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Mara SalvatruchaFrom Wikipedia, the free encyclopedia  (Redirected from MS-13)• Interested in contributing to Wikipedia? •Mara SalvatruchaYears active 1980 - presentTerritory mostly Central America, United States, EuropeEthnicity HispanicMembership 100,000+Criminal activities Drug trafficking, robbery, extortion, gun trafficking, murder, contract killing, etc.Mara Salvatrucha refers to large gangs in Central America and the United States. The gang names are commonly abbreviated as MS[1], Mara, and MS-13, and are composed mostly of Salvadorans, Guatemalans, Hondurans, and other Central Americans. The Mara Salvatrucha gangs have cliques, or factions, located throughout the United States and Latin America.

The gang has moved beyond its Salvadoran and American origins and now can be found in other nations, including Canada, Mexico, Guatemala, Colombia, Spain, Great Britain and Germany, according to international press on criminal activity. Membership in the U.S was believed to be as many as 10,000 in the United States as of 2005.[2] MS-13 criminal activities include drug smuggling and sales, black market gun sales, human trafficking, theft, assaults on law enforcement officials, and contract killing.[3]

Their activities have caught the eye of the FBI, who in September 2005 initiated wide-scale raids against suspected gang members, netting 660 arrests across the country.[4] In the United States, the gang's strongholds have historically been in Pennsylvania, New York, New Jersey, Miami, Southern California, Washington, D.C., Northern Virginia, Maryland, the Hampton Roads area of Virginia, Richmond, and Delaware. In Allentown, Harrisburg, Philadelphia, and other areas of Pennsylvania, the gang is known for its street graffiti, which is used to depict their presence on certain blocks and also sometimes provides clues to their forthcoming crimes, including murder, robbery, narcotics, and especially as a prediction of retaliatory violence.Former gang member Brenda Paz said that MS is well structured, with multiple leaders, and that the gang's goal is to become the top gang in the United States.[4]

[edit]History

The Mara Salvatrucha gang originated in Los Angeles.[5] There is some dispute about the etymology of the name (see below: Etymology). The most common belief is that the word "Mara" refers to the Spanish word for "gang", and it is suggested that "Salvatrucha" refers to the Salvadoran guerrillas, the source of much of the gang's early manpower. The gang was set up in Los Angeles in 1980's by Salvadoran immigrants in the city's Pico-Union neighborhood.[6]

Originally, the gang's main purpose was to protect Salvadoran immigrants from other, more established gangs of Los Angeles, who were predominately comprised of Mexicans and Mexican-Americans. For this reason, the gang initially allowed only Salvadorans to join, but later allowed others to join as well. The Current Leader is suspected to be Luis "Jorge" Gomez.[citation needed].

Many Mara Salvatrucha gang members from the Los Angeles area have been deported either because of their illegal status in the United States, or for committing crimes as non-citizens, or both. As a result of these deportations, members of MS-13 have recruited more members in their home countries. The Los Angeles Times contends that deportation policies have contributed to the size and influence of the gang both in the United States and in Central America. El Salvadoran authorities report that approximately 60% of prison inmates serving time for gang-related crimes there have either fled prosecution or been deported from the United States.[7]

[edit]Publicized crimes
On July 23, 2003, Brenda Paz, a 17-year old female, was found murdered on the banks of the Shenandoah River in Virginia. Brenda Paz was killed for "snitching" or telling the police about Mara Salvatrucha activities. Four of her friends were later convicted of the murder.[8]

On December 23, 2004, one of the most widely publicized MS-13 crimes in Central America happened in Chamelecón, Honduras. An intercity bus was intercepted and sprayed with automatic gunfire, killing 28 passengers most of whom were women and children. [9] Those convicted were MS-13 gang leaders and in February 2007 the courts found Juan Carlos Miranda Bueso and Darwin Alexis Ramírez guilty of several crimes including murder and attempted murder. Ebert Anibal Rivera was held over the attack and was arrested in Texas after having fled [10]. Juan Bautista Jimenez, accused of masterminding the attack, was killed in prison. According to the authorities, he was hanged by fellow MS-13 inmates.

