Mirror

They also were used as a portal to another world in Lewis Carroll's Through the Looking Glass. The Royal Marines also there own special forces similar to that of the SAS: the SBS (Special Boat Service) or The Boat Troop; and the Mountain Troop. In Tlön, Uqbar, Orbis Tertius, a fictional heresiarch declares that "mirrors and copulation are abominable, since they both multiply the numbers of men.". Navy SEALs and the British Royal Marines now serve a similar function, being a ship-based force specially trained in commando-style operations and tactics. In Dreamtigers, he writes of fearing that his reflection would move independently or change shape before his eyes. However the U.S. Mirrors, along with labyrinths, figure prominently in the work of Argentine writer Jorge Luis Borges, who often used them as symbols of infinity, impersonation, and illusion. Eventually the Marine Corps became a separate arm in the United States, with their own equipment.

Illuminated rotating disco balls covered with small mirrors are used to cast moving spots of light around a dance floor. Much later during the age of sail, a component of marines served a similar role, being ship-borne soldiers who were used either during boarding actions, as sharp-shooters, or in raids along the shore. Mirrors are often used in magic to create an illusion. These were troops primarily trained in land warfare, and did not need to be skilled at handling a ship. The hall of mirrors, commonly found in amusement parks, is an attraction in which a number of distorted mirrors are used to produce unusual reflections of the visitor. During the era of the Roman empire, the naval forces included legionaries for boarding actions. This technique was used by Native American tribes and numerous militaries to transmit information between distant outposts. Flag Officers:.

The signal can be used over long distances, possibly up to 60 kilometres on a clear day. Officers:. With the sun as light source, a mirror can be used to signal, by variations in the orientation of the mirror. Senior Ratings and Warrant Officers. A decorative reflecting sphere of thin metal-coated glass, working as a reducing wide-angle mirror, is sold as a Christmas tree decoration called a bauble. Ratings:. Mirrors, typically large and unframed, are frequently used in interior decoration to create an illusion of space, and amplify the apparent size of a room. For the Royal Navy the ranks are as follows (in acending order):.

Its purpose is to split a beam of light so that half passes straight through, while the other half is reflected — this is useful for interferometry. Flag Officers:. The same type of mirror, when used in an optical instrument, is called a half-silvered mirror or beam splitter. Officers:. It may be used to observe criminal suspects or customers (to watch out for theft). Non-Commissioned Officers:. Persons on the dark side see through it - it looks like a transparent window. Non-Commissioned Members:.

Persons on the brightly lit side see their own reflection - it looks like a normal mirror. For the Canadian Navy the ranks are as follows (in acending order):. It is used between a dark room and a brightly lit room. "Flag officers" include any rank that includes the word "admiral", and are generally in command of a battle group or similar flotilla of vessels, rather than a single vessel or aspect of a vessel. It is a sheet of glass coated with a layer of metal only a few dozen atoms thick, allowing some of the light through the surface (from both sides). Typical ranks for commissioned officers include the following, in ascending order:. A one-way mirror, also called two-way mirror, reflects about half of the light and lets the other half pass. Warrant Officers serve in more technical positions than commissioned Officers.

Use of a large number of mirrors in a confined space can act to satisfy people's desire for satisfication of their ego, as in the hall of mirrors in the Palace of Versailles. The United States draws its Warrant Officers from the enlisted ranks. Other uses of mirrors in hedonistic acts include the classic 'mirror on the ceiling' for use during sex (see The Eagles' Hotel California), and the use of mirrors for 'cutting' and snorting cocaine. Warrant Officers, (WO) including Chief Warrant Officers (CWO), are senior to enlisted sailors and junior to commissioned Officers. upskirt. Navy, sailors are more commony referred to by their "rating," which indicates both their rank and job specialty (for example, "BT3 Jones" for "Boiler Technician 3rd Class Jones"). A mirror is sometimes used for voyeurism, e.g. Within the U.S.

High quality flat mirrors are essential for making corner reflectors, which are used for emergency location, and even laser ranging to the Moon. Typical enlisted ranks include the following, in ascending order:. Mirrors are also sometimes used as part of security systems, so that a single video camera can show more than one angle at a time. A navy will typically have two sets of ranks, one for enlisted personnel and one for officers. Rounded (convex) mirrors are sometimes placed at road junctions, and corners of places such as parking lots or stores, allowing people to see around corners to avoid crashing into other vehicles or shopping carts. The largest unit size may be the whole Navy or Admiralty. There exist rear view sunglasses, of which the left end of the left glass and the right end of the right glass work as mirrors. Vessels may be combined into squadrons or flotillas, which may be formed into fleets.

