IELTS Academic Reading Practice Test 290

In the second half of the eighteenth century, a group of friends and acquaintances in the English Midlands began meeting to discuss experiments, manufactures and medicine. They had no rulebook, no officers, no subscription and no building of their own, and they kept no minutes. Because of this informality, historians have found it surprisingly difficult to say exactly when the group began or who belonged to it. Yet this loose circle, remembered as the Lunar Society of Birmingham, brought together some of the most inventive figures of the age. Its conversations helped to shape ideas that would transform industry, chemistry and medicine.

The name came from the timing of the meetings. Members gathered once a month, on the Monday nearest the full moon, so that those who had come from outside Birmingham could ride home afterwards along roads that were otherwise unlit. A joke about the moon stuck: members are said to have called themselves the Lunaticks, and the modern name is a later and more dignified version.

The leading figure in the group's early years was Matthew Boulton, who had established a manufactory at Soho, a few miles from Birmingham, in the 1760s. Another was Erasmus Darwin, a physician and poet who practised in Lichfield and later in Derby, and whose curiosity ranged across botany, medicine and mechanics. A third was William Small, a Scottish doctor who had taught natural philosophy at the College of William and Mary in Virginia before returning to Britain and settling in Birmingham in 1765. With John Whitehurst, a clockmaker from Derby, and James Keir, a chemist, these men formed the core of the circle.

Others joined or drifted in over the years. Josiah Wedgwood, whose pottery works lay in Staffordshire, became a close friend of Darwin and Boulton and benefited from their advice on canals and on the chemistry of clays and glazes. James Watt, the engineer from Glasgow, settled in Birmingham in 1774 and entered into partnership with Boulton the following year. The firm of Boulton and Watt went on to manufacture steam engines. In 1780 Joseph Priestley, a minister and natural philosopher already famous for his work on electricity and gases, moved to Birmingham to take charge of a congregation there. The physician and botanist William Withering and the banker Samuel Galton also belonged to the circle.

Meetings were informal gatherings at members' houses rather than lectures. Someone would show a mineral, a new instrument or the result of an experiment; a letter from a correspondent abroad might be read aloud; a problem in chemistry or engineering would be argued over. The conversation was as likely to concern canals, coinage or the glazing of pottery as abstract questions. Because the group had no formal membership, visitors and relatives came and went, and the line between member and guest was never clear.

The group's record of achievement is remarkable for a circle with no funds and no rules. Priestley isolated a gas he called dephlogisticated air in 1774, a discovery that others would later interpret as oxygen. Wedgwood devised a pyrometer for measuring high temperatures in his kilns, work that earned him election to the Royal Society in 1783. Watt's improvements to the steam engine transformed manufacturing. Withering's Account of the Foxglove, published in 1785, described the use of digitalis in treating dropsy, and Darwin's long poems and medical treatises carried the group's ideas to a wide readership.

Politically and religiously, the members were not typical of the English establishment. Several were Dissenters, Protestants who did not belong to the Church of England and who were therefore barred from the universities and from public office. Most welcomed the early stages of the French Revolution, seeing it as a blow against tyranny. In July 1791 a group of them held a dinner in Birmingham to mark the second anniversary of the fall of the Bastille, and a crowd gathered outside, threw stones and forced the diners to leave.

Worse followed. Over the next few days rioters attacked the houses of prominent Dissenters and burned Priestley's meeting house and his home at Fair Hill, destroying his laboratory, his manuscripts and much of his apparatus. Priestley escaped to London and later emigrated to the United States, where he died in 1804. The riots are usually taken as the end of the society, although the members had already begun to meet less often, and no formal decision to disband was ever taken.

What the group meant has been debated ever since. It left almost no records of its own, so historians have had to reconstruct its activities from letters, diaries and the published work of its members. Some have portrayed it as a coherent organisation with a shared programme; others insist that it was a friendship network whose members disagreed on much. Few historians doubt that its influence on the industrial and scientific life of the Midlands was considerable.

Its wider fame owes much to The Lunar Men, a group biography by Jenny Uglow published in 2002, which presented the circle to a large popular readership. Two of its members, Erasmus Darwin and Josiah Wedgwood, were the grandfathers of Charles Darwin, whose theory of evolution would have astonished them and, one suspects, delighted them.