On May 13, 2006, Ernesto "Smokey" Miranda was murdered at his home in El Salvador, a few hours after declining to attend a party for a gang member who had just been released from prison. He had begun studying law and working to keep children out of gangs. He was an ex-high ranking soldier and one of the founders of the Mara Salvatrucha.[11]

[edit]Illegal immigration and human smugglingAccording to The Washington Times, MS-13 "is thought to have established a major smuggling center" in Mexico.[12] There were reports that MS-13 members were ordered to Arizona to target border guards and Minuteman 
Project volunteers.[13][14].In 2005, Honduran Security Minister Oscar Alvarez and the President of El Salvador raised alarm by claiming that Al-Qaeda was meeting with MS-13 and other Central American gangs to help them infiltrate the United States. FBI agent Robert Clifford said that the U.S. intelligence community and governments of several Central American countries found there is no basis to believe that MS-13 is connected to Al-Qaeda or other Islamic radicals although he did visit Central America to discuss the issue.[15]

Robert Morales, a prosecutor for Guatemala, indicated to The Globe and Mail that some Central American gang members seek refugee status in Canada. Superintendent of the Royal Canadian Mounted Police integrated gang task force, John Robin, said in an interview that "I think [gang members] have a feeling that police here won't treat them in the harsh manner they get down there".[16] Robin noted that Canadian authorities "want to avoid ending up like the U.S., which is dealing with the problem of Central American gangsters on a much bigger scale".[16]

[edit]Etymology
There are various possible explanations for the name Mara Salvatrucha. Some sources state the gang is named for La Mara, a street in San Salvador, and the Salvatrucha guerrillas who fought in El Salvador's bloody civil war [17]. Additionally, the word mara means gang in Caliche and is taken from marabunta, the name of a fierce type of ant. "Salvatrucha" is a portmanteau of Salvadoran and trucha, a Caliche word for being alert, usually entailing preparedness for crime or abuse from police.

[edit]Gang markings and hand signs
An MS-13 suspect bearing gang tattoos is handcuffed. In 2004, the FBI created the MS-13 National Gang Task Force. A year later, the FBI helped create National Gang Intelligence Center.

Many Mara Salvatrucha members cover themselves in tattoos. Common markings include "MS", "Salvatrucha" the "Devil Horns" the name of their clique and other symbols.[18] A December 2007 CNN internet news article stated that the gang was moving away from the tattoos in an attempt to commit crimes without being noticed. [19]Members of MS-13, like members of most modern American gangs, utilize a system of hand signs for purposes of identification and communication. One of the most commonly displayed is the "devil's head" (formed by extending the index and little fingers of the hand while tucking in the middle and ring fingers with the thumb), which forms an M when displayed upside down. This hand sign is similar to the same symbol commonly seen displayed by heavy metal musicians and their fans. It is alleged that the founders of Mara Salvatrucha borrowed the hand sign after attending heavy metal concerts.[citation needed]

