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Birch Tar
Birch tar or birch pitch is a substance (liquid when heated) derived from the dry distillation of the bark of the birch tree. Compounds It is composed of phenols such as guaiacol, cresol, xylenol, and creosol. Ancient and modern uses Birch tar was used widely as an adhesive as early as the Middle Paleolithic to early Mesolithic era. Neanderthals produced tar through the dry distillation of birch bark as early as 200,000 years ago. A study from 2019 showed that birch tar production can be a very simple process, merely involving the burning of birch bark near smooth vertical surfaces in open air conditions. A rare find from the Dutch North Sea shows that Neanderthals used birch bark tar as a backing on small 'domestic' stone tools. Birch tar also has been used as a disinfectant, in leather dressing, and in medicine. 5,000-year-old chewing gum made from birch bark tar and still bearing tooth imprints, has been found in Kierikki in Finland. Genetic material retained in the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birch Bark
Birch bark or birchbark is the bark of several Eurasian and North American birch trees of the genus ''Betula''. The strong and water-resistant cardboard-like bark can be easily cut, bent, and sewn, which has made it a valuable building, crafting, and writing material, since pre-historic times. Today, birch bark remains a popular type of wood for various handicrafts and arts. Birch bark also contains substances of medicinal and chemical interest. Some of those products (such as betulin) also have fungicidal properties that help preserve bark artifacts, as well as food preserved in bark containers. Collection and storage Removing birch bark from live trees is harmful to tree health and should be avoided. Instead, it can be removed fairly easily from the trunk or branches of dead wood, by cutting a slit lengthwise through the bark and pulling or prying it away from the wood. The best time for collection is spring or early summer, as the bark is of better quality and most easil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chewing Gum
Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its texture is reminiscent of rubber because of the physical-chemical properties of its polymer, plasticizer, and resin components, which contribute to its elastic-plastic, sticky, chewy characteristics. History The cultural tradition of chewing gum seems to have developed through a convergent evolution process, as traces of this habit have arisen separately in many early civilizations. Each early precursor to chewing gum was derived from natural growths local to the region and was chewed purely out of the instinctual desire to masticate. Early chewers did not necessarily desire to derive nutritional benefits from their chewable substances but at times sought taste stimuli and teeth cleaning or breath-freshening capabilities. Chewing gum in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The BMJ
''The BMJ'' is a weekly peer-reviewed medical trade journal, published by the trade union the British Medical Association (BMA). ''The BMJ'' has editorial freedom from the BMA. It is one of the world's oldest general medical journals. Originally called the ''British Medical Journal'', the title was officially shortened to ''BMJ'' in 1988, and then changed to ''The BMJ'' in 2014. The journal is published by BMJ Publishing Group Ltd, a subsidiary of the British Medical Association (BMA). The editor-in-chief of ''The BMJ'' is Kamran Abbasi, who was appointed in January 2022. History The journal began publishing on 3 October 1840 as the ''Provincial Medical and Surgical Journal'' and quickly attracted the attention of physicians around the world through its publication of high-impact original research articles and unique case reports. The ''BMJ''s first editors were P. Hennis Green, lecturer on the diseases of children at the Hunterian School of Medicine, who also was its fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vishnevsky Liniment
Vishnevsky liniment or balsamic liniment (, ) is a topical medication which has been used to treat wounds, burns, skin ulcers and suppurations. Developed by Russian surgeon Alexander Vishnevsky in 1927, the liniment contains birch tar, xeroformium (bismuth tribromophenolate) and castor oil which have been broadly used as a topical medication in the former Soviet Union. Vishnevsky liniment was broadly used in the Soviet army during World War II. It was later shown that a prolonged application of Vishnevsky liniment for chronic skin ulcers, wounds or burns can be associated with higher risk of skin cancer, hematologic Hematology ( always spelled haematology in British English) is the branch of medicine concerned with the study of the cause, prognosis, treatment, and prevention of diseases related to blood. It involves treating diseases that affect the produc ... or other malignancy. References Ointments Abandoned drugs Soviet inventions Drugs in the Soviet Union ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Export Good
A trade route is a logistical network identified as a series of pathways and stoppages used for the commercial transport of cargo. The term can also be used to refer to trade over bodies of water. Allowing goods to reach distant markets, a single trade route contains long-distance arteries, which may further be connected to smaller networks of commercial and noncommercial transportation routes. Among notable trade routes was the Amber Road, which served as a dependable network for long-distance trade. Maritime trade along the Spice Route became prominent during the Middle Ages, when nations resorted to military means for control of this influential route. During the Middle Ages, organizations such as the Hanseatic League, aimed at protecting interests of the merchants and trade became increasingly prominent. In modern times, commercial activity shifted from the major trade routes of the Old World to newer routes between modern nation-states. This activity was sometimes carried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oiling (leather Processing)