For several centuries, one of the most widespread industrial structures in the British countryside was the lime kiln: a squat block of stone or brick, often built into a hillside, with a dark opening at its base. Its purpose was to turn limestone or chalk into quicklime through the application of intense heat. The underlying chemistry is straightforward. Limestone and chalk consist largely of calcium carbonate, and when this mineral is heated to about 900 degrees Celsius, carbon dioxide is driven off, leaving calcium oxide, the substance known as quicklime. The stone that emerged was lighter, more brittle and chemically far more reactive than the rock that had been fed in at the top.

Because the raw material is heavy and cheap, kilns were built as close to the quarry as possible, and in southern England, where chalk lies close to the surface, they were extremely numerous. Many were cut into a slope so that carts could tip stone directly into the top of the chamber while the finished lime was removed at a lower level. The earliest kilns burnt wood, brushwood or gorse, and the supply of fuel, rather than the supply of stone, usually determined where a kiln could operate.

Two broad designs dominated. The first is the intermittent, or flare, kiln. A single charge of limestone, layered with fuel, was set alight and left until the fire had burnt through; the kiln was then allowed to cool and emptied before being loaded again. Such kilns were cheap to build and forgiving of poor fuel, but they consumed a great deal of heat, since the chamber had to be warmed and cooled with every batch. The result was a slow cycle of loading, firing and emptying that suited small works.

The second design, the draw kiln, allowed continuous working. A permanent stone-lined shaft was filled with alternate layers of limestone and fuel, and as the lowest lime was raked out through a draw hole at the base, fresh material was added at the top so that the burning zone stayed at a constant level. Draw kilns used fuel more economically and produced a more uniform product, but they demanded greater skill from the burner, who had to judge the draught and the rate of drawing.

Where stone was plentiful and capital scarce, a third and cruder method was used. A clamp kiln was built in the open, without a permanent structure, from rough blocks of limestone stacked with layers of coal or wood and covered with turves or clay. It was fired once and then abandoned, leaving a ring of burnt earth and discarded lime. Dozens of such temporary clamps might be worked on a single estate, and the lime they produced was often of poor and uneven quality.

Fuel changed decisively in the later eighteenth century. Wood had always been expensive and, in much of lowland England, already scarce. Coal was heavier but cheaper per unit of heat, and once canals had made it cheap to move, coal-fired kilns spread quickly along the coalfields and waterways. Coal burnt hotter than wood, but its ash and sulphur could contaminate the lime, and burners learned to keep fuel from direct contact with stone where a pure white product was required.

The lime that came from the kiln was dangerous to handle. When quicklime is treated with water it reacts violently, swelling, cracking and releasing a great deal of heat; a process known as slaking. Added in careful quantities, the water produces a powder, slaked lime; added in excess, it yields a thick paste. Lime putty, matured in pits for weeks or months, was the basis of the mortar used in brick and stone walls, and limewash mixed with water and tallow served as a cheap protective coating for the inside and outside of buildings.

Lime was also used on the land, a practice that spread rapidly in the late eighteenth century. Most British soils are naturally acid, and applying lime raises the pH, releasing nutrients that would otherwise remain locked up; farmers found that liming improved the yield of clover, wheat and turnips. Lime was spread in heaps in the field and left to air-slake, or was mixed with soil before being ploughed in. On estates with their own kilns, the lime was carted out in large quantities each year, and the practice formed one of the more visible links between industry and agricultural improvement.

The trade was dangerous. Burners worked around an open fire and a mass of freshly burnt lime, and burns were common, particularly when rain fell on material that had not yet cooled. Quicklime dust inflamed the eyes and lungs, and the chronic cough of the trade was widely noted. Kilns built into hillsides sometimes collapsed, and the atmosphere inside the chamber, rich in carbon dioxide, could suffocate a worker who entered too soon.