[edit]See also
List of California street gangsMara 18[edit]References
^ "The Fight Against MS-13." _CBC News_. 04-12-2005. 60 Minutes. Accessed 14-11-2007. p.1 Note: See before last paragraph. The expression "MS" appears within this article as a term used by Brenda Paz. She says "...the three places MS will lead you – jail, hospital or the cemetery,..." and makes reference to the gang MS-13. This reference may be a violation of WP:SYNT.^ del Barco, Mandalit (2005-03-17). "The International Reach of the Mara Salvatrucha". NPR News. Retrieved 2006-11-15.^ "Marijuana - Virginia Drug Threat Assessment". Drug Intelligence Center (March 2002).^ a b Rather, Dan (2005-12-04)."The Fight Against MS-13". CBS News. Retrieved 2006-11-16.^ The International Reach of the Mara Salvatrucha : NPR^ The International Reach of the Mara Salvatrucha : NPR^ Lopez, Robert J.; Rich Connell and Chris Kraul. "Gang Uses Deportation to its Advantage to Flourish in the U.S.", Los Angeles Times, October 30, 2005. Retrieved on 2007-12-05. ^ Bradley, Paul (2005-04-10). "[1]".Potomac News Online. Retrieved 2007-03-05.^ BBC NEWS | Americas | Gang linked to Honduras massacre^ BBC NEWS | Americas | Honduras massacre 'leader' held^ del Barco, Mandalit (2006-05-16). "Gang Leader Shot to Death on Road to Reform". NPR News. Retrieved 2006-11-15.^ http://www.washtimes.com/national/20040928-123346-3928r
.htm^ http://www.washtimes.com/national/20050328-125306-7868r
.htm^ Report: MS-13 gang hired to murder Border Patrol - DailyBulletin.com^ Danna Harman (2/23/2005). U.S. steps up battle against Salvadoran gang MS-13. USA Today. Retrieved on 2007-11-13. “"The FBI, in concert with the U.S. intelligence community and governments of several Central American republics, have determined that there is no basis in fact to support this allegation of al-Qaeda or even radical Islamic ties to MS-13 (Mara Salvatrucha)," says Robert Clifford, director of the new task force.”^ a b Mason, Gary (2008-01-07). Canada is a haven to gangsters on the run. The Globe and Mail. Retrieved on 2008-01-07.^ http://www.apfn.org/APFN/MS-13.HTM^ Werner, Zach (2005-10-05). "FBI Targets MS-13 Street Gang". NewsHour Extra. Retrieved 2006-12-11.^ "[2]"[edit]External links
MS-13 Current News and Analysis"18 with a Bullet" Wide Angle PBS"How the Street Gangs Took Central America" May/June 2005 Foreign Affairs"For Salvadoran gangs, jail is a revolving door" March 1, 2005 The Christian Science Monitor"Gangs, Terrorists, and Trade" April 12, 2007 in Foreign Policy In Focus"World's Most Dangerous Gang", National Geographic Television production on Google Video[3] National Geographic post-investigation essay.Spotlight on MS-13 gang, New York Times, 19 August 2007Categories: Los Angeles area street gangs | Gangs in Massachusetts | Terrorism in the United States | Hispanic gangs | 1971 establishments | Organized crime groups in Latin America | Mara Salvatrucha | Modern street gangsarticle discussion edit this page history

This page was last modified on 16 May 2008, at 20:47. All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.Privacy policy About Wikipedia DisclaimersWikipedia is sustained by people like you. Please donate today.

Any difference in 21st century use of the Periodic Table of Elements?  At least I'm listening to Shell right now.  Very educational and transparent.   Shell Oil Company: my advice:  Get a global discussion about an InterLinear Qur'an: Arabic2Hebrew to divert attention;)

I'm reduced to this in order to accomplish my lifestyle.  Since the K-9 Corps,  Animal Control, the animal section of NIH and NIMH, and PETA won't help:
Is there any way I can keep my dog in my car so he can breathe while I'm shopping?  I want my dog to live my life.  I want my dog's brain to evolve.  Why do certain individuals have federal support to raise monkeys and I can't raise my Baruch the way I want to at my own taxable expense?  It's a matter of simple knowledge and innovation.  Why can't I use my car as a day care for my dog?
My Garland, TX veterinarian who visited my home told me I shouldn't keep my Galileo, bicnon frise/westie  fenced in my front room because it was too empty and I should get a cardboard box and keep it there so he can have a den.
There's got to be a way to keep a dog in a car.  As it is, think about it.  Stores are usually open until 10 p.m.   So I could go shopping with Baruch in moonlight.   It's cooler then.  The problem with keeping him alone at night is he might start barking and that's a no-no.  There is no excuse for causing a huge debate for something that the K-9 Corps, Animal Control, PETA and NIMH can get together on.  Dogs aren't even monkies.  Hey, maybe they evolved like human beings from monkies;)   Who KNOWS?   Well, I don't know about you but I have conersations with YHWH/oo.ah.ee.ah;)
How come the rich and famous always have dogs with them wherever they go.  Even the kings of ancient Europe.  I think it's outrageous that the media shows rich and famous Ho's with dogs everywhere.  How about Bros and Sweeties.

