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top 10 words in brain distribution (in article): species light bird water fish produce insect female bottle body |
top 10 words in brain distribution (in article): time beam common type state allow company production term sell |
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top 10 words in brain distribution (not in article): egg drink lamp wine beer ant bee nest shark fossil |
top 10 words in brain distribution (not in article): light drink lamp species wine water beer produce bottle plant |
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times more probable under cat 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under key (words not in the model) | |
| The cat'" ("Felis catus"), also known as the domestic cat'" or "'house cat'" to distinguish it from other felines and felids, is a small predatory carnivorous species of crepuscular mammal that is valued by humans for its companionship and its ability to hunt vermin, snakes, scorpions, and other unwanted household pests. It has been associated with humans for at least 9,500 years. A skilled predator, the cat is known to hunt over 1,000 species for food. It can be trained to obey simple commands. Individual cats have also been known to learn on their own to manipulate simple mechanisms, such as doorknobs. Cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Cats may be the most popular pet in the world, with over 600 million in homes all over the world. They are also bred and shown as registered pedigree pets. This hobby is known as the "cat fancy." Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal. However a 2007 study found that the lines of descent of all house cats probably run through as few as five self-domesticating African Wildcats "(Felis silvestris lybica)" circa 8000 BC, in the Near East. Size. Cats typically weigh between 2.5 and 7 kg (5.5–16 pounds); however, some, such as the Maine Coon, can exceed. Some have been known to reach up to due to overfeeding. Conversely, very small cats (less than) have been reported. The largest cat ever was officially reported to have weighed in at about (46 lb 15.25 oz). The smallest cat ever officially recorded weighed around 3 lbs (1.36 kg). Cats average about in height and in head body length (males being larger than females), with tails averaging in length. Skeleton. Cats have 7 cervical vertebrae like almost all mammals, 13 thoracic vertebrae (humans have 12), 7 lumbar vertebrae (humans have 5), 3 sacral vertebrae like most mammals (humans have 5 because of their bipedal posture), and, except for Manx cats, 22 or 23 caudal vertebrae (humans have 3 to 5, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared with humans. The caudal vertebrae form the tail, used by the cat as a counterbalance to the body during quick movements. Cats also have free-floating clavicle bones, which allows them to pass their body through any space into which they can fit their heads. Mouth. Cats have highly specialized teeth for the killing of prey and the tearing of meat. The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently functions to shear meat like a pair of scissors. While this is present in canids, it is highly developed in felines. The cat's tongue has sharp spines, or papillae, useful for retaining and ripping flesh from a carcass. These papillae are small backward-facing hooks that contain keratin which also assist in their grooming. As facilitated by their oral structure, cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. Ears. Thirty-two individual muscles in each ear allow for a manner of directional hearing: a cat can move each ear independently of the other. Because of this mobility, a cat can move its body in one direction and point its ears in another direction. Most cats have straight ears pointing upward. Unlike dogs, flap-eared breeds are extremely rare (Scottish Folds are one such exceptional mutation.) When angry or frightened, a cat will lay back its ears, to accompany the growling or hissing sounds it makes. Cats also turn their ears back when they are playing, or to listen to a sound coming from behind them. The angle of cats' ears is an important clue to their mood. Legs. Cats, like dogs, are digitigrades. They walk directly on their toes, with the bones of their feet making up the lower part of the visible leg. Cats are capable of walking very precisely, because like all felines they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain. Claws. Like nearly all members of family Felidae, cats have protractable claws. In their normal, relaxed position the claws are sheathed with the skin and fur around the toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hind feet. Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces (bedspreads, thick rugs, etc.). It is also possible to make a cooperative cat extend its claws by carefully pressing both the top and bottom of the paw. The curved claws may become entangled in carpet or thick fabric, which may cause injury if the cat is unable to free itself. Most cats have five claws on their front paws, and four or five on their rear paws. Because of an ancient mutation, however, domestic and feral cats are prone to polydactylyism, (particularly in the east coast of Canada and north east coast of the United States) and may have six or seven toes. The fifth front claw (the dewclaw) is proximal to the other claws. More proximally, there is a protrusion which appears to be a sixth "finger". This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of big cats and dogs. It has no function in normal walking, but is thought to be an anti-skidding device used while jumping. Skin. Cats possess rather loose skin; this allows them to turn and confront a predator or another cat in a fight, even when it has a grip on them. This is also an advantage for veterinary purposes, as it simplifies injections. In fact, the lives of cats with kidney failure can sometimes be extended for years by the regular injection of large volumes of fluid subcutaneously, which serves as an alternative to dialysis. The particularly loose skin at the back of the neck is known as the "scruff", and is the area by which a mother cat grips her kittens to carry them. As a result, cats tend to become quiet and passive when gripped there. This behavior also extends into adulthood, when a male will grab the female by the scruff to immobilize her while he mounts, and to prevent her from running away as the mating process takes place. This technique can be useful when attempting to treat or move an uncooperative cat. However, since an adult cat is heavier than a kitten, a pet cat should never be carried by the scruff, but should instead have its weight supported at the rump and hind legs, and at the chest and front paws. Often (much like a small child) a cat will lie with its head and front paws over a person's shoulder, and its back legs and rump supported under the person's arm. Senses. Cat senses are attuned for hunting. Cats have highly advanced hearing, eyesight, taste, and touch receptors, making the cat extremely sensitive among mammals. Cats' night vision is superior to humans although their vision in daylight is inferior. Cat eyes have a tapetum lucidum and cat eyes that are blue typically lack melanin and hence can show the red-eye effect (see odd-eyed cat). Humans and cats have a similar range of hearing on the low end of the scale, but cats can hear much higher-pitched sounds, up to 64 kHz, which is 1.6 octaves above the range of a human, and even one octave above the range of a dog. A domestic cat's sense of smell is about fourteen times as strong as a human's. Due to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness may have been lost by the cat family. To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face. Metabolism. Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term "cat nap" refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon – someone who nods off for a few minutes is said to be "taking a cat nap". Due to their crepuscular nature, cats are often known to enter a period of increased activity and playfulness during the evening and early morning, dubbed the "evening crazies", "night crazies", "elevenses", or "mad half-hour" by some. The temperament of a cat can vary depending on the breed and socialization. Cats with oriental body types tend to be thinner and more active, while cats that have a cobby body type tend to be heavier and less active. The normal body temperature of a cat is between 38 and 39 °C (101 and 102.2 °F). A cat is considered febrile (hyperthermic) if it has a temperature of 39.5 °C (103 °F) or greater, or hypothermic if less than 37.5 °C (100 °F). For comparison, humans have a normal temperature of approximately 36.8 °C (98.6 °F). A domestic cat's normal heart rate ranges from 140 to 220 beats per minute, and is largely dependent on how excited the cat is. For a cat at rest, the average heart rate usually is between 150 and 180 bpm, about twice that of a human (average 80 bpm). Genetics. A 2007 study published in the journal "Science" asserts that all house cats are descended from a group of self-domesticating desert wildcats "Felis silvestris lybica" circa 10,000 years ago, in the Near East. The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes, in which over 200 heritable genetic defects have been identified, many homologous to human inborn errors. Specific metabolic defects have been identified underlying many of these feline diseases. There are several genes responsible for the hair color identified. The combination of them gives different phenotypes. Features like hair length, lack of tail, or presence of a very short tail (bobtail cat) are also determined by single alleles and modified by polygenes. The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, focuses on the development of the cat as an animal model for human hereditary disease, infectious disease, genome evolution, comparative research initiatives within the family Felidae, and forensic potential. All felines, including the big cats, have a genetic anomaly that may prevent them from tasting sweetness, which is a likely factor for their indifference to or avoidance of fruits, berries, and other sugary foods. Feeding and diet. Cats feed on small prey such as insects, birds, and rodents. Feral cats, or house cats who are free-fed, consume about 8 to 16 small meals in a single day. Despite this, adult cats can adapt to being fed once a day. Cats are classified as obligate carnivores, because their physiology is geared toward efficient processing of meat, and lacks efficient processes for digesting plant matter. The cat cannot produce its own taurine (an essential organic acid), and, as it is contained in flesh, the cat must eat flesh to survive (see Taurine and cats). Similarly as with its teeth, a cat's digestive tract has become specialized over time to suit meat eating, having shortened in length only to those segments