Schools began teaching chemistry, textbooks were needed (Lundgren and Bensaude-Vincent 2000), and academic careers opened up in a field now largely separated from medicine. Universities in Britain and the USA followed the German model, usually demanding German research experience from professorial candidates.

In the 1850s chemists could agree about what things were made of, but not about formulae. Dalton had supposed that water must have the simplest possible formula, HO; Davy and others, notably Amadeo Avogadro (1776–1856), went for our H O formula because two volumes of hydrogen combine with one of oxygen. An atom of oxygen thus weighed either 8 or 16 times as much as one of hydrogen, and such uncertainties ran through the whole list of elements. In 1860 August Kekule (1829–96), a pioneer in working out chemical structures such as that of benzene, called for an end to this confusion through an international conference, which met in Karlsruhe. It was poorly organized, but afterwards chemists came to accept the reformulation of Avogadro’s arguments by Stanislao Cannizzaro (1826–1910). With agreed atomic weights, tabular arrangement of the elements became possible; and the most successful was the Periodic Table of Dmitri Mendeleev (1834–1907).

His predictions of the properties of some hitherto undiscovered elements were startlingly accurate; and with the table (as he hoped) the student had to remember fewer brute facts. From its position an element’s properties would be known. It is striking that so many bright ideas, from Dalton via Cannizzaro to Mendeleev, came from people on the periphery rather than in the great scientific centers.

7. The Fragmentation Of Chemistry

In death, we rot: for we (and animals and plants) are then subject to chemical reactions which go differently while we are alive. Most people believed in a vital force which maintained life. It is claimed that Friedrich Woehler (1800–82), pupil of Berzelius and friend of

Liebig, destroyed this vitalism when in 1828 he synthesized urea. In fact the chief interest in this reaction was that ammonium cyanate and urea turned out to have the same atomic constitution: their different properties were the result of different arrangements (Brooke 1995). So the story has more to do with understanding molecular structure; but the synthesis, and the work of Liebig and his students in analysis, showed that no gulf separated organic and inorganic worlds. Nevertheless, by 1848 when Berzelius died, it was clear that dualism did not fit organic compounds well, and as the chemical community grew it was convenient to separate organic chemistry, based upon carbon, from the inorganic branch. The expansion of universities led to new professorships and laboratories devoted to the specialism of organic chemistry, from which in the twentieth century emerged biochemistry.

Chemists had relied upon balances, test-tubes, condensers, blowpipes, and other apparatus difficult to manipulate. The chemist had to think with his (or occasionally her) fingers, and was proud of skills in glassblowing. Chemistry was essentially experimental, exciting and often dangerous, attractive. Then in 1860 came collaboration between Robert Bunsen, inventor of the controllable gas burner, and the physicist G. R. Kirchhoff, who found that elements heated to a high temperature have characteristic spectra. Analysis could be done by physical methods, and this optical spectroscopy was the first of what is now an armory of such techniques which has transformed the appearance of chemical laboratories (Morris and Travis, in Krige and Pestre 1997, pp. 715–40).

About the same time the new science of thermodynamics, based on energy and its transformations, brought together into classical physics sciences which had been separate, or had been part of the empire of chemistry, Davy and Faraday had been pioneers in what became a new specialism, physical chemistry, investigating energy changes in reactions, and the mechanisms, rates, and reversibility of processes. The leaders here were Wilhelm Ostwald (1853–1932) and J. H. Van’t Hoff (1852–1911) who launched a journal, and promoted academic positions and laboratories. The new profession of chemical engineering was closely linked to the rise of physical chemistry. Whereas early in the nineteenth century chemists had been called in only as consultants or trouble shooters when something went wrong, by the end of it they were employed full-time (Bud and Roberts 1984). In industry, intellectual property belongs generally to the company and not the individual, and is secured by patents (Travis et al. 1998).

8. The Reduction Of Chemistry

The nineteenth century was the heyday of chemistry, the golden age in which it came to maturity and seemed fundamental. The chemist and spectroscopist William Crookes (1832–1919) followed Faraday in studying cathode rays, but J. J. Thomson in 1897 identified them as composed of subatomic corpuscles, soon named ‘electrons.’ The subsequent nuclear atomic model of Ernest Rutherford (1871–1937)—for whom all science was physics or stamp-collecting— and Niels Bohr (1885–1962) accounted not only for spectra, but also for the Periodic Table. Chemistry became a branch of physics (Nye 1996); the properties of gold could in principle be calculated from data about protons, neutrons, and electrons, though in practice the chemistry laboratory is essential. This meant that chemistry lost its glamor; the chemist was as ubiquitous as ever, an essential member of the teams or groups so characteristic of twentieth-century science, but playing a service role (Knight 1995).

The number of chemists has continued to grow, as has the number of new substances unknown in nature which they have synthesized. Davy wrote of the chemist being a godlike creator, and this creativity is nowadays celebrated by chemists such as Roald Hoffmann. The engineer or architect must remember the law of gravity, but to mourn that architecture has been reduced to physics would be absurd: like the poet or the painter, the chemist has to work within constraints, but that is a feature of life—indeed making creativity possible (Hoffmann and Torrance 1993).

Hoffmann, born in Poland, surviving World War II, escaping to the USA, learning chemistry there, and doing research which brought him a Nobel Prize, exemplifies another trend. Chemistry reached the West via Islam. By the eighteenth and nineteenth centuries, it was a European science, with Germany the most important center by 1900. Papers in German journals, and research experience in Germany, counted high in any pecking order; but already the USA was becoming a major power in science. There in 1916 G. N. Lewis proposed the electronic theory of chemical combination, much developed by his pupil Linus Pauling. Since 1945 the USA has been the center of things, making the English language and publication in US journals the key to prestige in research. Two world wars, and Hitler’s coming to power between them, are part of the reason for this; equally important has been American prosperity, itself dependent on science. Chemistry has steadily gone West.

9. The Status Of Chemistry

Davy and Liebig (Rossiter 1975) wrote famous books on agricultural chemistry, and in the nineteenth century chemical fertilizers and pesticides were unequivocally welcomed in a Europe of food shortages. Lavoisier improved French gunpowder, and later chemists produced high explosives making possible engineering achievements and also formidable weapons. All these things were seen as benefits. National chemical societies, their academic and professional aspects sometimes in tension, were formed and enjoyed prestige (Russell et al. 1977). Although pollution from new chemical industries (as from older ones like tanning) was palpable and led to legislation, the expectation was that the chemists would be able to cure it. It did not happen: Rachel Carson’s book The Silent Spring (1962) alerted the world to the dangers. So in the late twentieth century, despite successes such as plastics, and the array of new drugs available for medicine, chemistry is seen as boring and its applications as threatening. Chemists feel misunderstood and underappreciated.

Twentieth-century chemistry is dominated not only by universities in the Giessen tradition, but also by big-spending international companies with research laboratories, now turning towards biotechnology (Galentos and Sturchio, and Kevles, in Krige and Pestre 1997, pp. 227–52, 301–18) and by the military. Research is carried on no longer by a Woehler or a Crookes, on their own or with an assistant, but by teams of people possessing various skills. Chemistry has been taught in an impersonal way, with less handson experiment in a world more conscious of health and safety.

This is a strange eventful history, which was until the mid-twentieth century mainly written by participants who looked for progress. They had the advantage of being familiar with chemicals and apparatus; but professional historians of science have come to look more closely at contexts and careers. The history which emerges deserves to be known beyond the world of chemists.

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