Innovate in the USA.  Encourage Doggie Day Camps in Shopping Centers so we can walk and shop in our Communities.  Communitize Capitalism.

Capitalism has a real problem.  It's a problem of knowledge.  When an employee knows a lot, that employee can capitalistically sell himself. 

 The University of Texas understood all this.  So they used the vocabulary of the Quality Circle and circumvented it by using carefully selected "multiple choice" to control the outcomes and established individual monitors all over the USA to ensure that outcome.  I  now realize that I had to live in Texas to find that out.  It took me over 20 years and lots of luck, I mean really dumb luck for this poor old bitch.  It started with a female in Dallas in Reston, VA. in my Managerial Grid Quality Circle and a fine senior citizen male at Dallas's Temple Emanu-El.  If it weren't for the V.I.P.'s of M.C.I. it never would have happened for me.  

Quality circleFrom Wikipedia, the free encyclopedia• Learn more about using Wikipedia for research •A Quality Circle is a volunteer group composed of workers (or even students) who meet to discuss workplace improvement, and make presentations to management with their ideas, especially relating to quality of output in order to improve the performance of the organization, and motivate and enrich the work of employees. Typical topics are improving occupational safety and health, improving product design, and improvement in manufacturing process.

The ideal size of a quality circle is from eight to ten members.Quality circles have the advantage of continuity; the circle remains intact from project to project. (For a comparison to Quality Improvement Teams see Juran's Quality by Design[1].Quality circles were first established in Japan in 1962, and Kaoru Ishikawa has been credited with their creation. The movement in Japan was coordinated by the Japanese Union of Scientists and Engineers (JUSE).

The use of quality circles then spread beyond Japan. Quality circles have been implemented even in educational sectors in India and QCFI (Quality Circle Forum of India) is promoting such activities.

There are different quality circle tools, namely:
The Ishikawa diagram - which shows hierarchies of causes contributing to a problem 
The Pareto Chart - which analyses different causes by frequency to illustrate the vital cause
The PDCA-Deming wheel - Plan, Do, Check, Act, as described by W. Edwards Deming[edit]

==============================
Deuteronomy

1:11 (YHWH God of your fathers make you a thousand times so many more as ye are, and bless you, as he hath promised you!) 1:12 How can I myself alone bear your cumbrance, and your burden, and your strife? 1:13 Take you wise men, and understanding, and known among your tribes, and I will make them rulers over you.
1:14 And ye answered me, and said, The thing which thou hast spoken is good for us to do.
1:15 So I took the chief of your tribes, wise men, and known, and made them heads over you, captains over thousands, and captains over hundreds, and captains over fifties, and captains over tens, and officers among your tribes.
1:16 And I charged your judges at that time, saying, Hear the causes between your brethren, and judge righteously between every man and his brother, and the stranger that is with him.
1:17 Ye shall not respect persons in judgment; but ye shall hear the small as well as the great; ye shall not be afraid of the face of man; for the judgment is God's: and the cause that is too hard for you, bring it unto me, and I will hear it.

What about it OLD BITCHES?  Maybe single moms can raise their sons to rap this way? Then Bros can have their Hos?  Music to my ears;)   Entertainment to Save Our Planet, Sweetie.

Marie Cocco's Misogyny opinion in the Washington Post said there are T-Shirts that say this.  So it's really true, what Imus said dying black boys say when they watch females in sports.  And then that "sweetie" remark.  Well, that's  all perfectly normal.  Just read the Bible,  Sirach 25 and 26.  Especially in Spanish.  Machismo until 1920, 19th amendment on the Planet Earth.  It's Eve's fault.  Eve is mommy.  How about Barack's little "sweeties"  and his big one too?

http://www.webmd.com/news/20000810/alzheimers-take-two-
ibuprofen-call-me-in-morning