The great age of kiln building in Britain was the late eighteenth and early nineteenth centuries. Enclosure, the spreading practice of liming, the construction of brick houses and the canal network all increased demand at once, and thousands of kilns were erected along the limestone belts. From the 1820s, however, Portland cement began to replace lime mortar in important structures, and cheap imported fertilisers and, later, artificial substitutes reduced farmers' dependence on the old kilns. Many fell into ruin; others were absorbed into large works that burnt lime on an industrial scale.

School science is usually presented as a body of settled knowledge. Pupils learn the law of conservation of energy, the structure of the cell and the mechanism of natural selection, but they are seldom told who established these ideas, when, or against what resistance. In several countries there are now calls to give the history of science a larger place in the curriculum, and the suggestion has an obvious appeal. My own view is that the case is a good one, but that most of the arguments made for it are weaker than they appear, and the strongest argument is rarely heard at all.

The commonest argument is motivational. Stories of discovery, it is said, make abstract ideas memorable and show pupils that science is done by people rather than by textbooks. There is something in this: a lesson on the structure of the atom is more interesting if pupils know that the model was disputed for decades. But the same could be said of any subject, and entertainment is a fragile foundation for a curriculum. Anecdote is easy to include and easy to forget.

A second argument is that history reveals science as a human activity. The thinker most often invoked here is Thomas Kuhn, whose Structure of Scientific Revolutions, published in 1962, described scientific change not as the steady accumulation of truths but as a succession of periods in which one framework, or paradigm, is replaced by another. Kuhn's account has been borrowed enthusiastically by educators, often in a simplified form. It is worth noticing that he was writing about how scientific communities work, not about how to teach fourteen-year-olds, and that his book has been criticised as well as admired.

A third argument concerns method. Curricula often claim that studying the history of science teaches pupils how science works, yet there is no single method to teach. Karl Popper argued that what distinguishes a scientific claim is that it can be tested and could, in principle, be shown to be false, a criterion that philosophers have found useful and also too simple. Historians who have examined what scientists actually did have found few who proceeded as the textbooks describe. Taught honestly, the history will show that discovery has often depended on intuition, rivalry, money and luck.

Against all this stands the strongest practical objection: time. Every hour given to Priestley or Darwin is an hour not given to the periodic table, and the curriculum is already crowded. There is a second objection, less often stated. Because the history of science is a scholarly discipline in its own right, it has its own standards and its own characteristic errors. The most notorious is the habit that Herbert Butterfield attacked in 1931 as the whig interpretation of history: the tendency to arrange the past as a procession towards the present. It praises those who anticipated modern views and dismisses the rest as obstacles.

A well-taught history avoids that error, and in doing so offers something that no amount of practical work can supply: it shows pupils that scientific knowledge is made by communities, within institutions, and under the pressure of events. Robert Merton's study of seventeenth-century England, published in the 1930s, argued that the values of Puritanism — discipline, usefulness, the study of God's creation — encouraged experimental science. The thesis has been argued over ever since, which is precisely why it is worth putting in front of pupils.

The history also changes who counts as a scientist. Mary Somerville, a largely self-taught mathematician and writer, published On the Connexion of the Physical Sciences in 1834, a survey that drew astronomy, physics, chemistry and geology into a single account and was read across Europe. In a review of it the same year, William Whewell coined the word 'scientist', which did not come into general use for decades. Somerville was made an honorary member of the Royal Astronomical Society in 1835, yet women were excluded from the Royal Society until the twentieth century. That is not a decorative fact; it is part of the explanation of what science became.

None of this is a reason to hand the subject over to specialists. The discipline of the history of science is itself relatively young: George Sarton, a Belgian-born scholar who settled in the United States, founded the journal Isis in 1912 and spent much of his life compiling an Introduction to the History of Science, believing that the subject could bridge the sciences and the humanities. That ambition is attractive, but it also means that the history of science is not a store of agreeable stories to be raided by science teachers. It is a field with its own arguments.

What, then, should schools do? I would not create a separate subject, still less an examination in the history of science, for the pupils who most need it are precisely those who are least likely to choose it. I would instead build short, carefully chosen case studies into ordinary science lessons, concentrating on episodes whose outcome was genuinely in doubt at the time, and I would ask historians to help design them. The aim is not to decorate science with anecdotes but to show how knowledge is made. Taught that way, the history earns its place.