of intestine best able to break down proteins and fats from animal flesh. This trait severely limits the cat's ability to properly digest, metabolize, and absorb plant-derived nutrients, as well as certain fatty acids. For example, taurine is scarce in plants but abundant in meats. It is a key amino sulfonic acid for eye health in cats. Taurine deficiency can cause a condition called macular degeneration wherein the cat's retina slowly degenerates, eventually causing irreversible blindness. Despite the cat's meat-oriented physiology, it is still quite common for a cat to supplement its carnivorous diet with small amounts of grass, leaves, shrubs, houseplants, or other plant matter. One theory suggests this behavior helps cats regurgitate if their digestion is upset; another is that it introduces fiber or trace minerals into the diet. In this context, caution is recommended for cat owners because some houseplants are harmful to cats. For example, the leaves of the Easter Lily can cause permanent and life-threatening kidney damage to cats, and Philodendron are also poisonous to cats. The Cat Fanciers' Association has a full list of plants harmful to cats. There are several vegetarian or vegan commercially available cat foods supplemented with chemically synthesized taurine and other added nutrients that attempt to address nutritional shortfalls. Cats can be selective eaters (which may be due in some way to the aforementioned mutation which caused their species to lose sugar-tasting ability). However, cats generally cannot tolerate lack of food for more than 36 hours without risking liver damage. Cats have a fondness for catnip, which is sensed by their olfactory systems. Many enjoy consuming catnip, and most will often roll in it, paw at it, and occasionally chew on it. Cats also can also develop odd eating habits. Some cats like to eat or chew on other things like plastic, paper, string, wool, or even coal. This condition is called pica and can threaten the cat's health depending on the amount and toxicity of the non-food items eaten. The condition's name comes from the Latin word for magpie, a bird which is reputed to eat almost anything. Toxic sensitivity. The liver of a cat is less effective at detoxification than those of other animals, including humans and dogs; therefore exposure to many common substances considered safe for households may be dangerous to them. In general, the cat's environment should be examined for the presence of such toxins and the problem corrected or alleviated as much as possible; in addition, where sudden or prolonged serious illness without obvious cause is observed, the possibility of toxicity must be considered, and the veterinarian informed of any such substances to which the cat may have had access. For instance, the common painkiller paracetamol or acetaminophen, sold under brand names such as Tylenol and Panadol, is extremely toxic to cats; because they naturally lack enzymes needed to digest it, even minute portions of doses safe for humans can be fatal and any suspected ingestion warrants immediate veterinary attention. Even aspirin, which is sometimes used to treat arthritis in cats, is much more toxic to them than to humans and must be administered cautiously. Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidental or by well-meaning owners attempting to counter loss of fur, has sometimes proved fatal. In addition to such obvious dangers as insecticides and weed killers, other common household substances that should be used with caution in areas where cats may be exposed to them include mothballs and other naphthalene products, as well as phenol based products often used for cleaning and disinfecting near cats' feeding areas or litter boxes, such as Pine-Sol, Dettol (Lysol), hexachlorophene, "etc." which, although they are widely used without problem, have been sometimes seen to be fatal. Ethylene glycol, often used as an automotive antifreeze, is particularly appealing to cats, and as little as a teaspoonful can be fatal. Essential oils are toxic to cats and there have been reported cases of serious illnesses caused by tea tree oil, and tea tree oil-based flea treatments and shampoos. Many human foods are somewhat toxic to cats; theobromine in chocolate can cause theobromine poisoning, for instance, although few cats will eat chocolate. Toxicity in cats ingesting relatively large amounts of onions or garlic has also been reported. Even such seemingly safe items as cat food packaged in pull tab tin cans have been statistically linked to hyperthyroidism; although the connection is far from proven, suspicion has fallen on the use of bisphenol A-based plastics, another phenol based product as discussed above, to seal such cans. Many houseplants are at least somewhat toxic to many species, cats included and the consumption of such plants by cats is to be avoided. Sociability. For cats, life in close proximity with humans (and other animals kept by humans) amounts to a "symbiotic social adaptation" which has developed over thousands of years. It has been suggested that, ethologically, the human keeper of a cat functions as a sort of surrogate for the cat's mother, and that adult domestic cats live their lives in a kind of extended kittenhood, a form of behavioral neoteny. Cats may express affection towards their human companions, especially if they imprint on them at a very young age and are treated with consistent affection. Regardless of the average sociability of any given cat