I'm watching C-SPAN3 on Alzheimer's as I write this.  I don't like taking medications.  If a drug makes me feel good right away, I get suspicious that I'll get addicted.  I took a prescription drug for my arthritis which made me feel good.  Then, I remembered that ibuprofen OTC was for pain.  So I started experimenting.  Lo and behold, I felt good.  Then I started worrying, how would I not want to feel that good.  It's been at least 3 years and when I feel good, well, I don't feel bad and so I forget about medicine.  Sometimes, I hurt for days before I remember I don't have to.  I've got ibuprofen.  I only take at most 1, 3 times a day.  Hardly ever though.  It's something that I can manage myself.  It started helping me not feel depressed the rare time I do feel depressed.  I do think that inflammation does occurs lots of time but we don't recognize it.  There probably are plenty of invisible terrorists insides us. I think depression can be a symptom of invisible inflammation.   
So last month when a newsletter mentioned ibuprofen is being researched for Alzeheimer's, that gave me confidence in my own observation.  This article says they aren't completely sure why it   appears to be working with mice. 

I'm certainly anxious to find out if they can trace ibuprofen throughout our bodies.  Some of the NSAIDs don't work for me and cause additional problems.  For some reason, ibuprofen works for me. I just took one without water and it's burning inside me.  That's a no no.  I should have not been so negligent with myself.    I will say this, I've never smoked.  I've only gotten intoxicated twice in my life.  Intoxication in me means that I can't  judge distances when driving or I vomit.  I experienced one each:)   I think eating and drinking and smoking habits do define differences in medication reactions.

Time is of the Essence
Pendulum clockFrom Wikipedia, the free encyclopedia
A pendulum clock is a clock that uses a pendulum, a swinging weight, as its time base. From its invention in 1656 by Christiaan Huygens until the 1930s, the pendulum clock was the world's most accurate timekeeper, accounting for its widespread use.[1] [2] Pendulum clocks must be stationary to operate; any motion or accelerations will affect the motion of the pendulum, causing inaccuracies, so other mechanisms must be used in portable timepieces. They are now kept mostly for their decorative and antique value.

Pendulum clock designed by Galileo Galilei

Vienna regulator style pendulum wall clock

[edit]History

The second pendulum clock built by Christiaan Huygens,
 in 1673.The pendulum clock was invented and patented by Christiaan Huygens in 1656, inspired by investigations of pendulums by Galileo Galilei beginning around 1602. Galileo discovered the key property that makes pendulums useful timekeepers: isochronism, which means that the period of swing of a pendulum is approximately the same for different sized swings.[3][4] Galileo had the idea for a pendulum clock in 1637, partly constructed by his son in 1649, but neither lived to finish it.[5] The introduction of the pendulum, the first harmonic oscillator used in timekeeping, increased the accuracy of clocks enormously, from about 15 minutes per day to 15 seconds per day[6]leading to their rapid spread as existing clocks were retrofitted with pendulums.

These early clocks, due to their verge escapements, had wide pendulum swings of up to 100°. Huygens discovered that wide swings made the pendulum inaccurate, causing its period, and thus the rate of the clock, to vary with changes in the driving force. Clockmakers' realization that only pendulums with small swings of a few degrees are isochronous motivated the invention of the anchor escapement in 1670, which reduced the pendulum's swing to 4°-6°.[7] This allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. The 'seconds' pendulum (also called the Royal pendulum) in which each swing takes one second, which is about one metre (39.1 in) long, became widely used. The long narrow clocks built around these pendulums, first made by William Clement around 1680, became known as grandfather clocks. The increased accuracy resulting from these developments caused the minute hand, previously rare, to be added to clock faces beginning around 1690.[8]

Until the 1800s, clocks were handmade by individual craftsmen and were very expensive. The rich ornamentation of clocks of this period indicates their value as status symbols of the wealthy. By the 1800s, factory production of clock parts gradually made pendulum clocks affordable by middle class families.