Oiling is a process whereby leather is hand coated (usually by brush or tampon) with either a raw (un-emulsified) oil or a combination of raw oil, blended with emulsified oils and a penetrating aid. Hand oils can include fragrant oils that help with the smell associated with the leather, e.g., Pine Oil. Hand oils commonly consist of sulfated vegetable oils, e.g. sulfated castor oil. Oiling provides the leather with lubrication and allows it to flex repeatedly without cracking. Leather fibres that are dry and un-lubricated break very easily. Oiling does impart colour and an element of water resistance. Oiling would normally be performed on full grain aniline leathers. The most common type of leather oiled is vegetable tanned leather. See also * Currying * Russia leather Russia leather is a particular form of bark-tanned cow leather. It is distinguished from other types of leather by a processing step that takes place after tanning, where birch oil is worked into the rear face of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russia Leather
Russia leather is a particular form of bark-tanned cow leather. It is distinguished from other types of leather by a processing step that takes place after tanning, where birch oil is worked into the rear face of the leather. This produces a leather that is hard-wearing, flexible and resistant to water. The oil impregnation also deters insect damage. This leather was a major export good from Russia in the 17th and 18th centuries because of its high quality, its usefulness for a range of purposes, and the difficulty of replicating its manufacture elsewhere. It was an important item of trade for the Muscovy Company. In German-speaking countries, this leather was also known by the name Juchten or Juften. Production Producing the leather involved three processes: * Tanning the leather. This was a bark tanning process, similar to other vegetable-tanned leather. * Saturating the tanned hide with birch oil. This is the most distinctive part of the process, giving Russia leather its water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rawhide (textile)
Rawhide is a hide or animal skin that has not been exposed to tanning. It is similar to parchment, much lighter in color than leather made by traditional vegetable tanning. Rawhide is more susceptible to water than leather, and it quickly softens and stretches if left wet unless well waterproofed. "Rawhide" laces often sold for boots or baseball gloves are made of normal tanned leather rather than actual rawhide. Rawhide is not pliable when dry and would be unsuitable for that use. Process The skin from buffalo, deer, elk or cattle from which most rawhide originates is prepared by removing all fur, meat and fat. The hide is then usually stretched over a frame before being dried. The resulting material is hard and translucent. It can be shaped by rewetting and forming before being allowed to thoroughly re-dry. It can be rendered more pliable by 'working', i.e. bending repeatedly in multiple directions, often by rubbing it over a post, sometimes traditionally by chewing. It may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers called fletchings mounted near the rear, and a slot at the rear end called a nock for engaging the bowstring. A container or bag carrying additional arrows for convenient reloading is called a quiver. The use of bows and arrows by humans predates recorded history and is common to most cultures. A craftsman who makes arrows is a fletcher, and one that makes arrowheads is an arrowsmith.Paterson ''Encyclopaedia of Archery'' p. 56 History The oldest evidence of likely arrowheads, dating to c. 64,000 years ago, were found in Sibudu Cave, current South Africa.Backwell L, d'Errico F, Wadley L.(2008). Middle Stone Age bone tools from the Howiesons Poort layers, Sibudu Cave, South Africa. Journal of Archaeological Science, 35:1566–1580. Backwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fletching
Fletching is the fin-shaped aerodynamic stabilization device attached on arrows, bolts, darts, or javelins, and are typically made from light semi-flexible materials such as feathers or bark. Each piece of such fin is a fletch, also known as a flight or feather. A fletcher is a person who attaches fletchings to the shaft of arrows. The word is related to the French word , meaning 'arrow', via the ultimate root of Old Frankish . Description As a noun, ''fletching'' refers collectively to the fins or vanes, each of which individually is known as a fletch. Traditionally, the fletching consists of three matched half-feathers attached near the back of the arrow or shaft of the dart that are equally spaced around its circumference. Four fletchings have also been used. In English archery, the male feather, from a cock, is used on the outside of the arrow, while the other two stabilizing feathers are from a female, or hen. Traditional archery lore about feather curvature is that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hunter-gatherer
A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, honey, or anything safe to eat, and/or by hunting game (pursuing and/or trapping and killing wild animals, including catching fish), roughly as most animal omnivores do. Hunter-gatherer societies stand in contrast to the more sedentary agricultural societies, which rely mainly on cultivating crops and raising domesticated animals for food production, although the boundaries between the two ways of living are not completely distinct. Hunting and gathering was humanity's original and most enduring successful competitive adaptation in the natural world, occupying at least 90 percent of human history. Following the invention of agriculture, hunter-gatherers who did not change were displaced or conquered by farming or pastoralist groups in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