Some motorcycle helmets have a built-in so-called MROS (Multiple Reflective Optic System): a set of reflective surfaces inside the helmet which together function as a rear-view mirror [1]. Naval forces are typically arranged into units based on the number of vessels included, a single vessel forming the smallest operational unit. Rear-view mirror are applied in and on vehicles (such as cars, or bicycles), to allow drivers to see other vehicles coming up behind them. This allows strike groups and combat vessels to remain at sea for several months at a time. In astronomy, adaptive optics is a technique to measure variable image distortions and adapt a mirror accordingly on a timescale of milliseconds, to compensate for the distortions. Today, naval strike groups on longer missions are always followed by a range of support and replenishment vessels supplying them with anything from fuel and munitions, to medical treatment and postal services. Such mirrors are often used in lasers. Also, in WWII, the engine room needed about a dozen sailors to work the many engines, however, today, only about 4-5 are needed (depending on the class of the ship).

The best mirrors of this type can reflect >99.999% of the light (in a narrow range of wavelengths) which is incident on the mirror. However, today ships can go on very long journeys without refuling. By careful choice of the type and thickness of the dielectric layers, the range of wavelengths and amount of light reflected from the mirror can be specified. In WWII, ships needed to refuel very often. These are glass (or sometimes other material) substrates on which one or more layers of dielectric material are deposited, to form an optical coating. Also, the efficiency of the engines have improved a lot, in terms of fuel, and of how many sailors it takes to operate them. For scientific optical work, dielectric mirrors are often used. However, today ships can easily reach 25 knots, thanks to much improved propulsion systems.

The reflectivity as a function of wavelength depends on both the thickness of the coating and on how it is applied. The average speed was about 15-20 knots. For instance, aluminum mirrors are commonly coated with magnesium fluoride. On another note, ships of WWII were much slower than today. Mirror surfaces are sometimes given thin film overcoatings both to retard degradation of the surface and to increase their reflectivity in parts of the spectrum where they will be used. For a list of the prefixes used with ship names (HMS, USS, &c.) see ship prefix. A hot mirror is the opposite, the coating preferentially reflects infrared. Naval ship names are typically prefixed by an abbreviation indicating the national navy in which they served.

A cold mirror is made by using a transparent substrate and choosing a coating material that is more reflective to visible light and more transmissive to infrared light. During the age of sail, the vessel categories were divided into the ship of the line, frigate, and sloop-of-war. This is exploited in some optical work to make cold mirrors and hot mirrors. There are also support and auxiliary vessels, including the minesweeper, patrol boat, and tender. The reflectivity of the mirror coating can be measured using a reflectometer and depends on the wavelength of light as well as the metal. The categories are: Aircraft Carriers, Battleships, Cruisers, Destroyers,Frigates, Submarines and Amphibious assault ships. Front silvered mirrors have to be resurfaced occasionally to keep their quality. Modern naval vessels are generally divided into seven main categories.

A protective overcoat is usually applied before the mirror is removed from the vacuum, because the coating otherwise begins to corrode as soon as it is exposed to oxygen and humidity in the air. On occasion, naval vessels have also served as troop carriers or supply ships. The coatings are typically applied by vacuum deposition. Often, other ships which were not built specifically for warfare, such as the galleon or the armed merchant ships in World War II, did carry armaments. They reflect 90% to 95% of the incident light when new. They were designed to withstand damage and to inflict the same, but only carried munitions and supplies for the voyage (rather than merchant cargo). All of these coatings are easily damaged and require special handling. Historically, naval vessels have been specialized ships that were primarily intended for warfare.

Some of them use silver, but most are aluminum, which is more reflective at short wavelengths than silver.
. Telescopes and other precision instruments use front silvered mirrors, where the reflecting surface is placed on the front surface of the glass, which gives better image quality. As the tradition evolved, the number of cannons fired became an indication of the rank of the official being saluted. This may be to check physical appearance (including clothing, make-up, hair, etc.) or to control applying make-up, shaving, cutting hair, fixing one's tie, etc. The British, as the dominant naval power, compelled the ships of weaker nations to make the first salute. A mirror is used for inspecting parts of one's body which are difficult or impossible to see directly, such as the face, neck or the whole body. When a cannon is fired, it partially disarms the ship, so firing a cannon for no combat reason showed respect and trust.