Daily life was organized around the home pendulum clock. More accurate pendulum clocks, called regulators, were installed in places of business and used to schedule work and set other clocks. The most accurate, known as astronomical regulators, were used in observatories. Beginning in the Industrial Revolution, astronomical regulators in naval observatories served as primary standards for national time distribution services.[9] From 1909, US National Bureau of Standards (now NIST) based the US time standard on Riefler pendulum clocks, accurate to about 10 milliseconds per day. In 1929 it switched to the Shortt free pendulum clock before phasing in quartz standards in the 1930s.[10] [11] With error less than one second per year, the Shortt was probably the most accurate commercially produced pendulum clock.

Pendulum clocks remained the world standard for accurate timekeeping for 270 years, until the invention of the quartz clock in 1927, and were used as standards through World War 2. The most accurate pendulum clock to date may be the Littlemore clock, built by Edward T. Hall in the 1990s.[12]

[edit]Mechanism
All mechanical pendulum clocks have these five parts[13]:

a power source; either a weight on a cord that turns a pulley, or a mainspring

a gear train that steps up the speed of the power so that the pendulum can use it

an escapement that gives the pendulum precisely timed impulses to keep it swinging and which releases the gear train in a step-by-step fashion

the pendulum, a weight on a rod

an indicator or dial that records how often the escapement has rotated and therefore how much time has passed, usually a traditional clock face with rotating hands.

More elaborate pendulum clocks may include these complications:

Striking train - strikes a chime on every hour, with the number of strikes equal to the number of the hour. More elaborate types strike on the quarter hours, and may play tunes, usually Westminster quarters.

Repeater attachment - repeats the hour chimes when a knob is pressed. This rare complication was used before artificial lighting to check what time it was at night.

Calendar dials - show the day and date

Moon phase dial - Shows the phase of the moon with a painted picture of the moon on a rotating disk.

In electromechanical pendulum clocks the power source and gear train are replaced by a solenoid that provides the impulses to the pendulum by electromagnetic force and the escapement is replaced by a switch or photodetector that senses when the pendulum is in the right position to receive the impulse. In this case the pendulum controls the timekeeping. These should not be confused with more recent quartz pendulum clocks in which an electronic quartz clock module swings a pendulum. These are not true pendulum clocks because the timekeeping is controlled by a quartz crystal in the module and the swinging pendulum is merely a decorative simulation.

[edit]Gravity-swing pendulum

Schoolhouse regulator style pendulum wall clock

The pendulum swings with a period that varies with the square root of its effective length. The rate of pendulum clocks is adjusted by moving the pendulum bob up or down on its rod, often by means of an adjusting nut under the bob. In some pendulum clocks, fine adjustment is done with an auxiliary adjustment, which may be a small weight that is moved up or down the pendulum rod, or a small tray mounted on the rod where small weights are placed or removed to change the effective length.

[edit]Thermal compensation

To keep time accurately, pendulums are usually made to not vary in length as the temperature changes. Owing to the expansion of metal, the length of a simple pendulum will vary with temperature, slowing the clock as the temperature rises. Early high-precision clocks used the liquid metal mercury to lift a portion of the pendulum mass in compensation for the increased length of the suspension. John Harrison invented the gridiron pendulum, which uses a sliding "banjo" of solid metals with differing thermal expansion rates such as brass or zinc and steel to achieve a zero-expansion pendulum while avoiding the use of toxic mercury.

By the end of the nineteenth century, materials were available that had a very low inherent change of length with temperature and these were used to make a simple pendulum rod. These included Invar, a nickel/iron alloy; and fused silica, a glass. The latter is still used for pendulums in gravimeters.

