IELTS Academic Reading Practice Test 297

In the north-west of New Mexico, a shallow canyon cuts through a high, dry plateau. Its walls are of sandstone, and along the floor runs a wash that carries water only after summer storms. Between about 850 and 1150, the ancestors of today's Pueblo peoples built here a group of monumental structures that archaeologists call great houses. Spanish-speaking settlers later gave the place the name by which it is now known, Chaco Canyon. For centuries they remained the largest buildings in North America north of Mexico.

The greatest of these structures is Pueblo Bonito, a vast D-shaped complex that grew by stages. Construction began in the middle of the ninth century and continued, with long interruptions, for some two hundred years. In its final form the building rose to four storeys at the rear and contained several hundred rooms; estimates vary, and some archaeologists count around 650. Thirty or more circular rooms, known as kivas, were sunk into the ground or built into the plaza. The rooms themselves were small, cool and dark, and most were probably used for storage rather than for living.

The masonry is striking even to visitors who know nothing of the period. Builders faced their walls with thin tablets of sandstone, split and shaped with stone tools and laid in regular courses with a mortar of mud. Behind this neat outer skin they packed a core of rubble and smaller stones. This technique, which archaeologists call core-and-veneer masonry, produced walls that were both strong and relatively light, and some of them still stand to their original height after nine centuries of frost, sun and occasional earth tremors.

Timber was the greater problem. The canyon has few large trees, yet its buildings required many thousands of beams to support roofs and floors. For a long time it was assumed that the wood had been collected nearby. Tree-ring dating changed that picture, and analysis of the chemical signature of the wood has changed it further. Most of the beams, it now appears, were carried from mountain ranges sixty kilometres away or more, especially the Chuskas to the west, where ponderosa pine grows tall and straight. How the logs were moved remains uncertain; they may have been dragged, rolled or passed from hand to hand along human chains.

Chaco is also famous for the straightness of its roads. Lines of cleared ground run out from the canyon across the desert, some of them for sixty kilometres, ignoring the easy curves of the land. They are best seen from the air, and their purpose is debated: they may have been processional routes, or markers of a shared way of seeing the world, or simply practical paths. The great houses themselves are aligned with the cardinal directions, and on a butte overlooking the canyon three slabs of rock cast a blade of sunlight across a spiral carving at the solstices.

Farming in such a place required ingenuity. The canyon receives barely twenty centimetres of rain in a year, and the wash is unpredictable. Farmers built low dams and check dams across small channels to slow the water and spread it over their fields, and laid out grids of stones to trap soil and hold moisture. Maize, beans and squash were grown, but the harvest can never have been secure. Years of drought occur often enough in the region's tree-ring record for researchers to trace them in the timbers of the buildings themselves.

Objects found in the rooms hint at connections that reached far beyond the canyon. Cylindrical jars, a shape otherwise rare in the region, were found to contain the residue of chocolate, the drink made from cacao, which cannot grow within a thousand kilometres of Chaco. Skeletons of scarlet macaws, brilliant birds of the Mexican tropics, were buried in several rooms. Turquoise from distant sources was worked into ornaments in enormous quantities. Such goods suggest that Chaco was not an isolated village but a place to which people, and precious materials, travelled.

Modern study of the canyon began in the 1890s, when a museum-sponsored expedition dug into Pueblo Bonito, and continued in the 1920s with a much larger project financed by a geographical society. Those excavations removed a great deal of material and left records that are still consulted, although by present standards their methods were rough. Later archaeologists have worked more carefully, and much current research re-examines objects and samples held in museum stores, applying techniques that the first excavators could not have imagined.

Why the building stopped is a question with several answers. Tree-ring dating shows that construction had largely ceased by the 1130s. A series of dry decades followed, and the removal of timber from the surrounding hills may have worsened the effects of drought. There is evidence of violence and of sudden burning at some outlying settlements. By about 1200 the canyon was largely empty, and its people had moved south and east, where their descendants live today among the Pueblo nations.