The "back side" of the mirror is often painted black to completely seal the metal from corrosion. rThe custom of firing cannon salutes originated in the British Royal Navy. This type of mirror reflects about 80% of the incident light. Later ceremonies employed the casket or crematory urn. They are back silvered, where the reflecting surface is viewed through the glass sheet; this makes the mirror durable, but lowers the image quality of the mirror due to extraneous reflections from the front surface of the glass. After a solemn ceremony, the board was tilted and the body dropped into the deep. Most modern mirrors consist of a thin layer of aluminium deposited on a sheet of glass. (During the age of sail, the final stitch was placed through the nose of the victim, just to make sure they were really dead.) The body was then placed on a pivoting table attached to the outer hull, and shrouded by a national ensign.

Early mirrors were usually a sheet of polished metal, often silver or copper, for example the Aranmula kannadi. In the past this involved sewing the body up in a shroud that had a weight at one end, often a cannonball. In either case, an observer farther from the mirror than you will see your normal orientation directly and in the mirror before you turn, and will then observe that you put your right hand where your left was if you rotate the usual way, or your head where your feet were if you stand on your head. By ancient tradition, corpses on board naval vessels were buried at sea. If one rotated about a horizontal axis parallel to the mirror surface, one would appear upside down. [3]. The question is sometimes asked, "Why does the mirror reverse left to right and not top to bottom?" The answer is that one has rotated (as is most comfortable) about a vertical axis to face the mirror. Australia, Canada, Spain and Norway have opened submarine service to women sailors, however.

When the rotation is so obvious that it is not worth mentioning, the second component in this decomposition of the effect of the mirror is sometimes emphasized, by saying that a mirror "reverses left and right". [2] The UK Royal Navy has similar restrictions. In particular, if one looks at one's image in a vertical mirror in left-right orientation, the image corresponds to a rotation by 180° about the vertical axis in the mirror, combined with a reflection in one's approximate symmetry plane. Navy are the extended duty tours and close conditions which afford almost no privacy. In this case the image of the person is in normal standing orientation and vertically in a normal position, at a horizontally different position and with an orientation rotated about a vertical axis, the latter except if the mirror is parallel to the approximate symmetry plane of the person. The major reasons cited by the U.S. This is the case iff the mirror is vertical. submarines.

The image is the most realistic if it is still vertical, i.e., if the rotation is about a vertical axis. Even today, despite their acceptance in many areas of naval service, women are still not permitted to serve on board U.S. We can apply this to the image in a mirror of, say, a standing person, because people have approximate bilateral symmetry. In spite of these views, some women did serve on board naval vessels, usually as wives of crewmembers. For an object with approximate reflection symmetry, a reflection in some mirror plane corresponds to a combination of:. The only women that were welcomed on board were figureheads mounted on the prow of the ship. That is, if the beam of light is shining on a mirror's surface at a 30° angle from vertical, then it reflects from the point of incidence at a 30° angle from vertical in the opposite direction. To do so would invite a terrible storm that would wreck the ship.

A beam of light reflects off a mirror at an angle of reflection that is equal to its angle of incidence. However, it was long considered bad luck to permit women to sail on board naval vessels. Note that spherical concave and convex mirrors do not have a single focal point, as often described in high school physics text books (see spherical aberration in lens (optics) and aberration in optical systems). By European tradition, ships have been referred to as a "she". Finally, there are convex mirrors, where a parallel beam becomes divergent, with the apparent intersection occurring behind the mirror. In the United States, in a tradition that dates back to the Revolutionary War, the First Navy Jack is a flag that has the words, "Don't Tread on Me" on the flat. There are also parabolic concave mirrors, where a parallel beam of light becomes a convergent beam, whose rays intersect in the focus of the mirror. it is now used to pipe a senior officer on board the ship - anyone like the captain or more senior.

In a plane mirror, a parallel beam of light changes its direction as a whole, whilst still remaining parallel; the images formed by a plane mirror are virtual images, of the same size as the original object (see mirror image). The two tones it gives of and the number of blasts given off, signify the order given. . The piping is done by the ship's bosun and therefore is Known as the Bosun's Whistle. The most common use is in the home for personal grooming but mirrors are also used in scientific apparatus such as telescopes and lasers, and in industrial machinery. This was original used to give orders on warships when shouted orders could not have been heard. The best known example is the plane mirror. Anouther important tradition is that of Piping someone aboard the ship.