[edit]Atmospheric drag

The viscosity of the air through which the pendulum swings will vary with atomspheric pressure, humidity, and temperature. This drag also requires power that could otherwise be applied to extending the time between windings. Pendulums are sometimes polished and streamlined to reduce the effects of air drag (which is where most of the driving power goes) on the clock's accuracy. In the late 19th century and early 20th century, pendulums for clocks in astronomical observatories were often operated in a chamber that had been pumped to a low pressure to reduce drag and make the pendulum's operation even more accurate.[edit]Local gravity

Since the pendulum rate will increase with an increase in gravity, and local gravity varies with latitude and location on Earth, pendulum clocks must be readjusted to keep time after a move. Even moving a clock to the top of a tall building will cause it to lose measureable time due to lower gravity.[edit]Torsion pendulum
Main article: Torsion pendulum clock

Also called torsion-spring pendulum, this is a wheel-like mass (most often four spheres on cross spokes) suspended from a vertical strip (ribbon) of spring steel, used as the regulating mechanism in torsion pendulum clocks. Rotation of the mass winds and unwinds the suspension spring, with the energy impulse applied to the top of the spring. As the period of a cycle is quite slow compared to the gravity swing pendulum, it is possible to make clocks that need to be wound only every 30 days, or even only once a year. A clock requiring only annual winding is sometimes called a "400-Day clock", "perpetual clock" or "anniversary clock", the latter sometimes given as a wedding memorialisation gift. Schatz and Kundo, both German firms, were once the main manufacturers of this type of clock. This type is independent of the local force of gravity but is more affected by temperature changes than an uncompensated gravity-swing pendulum.

[edit]Escapement
Main article: escapementThe escapement drives the pendulum, usually from a gear train, and is the part that ticks. Most escapements have a locking state and a drive state. In the locking state, nothing moves. The motion of the pendulum switches the escapement to drive, and the escapement then pushes on the pendulum for some part of the pendulum's cycle. A notable but rare exception is Harrison's grasshopper escapement. In precision clocks, the escapement is often driven directly by a small weight or spring that is re-set at frequent intervals by an independent mechanism called a remontoire. This frees the escapement from the effects of variations in the gear train. In the late 19th century, electromechanical escapements were developed. In these, a mechanical switch or a phototube turned an electromagnet on for a brief section of the pendulum's swing. These were used on some of the most precise clocks known. They were usually employed with vacuum pendulums on astronomical clocks. The pulse of electricity that drove the pendulum would also drive a plunger to move the gear train.

In the 20th century, W.H. Shortt invented a free pendulum clock with an accuracy of one-hundredth of a second per day. In this system, the timekeeping pendulum does no work and is kept swinging by a push from a weighted arm (gravity arm) that is lowered onto the pendulum by another (slave) clock just before it is needed. The gravity arm then pushes on the free pendulum, which releases it to drop out of engagement at a time that is set entirely by the free pendulum. Once the gravity arm is released, it trips a mechanism to reset itself ready for release by the slave clock. The whole cycle is kept synchronised by a small blade spring on the pendulum of the slave clock. The slave clock is set to run slightly slow, and the reset circuit for the gravity arm activates a pivoted arm that just engages with the tip of the blade spring. If the slave clock has lost too much time, its blade spring pushes against the arm and this accelerates the pendulum. The amount of this gain is such that the blade spring doesn't engage on the next cycle but does on the next again. This form of clock became the standard for use in observatories from the mid-1920s until superseded by quartz technology.

[edit]Time Indication
The indicating system is almost always the traditional dial with moving hour and minute hands. Many clocks have a small third hand indicating seconds on a subsidiary dial. Pendulum clocks are usually designed to be set by manually pushing the minute hand around the dial to the correct time. The minute hand is mounted on a slipping friction sleeve which allows it to be turned on its arbor. The hour hand is driven not from the main train but from the minute hand's shaft through a small set of gears, so rotating the minute hand manually also sets the hour hand.

[edit]See also

The Invention of ClocksThe (Not So) Simple PendulumCategories: Clocks | Horology | Pendulumsarticle discussion edit this page history

This page was last modified on 10 May 2008, at 01:31. All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.Privacy policy About Wikipedia DisclaimersMake a donation to Wikipedia and give the gift of knowledge!

The Planet Earth is awaiting the Prince of Light.  Who is this human being?  The true Messiah?  The person who "creates" an Arabic InterLinear Qur'an into Hebrew and puts it on the Web somewhere for free download.  Then the whole U.N. protects this "creation".  Watch the atmosphere evolve after that "creation".