or of cats in general, there are still any number of cats who meet | A key'" is a device which is used to open a lock. A typical key consist of two parts: the "blade", which slides into the keyway of the lock and distinguishes between different keys, and the "bow", which is left protruding so that torque can be applied by the user. The blade is usually designed to open one specific lock, although master keys are designed to open sets of similar locks. Keys provide an inexpensive, though imperfect, method of authentication for access to properties like buildings and vehicles. As such, keys are an essential feature of modern living in the developed world, aing adorned by key fobs and known as a keychain. House keys. A house key'" is the most common sort of key. There are two main forms. The older form is for lever locks, where a pack of flat levers (typically between two and five) are raised to different heights by the key whereupon the slots or "'gates'" of the levers line up and permit a bolt to move back and forth, opening or closing the lock. The teeth or "'bittings'" of the key have flat tops rather than being pointed. Lever lock keys tend to be bigger and less convenient for carrying, although lever locks tend to be more secure. These are still common in, for example, many European countries. The more recent form is that for a pin tumbler cylinder lock. When held upright as if to open a door, a series of grooves on either side of the key (the key's "'profile'") limits the type of lock cylinder the key can slide into. As the key slides into the lock, a series of pointed teeth and notches allow pins to move up and down until those pins are in line with the shear line of the cylinder, allowing that cylinder to rotate freely inside the lock and the lock to open. These predominate in, for example, the United States of America. Car key. A "'car key'" or an "'automobile key'" is a key used to open and or start an automobile, often identified with the logo of the car company at the head. Modern key designs are usually symmetrical, and some use grooves on both sides, rather than a cut edge, to actuate the lock. It has multiple uses for the automobile with which it was sold. A car key can open the doors, as well as start the ignition, open the glove compartment and also open the trunk (boot) of the car. Some cars come with an additional key known as a "'valet key'" that starts the ignition and opens the drivers side door but prevents the valet from gaining access to valuables that are located in the trunk or the glove box. Some valet keys, particularly those to high-performance vehicles, go so far as to restrict the engine's power output to prevent joyriding. Recently, features such as coded immobilizers have been implemented in newer vehicles. More sophisticated systems make ignition dependent on electronic devices, rather than the mechanical keyswitch. Ignition switches locks are combined with security locking of the steering column (in many modern vehicles) or the gear lever (Saab Automobile). In the latter, the switch is between the seats, preventing damage to the driver's knee in the event of a collision. Keyless entry systems, which utilize either a door-mounted keypad or a remote control in place of a car key, are becoming a standard feature on many new cars. Some of them are handsfree. Some keys are high-tech in order to prevent the theft of a car. Mercedes-Benz uses a key that, rather than have a cut metal piece to start the car, uses an encoded infrared beam that communicates with the car's computer. If the codes match, the car can be started. These keys can be expensive to replace, if lost, and can cost up to US$400. Some car manufacturers like Land Rover and Volkswagen use a 'switchblade' key where the key is spring-loaded out of the fob when a button is pressed. This eliminates the need for a separate key fob. This type of key has also been known to be confiscated by airport security officials. Master key. A "'master key'" is intended to open a set of several locks. Usually, there is nothing special about the key itself, but rather the locks into which it will fit. These locks also have keys which are specific to each one (the "'change key'") and cannot open any of the others in the set. Locks which have master keys have a second set of the mechanism used to open them which is identical to all of the others in the set of locks. For example, master keyed pin tumbler locks will have two shear points at each pin position, one for the change key and one for the master key. A far more secure (and more expensive) system has two cylinders in each lock, one for the change key and one for the master key. Larger organizations, with more complex "grandmaster key" systems, may have several masterkey systems where the top level grandmaster key works in all of the locks in the system. A practical attack exists to create a working master key for an entire system given only access to a single master-keyed lock, its associated change key, a supply of appropriate key blanks, and the ability to cut new keys. This is described in Locksmiths may also determine cuts for a replacement master key, when given several different key examples from a given system. Control key. A "'control key'" is a special key used in removable core locking systems. The control key enables a user with very little skill to remove from the cylinder, quickly and easily, a core with a specific combination and replace it with a core with a different combination. In Small Format Interchangeable Cores (SFIC), similar to those developed by Frank Best of the Best Lock Corporation, the key operates a separate shear line, located above the operating key shear line. In Large Format Removable Cores, the key may operate a separate shear line or the key may work like a master key along the operating shear line and also contact a separate locking pin that holds the core in the cylinder. SFIC's are interchangeable from one brand to another, while LFRC's are not. Double-sided key. A "'double-sided key'" is very similar to a house or car key with the exception that it has two sets of teeth, an upper level standard set of teeth and a lower, less defined set of teeth beside it. This makes the double-sided key's profile and its corresponding lock look very similar to a standard key while making the attempt to pick the lock more difficult. As the name implies, this type of key has four sides, making it not only harder to duplicate and the lock harder to pick, but it is also physically more durable. Paracentric key. A "'paracentric key'" is designed to open a paracentric lock. It is distinguishable by the contorted shape of its blade, which protrudes past the centre vertical line of the key barrel. Instead of the wards on the outer face of the lock simply protruding into the shape of the key along the spine, the wards protrude into the shape of the key along the entire width of the key, including along the length of the teeth. Patented by the Yale lock company in 1898, paracentric cylinders are not exceptionally difficult to pick, but require some skill and know-how on the part of the person attempting to pick the lock. Skeleton key=== A "'skeleton key'" (or "'passkey'") is a very simple design of key which usually has a cylindrical shaft (sometimes called a "shank") and a single, minimal flat, rectangular tooth or "bit". Skeleton keys are also usually distinguished by their "bow", or the part one would grasp when inserting the key, which can be either very plain or extremely ornate. A skeleton key is designed to circumvent the wards in warded locks. Warded locks and their keys provide minimal security and only a slight deterrent as any key with a shaft and tooth that has the same or smaller dimensions will open the lock. However, warded keys were designed to only fit a matching lock and the skeleton key would often fit many. Many other objects which can fit into the lock may also be able to open it. Due to its limited usefulness, this type of lock fell out of use after more complicated types became easier to manufacture. In modern usage, the term "skeleton key" is often misapplied to ordinary bit keys and barrel keys, rather than the correct definition: a key, usually with minimal features, which can open all or most of a type of badly designed lock. Bit keys and barrel keys can be newly-minted (and sold by restoration hardware companies) or antiques. They were most popular in the late 1800s, although they continued to be used well into the 20th century and can still be found today in use, albeit in vintage homes and antique furniture. A bit key is distinguished from a barrel key in that a bit key usually has a solid shank, whereas a barrel shafted key can be made either by drilling out the shank from the bit end or by folding metal into a barrel shape when forging the key. Tubular key. A tubular key'" (sometimes referred to as a "barrel key" when describing a vintage or antique model) is one that is designed to open a tubular pin tumbler lock. It has a hollow, cylindrical shaft which is usually much shorter and has a larger diameter than most conventional keys. Antique or vintage-style barrel keys often closely resemble the more traditional "skeleton key" but are a more recent innovation in keymaking. In modern keys of this type, a number of grooves of varying length are built into the outer surface at the end of the shaft. These grooves are parallel to the shaft and allow the pins in the lock to slide to the end of the groove. A small tab on the outer surface of the shaft prevents the pins in the lock from pushing the key out and works with the hollow center to guide the key as it is turned. The modern version of this type of key is harder to duplicate as it is less common and requires a different machine from regular keys. These keys are most often seen in home alarm systems and bicycle locks, in the United States. Zeiss key. A Zeiss key'" (also known as a "'Cruciform key'") is a cross between a house key and a tubular key. It has three sets of teeth at 90 degrees to each other with a flattened fourth side. Though this type of key is easy to duplicate, the extra sets of teeth deter lockpicking attempts. Do Not Duplicate key. A "'Do Not Duplicate key'" (or "'DND key'", for short) is one which has been stamped "do not duplicate" and or "duplication prohibited" or similar by a locksmith or manufacturer as a passive deterrent to prevent a retail key cutting service from duplicating a key without authorization or without contacting the locksmith or manufacturer who originally cut the key. More importantly, this is an access control system for the owner of the key, such as a maintenance person or security guard, to identify keys that should not be freely distributed or used without authorization. Though it is intended to prevent unauthorized key duplication, copying restricted keys remains a common security problem. There is no direct legal implication in the US for someone who copies a key that is stamped "do not duplicate" (unless it is a government owned key), but there are patent restrictions on some key designs (see "restricted keys"). The Associated Locksmiths of America calls DND keys "not effective security", and "deceptive because it provides a false sense of security." United States Code deals with United States Post Office keys, and deals with United States Department of Defense keys. Restricted key. A restricted keyblank'" is a keyway and blank for which a manufacturer has set up a restricted level of sales and distribution. Restricted keys are often protected by patent, which prohibits other manufacturers from making unauthorized productions of the key blank. In many jurisdictions, customers must provide proof of ID before a locksmith will duplicate a key using a restricted blank. These days, many restricted keys have special in-laid features, such as magnets, different types of metal, or even small computer chips to prevent duplication. Keycard. A "'keycard'", while not actually considered a key, is a plastic card which stores a digital signature that is used with electronic access control locks. It is normally a flat, rectangular piece of plastic and may also serve as an ID card. There are several popular type of keycards in use and include the mechanical holecard, bar code, magnetic stripe, smart card (embedded with a read write electronic microchip), and RFID proximity cards. The keycard is used by presenting it to a card reader; swiping or inserting of mag stripe cards, or in the case of RFID cards, merely being brought into close proximity to a sensor. Bar code technology is not a secure form of a key, as the bar code can be copied in a photocopier and often read by the optical reader. Magnetic stripe keycards are becoming increasingly easy to copy, but have the security advantage that one may change the stored key in a magnetic swipe card in case the current key may be compromised. This immediate change of the "key" information can be applied to other media, but this media probably offers the least expensive option, and the most convenient to users and managers of systems that use this media. Example: If you own a car with this system, you can change your keys anytime you want. You can buy new media anywhere a gift card is sold. At least at this point in time, you could buy a gift card for a penny, then use that as the media for the keys to your car. If the system uses digital environmental data samples to create the "key" string, every car can have a set of keys that no one else has. If a card is stolen, or copied without authorization, the card can be remade, and the car security system can be synchronized with the new card, and no longer activationally responsive to the copy of the old card. This approach can empower the system controller (owner individual or centralized administration of a business). Computerized authentication systems, such as key cards, raise privacy concerns, since they enable computer surveillance of each entry. Currently RFID cards and key fobs are becoming more and more popular due to its ease of use. Many modern households have installed digital locks that make use of key cards, in combination with biometric fingerprint and keypad PIN options. The first keycard was the mechanical holecard type patented by Tor Sørnes, a concept he later developed into the magnetic stripe card key. History of locks and keys. Wooden locks and keys were in use as early as 4,000 years ago in Egypt. It is also said that key was invented by Theodore of Samos in the 6th century BC. In the United States, keys have been seen as a symbol of power since colonial times. When William Penn arrived in Delaware 1682, a very elaborate ceremony was carried out where he was given the key to the defense works. Flat metal keys proliferated in the early 20th century, following the introduction of mechanical key duplicators, which allow easy duplication of such keys. Key duplication. "'Key cutting (after cutting, the metalworking term for "shaping by removing material") is the primary method of key duplication: a flat key is fitted into a vise grip in a machine, with a blank attached to a parallel vise grip, and the original key is moved along a guide, while the blank is moved against a wheel, which cuts it. After cutting, the new key is deburred: scrubbed with a metal brush to remove burrs, small pieces of metal remaining on the key, which, were they not removed, would be dangerously sharp and, further, foul locks. Different key cutting machines are more or less automated, using different milling or grinding equipment, and follow the design of early 20th century key duplicators. Key duplication is available in many retail hardware stores and of course as a service of the specialized locksmith, though the correct key blank may not be available. Certain keys are designed to be difficult to copy, for access control, such as Medeco, while others are simply stamped Do Not Duplicate to advise that access control is requested, but in the US, this disclaimer has no legal weight. History of key duplication. A machine permitting rapid duplication of flat metal keys, which contributed to the proliferation of their use during the 20th century, may have been first invented in the United States in 1917 (image to the left): Keys in Heraldry. Keys appear in various symbols and coats of arms, the most well-known being that of the Vatican- derived from the story of Saint Peter, the first Pope, being given the Keys of Heaven. |