Chaco is now protected as a national park. In 1907 it was declared a national monument, in 1980 it became a national historical park, and in 1987 it was added to the World Heritage List. For many Pueblo people the canyon is a sacred landscape rather than a ruin, and the excavation and display of ancestral human remains has caused deep and continuing disagreement. Visitors are asked to treat the place with restraint, which is perhaps the least that its builders deserve.

Before there were instruments, there were words. For as long as people have kept written records, they have noted the weather: whether the harvest would be good, whether a ship could sail, whether the roads were passable. Weather mattered to nearly everyone: to the farmer deciding when to sow, the merchant waiting for a cargo, the clerk burying a neighbour after a hard winter. Chronicles, diaries, letters, parish registers, ships' logs and farmers' almanacs are full of such remarks, and in the last few decades historians and climate scientists have begun to read them systematically. The result is a growing body of evidence about the climate of the past, and a lively argument about how far that evidence can be trusted.

The earliest sources are chronicles and annals, kept in monasteries and at royal courts, which record unusual weather alongside battles and the deaths of kings. Their weakness is obvious: an author notes the winter that froze the river, not the ordinary winter that did not. Such sources are therefore records of extremes rather than of averages, and the further back they go, the thinner they become. Diaries are richer. From the sixteenth century onwards, educated men and women in Europe increasingly noted each day's wind, rain and temperature, sometimes with care and sometimes from memory at the end of a week. These entries were rarely intended for anyone else, which is both their charm and their difficulty.

The most abundant written records, however, come from the sea. From the middle of the nineteenth century, naval and merchant vessels were required to keep official logbooks, in which officers entered the wind direction, the state of the sea and the weather several times a day. Many thousands of these volumes survive in national archives. Since the 2000s, volunteers working online have transcribed millions of entries from digitised images, producing a dataset that no single research team could have afforded to compile. The logs have their own bias, since ships avoided storms where they could and whole oceans were rarely visited, but they cover periods and places for which little else exists.

Instruments arrived gradually. The thermometer and the barometer were developed during the seventeenth century, and by the eighteenth observers in several countries were making regular readings. The decisive step came in 1780, when a learned society based in Mannheim, in what is now Germany, organised a network of observing stations across Europe and beyond. It distributed identical instruments, issued detailed instructions and asked observers to record at fixed hours. For more than a decade the network produced a remarkably consistent set of observations, and its example shaped the national weather services that followed. Regular observation was expensive and fragile: instruments broke, observers died, and wars interrupted the post.

Even instrument readings, however, need interpreting. Early thermometers used different scales and were mounted in different ways: one might hang on a north wall, another beside a stove. Observers read them at whatever hour suited them, and a conscientious observer's records may be less useful than a careless one's, because the conscientious observer moved house and carried the instrument along. Even the hour of observation matters, since the warmest part of the day falls in the afternoon. Stations close, open and shift by a few hundred metres. To build a series that means anything over a century, researchers must adjust for all these changes, and every adjustment is a judgement that someone else may dispute.

Where documents are silent, other evidence fills the gap. The date on which grapes were picked in Burgundy has been recorded for centuries, and because the fruit ripens earlier in a warm year, those dates can be read as a rough thermometer. Wine growers have kept such lists since the Middle Ages, and historians have used them to reconstruct summer temperatures going back many centuries. The freezing of lakes has been noted in Japan and in northern Europe, and the flooding of the Nile was recorded by scribes for thousands of years. Such proxy records are not measurements, but when several of them point in the same direction they are difficult to ignore.

The debates are as much about method as about data. One group of scholars uses statistical techniques to convert diaries and chronicles into estimates of temperature and rainfall, treating each descriptive remark as a data point. Others argue that this turns rich, human documents into numbers their authors never intended, and that a phrase such as 'a great frost' cannot be given a value on any scale. Both sides agree that the sources are unevenly distributed: towns wrote more than villages, and literate societies more than others. The argument is not merely academic, since reconstructions of past climate are used to test the computer models that forecast the future.

