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Salt Water Dimmer
Salt water dimmers, which are an early example of liquid rheostats, were used in theatres after the introduction of electric stage lighting to control the brightness of the lights on stage. Electric lighting Electric lighting replaced gas lights in theatres from the 1880s. The first theatre to replace the gas lighting totally with electric lighting was the Savoy Theatre in 1881. Salt water dimmers A dimmer consisted of a glass jar filled with salt water with a metal electrode at each end. As the upper electrode was moved away from the lower electrode, the resistance increased and the lights got dimmer. The brightness also depended on the concentration of salt in the water. The switchboard built at Her Majesty's Theatre, London in 1897 had a dimmer scale of 0 to 10, whereas gas lighting only had 3 levels. The salt water need to be refilled regularly, the metal electrodes corroded, and the dimmers emitted a strong smell. The dimmers were hazardous both because of the flammabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Water Dimmers At Alexandra Palace Theatre
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as rock salt or halite. Salt is essential for life in general (being the source of the essential dietary minerals sodium and chlorine), and saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, and is known to uniformly improve the taste perception of food. Salting, brining, and pickling are ancient and important methods of food preservation. Some of the earliest evidence of salt processing dates to around 6000 BC, when people living in the area of present-day Romania boiled spring water to extract salts; a salt works in China dates to approximately the same period. Salt was prized by the ancient Hebrews, Greeks, Romans, Byzantines, Hittites, Egyptians, and Indians. Salt became an impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Rheostat
A liquid rheostat or water rheostat or salt water rheostat is a type of variable resistor. This may be used as a dummy load or as a starting resistor for large slip ring motors. In the simplest form it consists of a tank containing brine or other electrolyte solution, in which electrodes are submerged to create an electrical load. The electrodes may be raised or lowered into the liquid to respectively increase or decrease the electrical resistance of the load. To stabilize the load, the mixture must not be allowed to boil. Modern designs use stainless steel electrodes, and sodium carbonate, or other salts, and do not use the container as one electrode. In some designs the electrodes are fixed and the liquid is raised and lowered by an external cylinder or pump. Motor start systems used for frequent and rapid starts and re-starts, thus a high heat load to the rheostats, may include water circulation to external heat exchangers. In such cases anti-freeze and anti-corrosion addi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stage Lighting
Stage lighting is the craft of lighting as it applies to the production of theater, dance, opera, and other performance arts. Stage Lighting Design Principle and Process Several different types of stage lighting instruments are used in this discipline. theatrecrafts' Types of Lanterns. In addition to basic lighting, modern stage lighting can also include special effects, such as Laser lighting display, lasers and fog machines. People who work on stage lighting are commonly referred to as lighting technicians or lighting designers. The equipment used for stage lighting (e.g. cabling, Salt water dimmer, dimmers, lighting instruments, contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Light
''Gas Light'' is a 1938 thriller play, set in 1880s London, written by the British novelist and playwright Patrick Hamilton. Hamilton's play is a dark tale of a marriage based on deceit and trickery, and a husband committed to driving his wife insane in order to steal from her. ''Gas Light'' was written during a dark period in Hamilton's life. Six years prior to the play Hamilton was hit by a drunk driver and dragged through the streets of London, leaving him with a limp, a paralysed arm, and a disfigured face. Two years later, Hamilton's mother took her own life. Premiering at the Richmond Theatre in London on 5 December 1938 before transferring to the Apollo Theatre in the West End on 1 January, the play closed after six months and 141 performances, but it has endured through an impressive list of incarnations most notably ''Five Chelsea Lane'' (1941 American playrenamed for Los Angeles production), ''Angel Street'' (1941 American playrenamed again when Los Angeles pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Savoy Theatre
The Savoy Theatre is a West End theatre in the Strand in the City of Westminster, London, England. The theatre was designed by C. J. Phipps for Richard D'Oyly Carte and opened on 10 October 1881 on a site previously occupied by the Savoy Palace. Its intended purpose was to showcase the popular series of comic operas of Gilbert and Sullivan, which became known as the Savoy operas. The theatre was the first public building in the world to be lit entirely by electricity. For many years, the Savoy Theatre was the home of the D'Oyly Carte Opera Company, which continued to be run by the Carte family for over a century. Richard's son Rupert D'Oyly Carte rebuilt and modernised the theatre in 1929, and it was rebuilt again in 1993 following a fire. It is a Grade II* listed building. In addition to '' The Mikado'' and other famous Gilbert and Sullivan premières, the theatre has hosted such premières as the first public performance in England of Oscar Wilde's '' Salome'' (1931) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Water
Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, but less salty than brine. The salt concentration is usually expressed in parts per thousand (permille, ‰) and parts per million (ppm). The USGS salinity scale defines three levels of saline water. The salt concentration in slightly saline water is 1,000 to 3,000 ppm (0.1–0.3%); in moderately saline water is 3,000 to 10,000 ppm (0.3–1%); and in highly saline water is 10,000 to 35,000 ppm (1–3.5%). Seawater has a salinity of roughly 35,000 ppm, equivalent to 35 grams of salt per one liter (or kilogram) of water. The saturation level is only nominally dependent on the temperature of the water. At one liter of water can dissolve about 357 grams of salt, a concentration of 26.3 percent by weight (% w/w). At (the boiling temperat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
His Majesty's Theatre, London
His Majesty's Theatre is a West End theatre situated in the Haymarket, London, Haymarket in the City of Westminster, London. The building, designed by Charles J. Phipps, was constructed in 1897 for the actor-manager Herbert Beerbohm Tree, who established the Royal Academy of Dramatic Art (RADA) at the theatre. In the early decades of the 20th century Tree produced spectacular productions of William Shakespeare, Shakespeare and other classical works, and the theatre hosted premieres by such playwrights as George Bernard Shaw, Bernard Shaw, J. M. Synge and, later, Noël Coward and J. B. Priestley. Since the First World War the wide stage has made the theatre suitable for large-scale musical productions, and His Majesty's has accordingly specialised in hosting musical theatre, musicals. It has been home to record-setting musical theatre runs such as the First World War hit ''Chu Chin Chow'' and Andrew Lloyd Webber's ''The Phantom of the Opera (1986 musical), The Phantom of the Oper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Dimmer
A dimmer is a device connected to a light fixture and used to lower the brightness of the Lighting, light. By changing the voltage waveform applied to the lamp, it is possible to lower the Luminous intensity, intensity of the light output. Although variable-voltage devices are used for various purposes, the term ''dimmer'' is generally reserved for those intended to lighting control system, control light output from resistive Incandescent light, incandescent, Halogen lamp, halogen, and (more recently) compact fluorescent lamps (CFLs) and light-emitting diodes (LED lamp, LEDs). More specialized equipment is needed to dim Fluorescent lamp, fluorescent, Mercury-vapor lamp, mercury-vapor, Solid-state lighting, solid-state, and other Arc lamp, arc lighting. Dimmers range in size from small units the size of domestic light switches to high-power units used in large theatrical or architectural lighting design, architectural lighting installations. Small domestic dimmers are generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