A mirror is a surface with good specular reflection that is smooth enough to form an image. The bell was originally kept polished first by the ship's cook, then later by a person belonging to that division of the ship's personnel. a reflection in the approximate symmetry plane of the object (due to the assumption this is a minor change). They were also employed as warning devices in heavy fog, and for alarms and ceremonies. a translation if the mirror is parallel to the symmetry plane of the object, and otherwise a rotation about the line of intersection of the two planes by an angle which is twice the angle between the two planes. This was historically used to mark the passage of time on board a vessel, including the duration of four-hour watches. and other nations) has been the ship's bell.

An important tradition on board British naval vessels (and later those of the U.S. Blue water fleets may require specialized vessels, such as mine sweepers, when operating in the littoral regions along the coast. Regional powers may maintain a "green water navy" as a means of localized force projection. By contrast a "brown water navy" operates in the coastal periphery and along inland waterways, where larger ocean-going naval vessels can not readily enter.

Many are also nuclear powered to save having to refuel. These are ships capable of maintaining station for long periods of time in deep ocean, and will have a long logistical tail for their support. A "blue water navy" is designed to operate far from the coastal waters of its home nation. Later these were replaced by the radio transmitter, or the flashing light when radio silence was needed.

At night signal lamps could be used for a similar purpose. Prior to the invention of radio, commands from the flag ship were communicated by means of flags. The commander of a fleet travels in the flag ship, which is usually the most powerful vessel in the group. Navy ships normally operate with a group, which may be a small squadron of comparable vessels, or a larger naval fleet of various specialized ships.

Nations with historically strong naval forces have found it advantageous to obtain basing rights in areas of strategic interest. During times of war temporary bases may be constructed in closer proximity to strategic locations, as it is advantageous in terms of patrols and station-keeping. The base is a port that is specialized in naval operations, and often includes housing for off-shore crew, an arsenal depot for munitions, docks for the vessels, and various repair facilities. Historically a national navy operates from one or more bases that are maintained by the country or an ally.

However, a few nations that lacked a navy but were faced with an enemy that was a strong naval power, such as Rome during the Punic wars, built a powerful navy from scratch. Nations that have a significant maritime trade economy have also had an incentive to protect their interests with a potent navy. Historically, naval powers have been those countries that have a long coastline and a strong economy. This gives the ship a tactical edge in warfare.

These ships have a low radar signature and are only detectable at short distances. In recent times modern navies are increasingly investing in stealth ships. The US Navy has indicated it may procure as many as 60 such vessels.[1]. But in recent years, faced with the new requirements, larger navies, notably the US Navy have started developing these capacities as well, by planning and constructing the Littoral Combat Ship.

Traditionally, this has been the main focus of some of the smaller European navies, especially the scandinavian navies, such as the Norwegian Navy and the Swedish Navy. Since the end of the Cold war, and with the disappearance of the Cold war scenario, there has been a return of focus to ships being able to operate in more coastal environments, in support of operations such as amphibious landings, embargo enforcement, peacekeeping and coastal patrol. The main consideration is for Carrier Battle Groups (CVBGs). One scenario that was the focus of American naval planning during the Cold War was a conflict between two modern and well equipped fleets on the high seas, the clash of the United States and the Soviet Union.

In shallow waters, the detection of submarines and mines is especially problematic. The presence of land and the bottom topology of an area compress the battle space, limit the opportunities to maneuver, make it easier for an enemy to predict the location of the fleet and make the detection of enemy forces more difficult. This is why a navy prefers the open sea. There is also the concept of battle space: a zone around a naval force within which a commander is confident of detecting, tracking, engaging and destroying threats before they pose a danger.

Much time and effort is spent to deny the enemy the chance to detect one's forces. In naval warfare, the key is to detect the enemy while avoiding detection. Movement is a large component of modern combat; a naval fleet can travel hundreds of kilometres in a day. The basic idea of all tactics (land, sea and air) is fire and movement: the fulfillment of a mission by the effective delivery of firepower resulting from scouting and the creation of good firing positions.

The presence of land, changing water depths, weather, detection and electronic warfare, the dreadful speed at which actual combat occurs and other factors — especially air power — render naval tactics truly formidable. This is not, however, the truth. This assumes there is no cover, there are no civilians and the area of combat is level and flat. It is tempting to regard modern naval combat as the purest expression of tactics.

Many leading thinkers, however, suggest that navies are more important today than ever and may even surpass armies once again as the main measure of a nation's military might. By the late 20th century, naval power had become a major element in the military and strategic power of a country's power projection capabilities, though some would suggest its importance has declined in the wake of the development of military aviation and air power. By the end of World War II, the carrier had become the dominant force of naval warfare. First at Taranto and then in Pearl Harbor, the aircraft demonstrated its ability to strike decisively at enemy ships out of sight and range of surface vessels.