There is also disagreement about what the records mean. The idea of a 'Little Ice Age', a cold period of several centuries, is widely used but loosely defined, and some historians contend that it was mainly a European phenomenon rather than a global one. Documentary evidence is strongest for Europe, where the scribes were, so there is a risk of confusing where records were kept with where the weather was cold. Nor is it clear how far a run of severe winters in one region tells us about the climate of a hemisphere. Climate historians have learned to be cautious, but the work continues, one marginal note at a time.

Walk into almost any museum of history or art and you will find the same scene: objects in cases, and small rectangles of print beside them. In recent years a number of curators have begun to reduce that print, or to remove it altogether, on the grounds that objects can tell their own stories. I have sympathy with the impulse. There is something liberating about being left alone with a thing, and something oppressive about being told, in three lines of authoritative prose, exactly what to feel. But the idea that an object speaks for itself seems to me a romantic illusion, and a costly one. The gallery of unlabelled objects is a fashion, and fashions pass.

The label is a nineteenth-century invention. The great museums of that era were arranged as surveys of the world, in which each object was assigned a place in a hierarchy of peoples and periods. Labels told visitors what that place was, and their tone was frequently confident to the point of arrogance. Labels also carried the authority of the institution: a printed card stating that an object was 'Roman, second century' settled the matter. It is hardly surprising that later generations of curators, suspicious of that authority, tried to do without it. The bare white gallery, with objects isolated and text reduced to a name and a date, was a reaction against the crowded Victorian case.

The case for fewer words rests on attention. Reading and looking compete for the same narrow resource, and a visitor who is reading is not, for that moment, seeing. Labels that describe what is plainly visible — 'a blue glazed bowl' — waste the visitor's time. Worse, a label can close down an object. Say that a mask was used in a particular ceremony and the visitor is likely to see nothing else; leave it unexplained and the mask may suggest a dozen possibilities. Curators who work with objects from cultures other than their own have a further reason for caution, since every explanatory sentence risks imposing an interpretation that the makers of the object would not have recognised.

Yet the case is weaker than it appears. An object does not speak; a visitor interprets, using knowledge already possessed. To a specialist, a Benin bronze is dense with meaning, because the specialist knows the kingdom, the casting method, the court ritual and the history of how the piece left Africa. To most visitors it is a handsome metal head. The difference between the two responses is not sensitivity but information. Museums exist precisely because such information is not innate. Removing the label does not make the object more democratic; it flatters those who already know and quietly excludes those who do not.

Museums have known this for decades. Studies of visitor behaviour, carried out by institutions themselves since at least the 1960s, have generally found that people read few labels and spend only a short time at each object. This is sometimes offered as proof that labels are useless. It proves nothing of the kind. It shows that labels are badly written. Text set in small type at knee height, in long unbroken paragraphs, will not be read; a short line at eye level, phrased as a question, often will be. Visitors are not, in any case, a single audience.

Then there is the question of whose story is being told. A label is never neutral. The phrase 'gift of a colonial officer' can conceal a great deal, and until recently few museums asked what the giver had been doing when the object came into his hands. Campaigns for the return of looted material have made these silences visible. Some institutions have responded by rewriting their labels to say openly what is known, and what is not, about how objects were acquired. That seems to me entirely right. The answer to dishonest labels is not no labels; it is honest ones. Silence, in a museum, is rarely neutral either.

Digital interpretation is often presented as the solution. A visitor can now point a phone at a case and summon as much or as little text as they wish, in any of several languages. Where it is well done, this is a genuine advance: information becomes layered, and the visitor chooses how deep to go. But the phone introduces difficulties of its own. It competes for attention more fiercely than any label, it assumes equipment that not everyone owns or wishes to use, and it allows a museum to avoid the harder task of deciding what matters most. An audio guide has similar drawbacks, with the added disadvantage of a voice in the ear that competes with the object itself. A label that everyone can read remains the most democratic device available.

So what should a label do? It should give the facts the object cannot give: what it is made of, who made it, when, and how it reached the museum. It should be modest in length and in tone, and where the evidence is uncertain it should say so. It should acknowledge that other readings are possible. Above all it should ask something of the visitor, if only a question. Wonder and understanding are not enemies, but they are not the same thing either, and a museum that offers only the first has not finished its job. The best labels I have read feel less like verdicts than like conversation.