True / False / Not Given

Public libraries in many cities have changed substantially over the last twenty years. Once defined mainly by printed books and quiet reading rooms, they now offer services such as language classes, job-search workshops, digital media labs, and public internet access. This shift has been partly driven by changes in how people find information, but it has also reflected a wider understanding of libraries as civic spaces where residents can learn skills and meet others.

The move toward digital services has not meant that printed collections are disappearing. In a 2022 survey of urban library systems, most libraries reported stable or slightly rising borrowing figures for children's books, even while adult fiction loans declined. Library managers explained that families often use picture books and early readers alongside online resources, rather than replacing one format with another. Several systems have also expanded their print collections in languages commonly spoken by local immigrant communities.

Funding remains a serious constraint. Although library visits increased in many neighbourhoods after extended opening hours were introduced, the additional staffing costs made the policy difficult to maintain. Some branches reduced specialist workshops during budget reviews, while others relied on volunteers to support basic computer sessions. Researchers warn that volunteer-led services can be valuable, but they cannot fully substitute for trained staff when visitors need detailed help with legal forms, employment applications, or accessibility technology.

Another challenge is measuring success. Traditional indicators, such as the number of books borrowed, capture only part of a modern library's role. A teenager who uses a library computer to submit a college application may not borrow a book, but the visit may still have significant educational value. For this reason, several city councils have begun collecting broader data, including programme attendance, Wi-Fi use, study-room bookings, and community feedback.

Despite these changes, librarians argue that the central purpose of the institution has remained consistent: providing free access to knowledge. What has changed is the form that access takes. A library may now lend tablets, teach coding, host health-information sessions, or provide a warm public space during winter, but these activities are extensions of the same public mission rather than departures from it.

Natural rubber, harvested from the sap of certain tropical trees, was known in Europe by the eighteenth century, but its practical uses were severely limited. In its raw state the material was highly sensitive to temperature: it turned soft and sticky in summer heat and became hard and brittle in winter cold. Waterproof boots and coats made from it were briefly fashionable in the 1820s, yet customers quickly abandoned them once the garments melted in warm weather or cracked in the frost. By the early 1830s, many investors had come to regard rubber as a commercial dead end.

Charles Goodyear, an American hardware merchant with no formal training in chemistry, became convinced that rubber could be stabilised if it were treated correctly. From 1834 onwards he devoted himself almost entirely to the problem, often working in borrowed kitchens and even in prison cells, where he was confined for unpaid debts. He experimented by mixing raw rubber with a wide range of substances — magnesia, lime, nitric acid — achieving partial and unreliable improvements. His family endured years of poverty as he pursued the research, and contemporaries frequently dismissed him as a hopeless dreamer.

The breakthrough came in 1839, and according to the best-known account it was partly accidental. Goodyear was handling a mixture of rubber and sulfur when a portion of it came into contact with a hot stove. Instead of simply melting, the rubber charred slightly but retained its elasticity, and the material around the scorched area stayed firm and flexible even after it had cooled. Goodyear grasped the significance of what he had seen and spent several further years working out the precise combination of heat, time, and sulfur needed to make the process reliable.

Goodyear obtained a United States patent for the process, later named vulcanisation, in 1844. Commercial success, however, continued to elude him. His patents were widely infringed, and the legal battles he fought to defend them consumed much of what little money he earned. In England, the manufacturer Thomas Hancock examined samples of Goodyear's rubber, developed a comparable process of his own, and secured a British patent a few weeks before Goodyear's own application there. Goodyear died in 1860 owing substantial debts, having never profited significantly from an invention that others were already exploiting.

Vulcanised rubber went on to transform nineteenth- and twentieth-century industry. Its durability and resistance to temperature made possible products ranging from industrial seals and hoses to the pneumatic tyres on which modern road and air transport depend. The Goodyear Tire and Rubber Company, founded several decades after his death, took its name in his honour, although it had no direct connection to the inventor or his family.

The idea that sleep plays an active part in memory has a long history, but only in recent decades have researchers begun to map the mechanisms involved. Memory formation is now commonly described as a two-stage process. During waking experience, new information is encoded in a fragile, temporary form. For this information to be retained, it must subsequently be consolidated — stabilised and integrated into long-term storage. A growing body of evidence indicates that much of this consolidation occurs during sleep, rather than during the waking hours that follow learning.

Sleep is not a uniform state. It cycles through distinct phases, the most studied of which are slow-wave sleep, characterised by large, synchronised brain waves, and rapid-eye-movement (REM) sleep, during which most vivid dreaming occurs. Experiments in which volunteers learn lists of words or pairs of facts suggest that slow-wave sleep is particularly important for declarative memory — the conscious recollection of facts and events. Participants allowed a period of slow-wave sleep after learning typically recall more than those kept awake for an equivalent period, even when the total elapsed time is held constant.

The role of REM sleep is more contested. Some studies associate it with the consolidation of procedural memory — the largely unconscious 'how-to' knowledge involved in skills such as typing or playing an instrument. Other researchers question whether REM sleep is essential at all, pointing out that certain medications suppress REM almost entirely without producing the dramatic memory deficits the theory might predict. The relationship between specific sleep phases and specific kinds of memory therefore remains an area of active disagreement.

Studies of sleep deprivation reinforce the link between sleep and memory, though they must be interpreted with care. People deprived of sleep after learning generally perform worse on later tests than those allowed to sleep. However, sleep loss also impairs attention and mood, so a poor test result may partly reflect a failure to concentrate rather than a failure to consolidate. Disentangling these effects is methodologically difficult, and researchers increasingly favour study designs that monitor brain activity directly rather than relying solely on behavioural measures.

Despite considerable progress, fundamental questions remain open. It is not yet clear why consolidation should depend on sleep at all, when in principle it might occur during periods of quiet wakefulness. Nor is there agreement on whether the memory functions of sleep evolved as its primary purpose or merely as a secondary benefit of a state that serves other needs. What most researchers now accept, however, is that sleep is far from the passive shutdown it was once assumed to be.