A major paradigm shift in naval warfare occurred with the introduction of the aircraft carrier. The X-craft severely damaged her and kept her in port for some months. The German battleship Tirpitz, a sister ship of the Bismarck, was almost put out of action by miniature submarines known as X-Craft. During WWII the German Navy's submarine fleet of U-boats almost starved Britain into submission, and inflicted tremendous losses on US coastal shipping.

The first practical military submarines were developed in the late 1800s and by the end of WWI they had proved to be a powerful arm of naval warfare. A further step change in naval firepower occurred when Britain launched HMS Dreadnought, but naval tactics still emphasised the line of battle. The battle between the CSS Virginia and the USS Monitor during the American civil war is often cited as the beginning of this age of maritime conflict. Another significant improvement came with the invention of the rotating turrets, which allowed the guns to be aimed independently of ship movement.

The first armoured vessels, the French FS Gloire and British HMS Warrior, made wooden vessels obsolete. The increased mass required steam-powered engines, which resulted in an arms race between armor thickness and firepower. The next stage in the evolution of naval warfare was the introduction of metal plating along the hull sides. These conflicts saw the development and refinement of tactics which came to be called the line of battle.

From 1695 the Royal Navy began to more successfully assert itself and throughout the eighteenth century gradually gained increasing ascendancy over the French navy, with victories in the Spanish War of Succession (1701-1714), inconclusive battles in the War of Austrian Succession (1740-1748), victories in the Seven Years War (1754-1763), a reversal during the American War of Independence (1775-1783), and consolidation into uncontested supremacy during the nineteenth century from the Battle of Trafalgar in 1805. England emerged as a major naval power in the mid seventeenth century in the first Anglo-Dutch war with a technical victory, but successive decisive Dutch victories in the second and third Anglo-Dutch wars confirmed the Dutch mastery of the seas during the Dutch Golden Age, which was financed largely by building the overseas Dutch empire at the expense of the Portuguese. From the 1620s Dutch raiders began to seriously trouble Spanish shipping and finally the Dutch navy broke the long dominance of the Spanish in the Battle of the Downs (1639). The repulsion of the Spanish Armada (1588) by the Anglo-Dutch fleet revolutionised naval warfare by the success of a guns only strategy, and caused a major overhaul of the Spanish navy, partly along English lines, which resulted in even greater dominance by the Spanish.

The development of large capacity, sail-powered ships carrying cannon led to a rapid expansion of European navies, especially the Spanish and Portuguese navies, which dominated in the sixteenth and early seventeenth centuries, and ultimately helped propel the age of exploration and colonialism. Warships were designed to carry increasing numbers of cannon, and naval tactics evolved bring a ship's firepower to bear in a broadside, with ships-of-the-line arranged in a line of battle. The mass and deck space required to carry a large number of cannon made oar-based propulsion impossible, and ships came to rely primarily on sails. Naval warfare continued in this vein through the Middle Ages until cannon became commonplace and capable of being reloaded quickly enough to be reused in the same battle.

In the time of Ancient Greece and the Roman empire, naval warfare centred around long, narrow vessels powered by banks of oarsmen (such as triremes and quinqueremes) designed to ram and sink enemy vessels, or come alongside the enemy vessel so its occupants could be attacked hand-to-hand. Prior to the introduction of the cannon, and ships with sufficient capacity to carry the large guns, naval warfare primarily involved ramming and boarding actions. Naval warfare first developed whenever humankind conducted fighting from water-borne vessels. .

. This is not the case for every navy, however: some are just for defence such as Japan's navy, part of the JDF (Japanese Defence Force). The strategic task of the navy also may incorporate of nuclear deterance by use of nuclear missiles. The strategic defensive purpose of a Navy is to frustrate sea-borne projection-of-force by enemies.

The strategic offensive role of a Navy is projection-of-force into areas beyond a country's shores (for example, to protect sea-lanes, ferry troops, or attack other navies, ports, or shore installations). It includes operations conducted by surface vessels, and Amphibious (ships), submarine vessels, and seaborne aviation, as well as ancillary support, communications, training, and other fields; recent developments have included space-related operations. A navy (often Navy) is the branch of a country's military forces principally designated for naval warfare and amphibious warfare (marines) namely lake- or ocean-borne combat operations and related functions. Aubrey–Maturin series by Patrick O'Brian.

Forester. S. Hornblower series by C. Tom Clancy, The Hunt for Red October.

Fiction: