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[[Image:Roger_Federer.jpg|thumb|left|{{#ifexist:Template:Roger Federer.jpg/credit|{{Roger Federer.jpg/credit}}<br/>|}}Roger Federer, a professional tennis player, hitting a forehand against James Blake in the quarterfinals of the 2006 U.S. Open.]]
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<small>
'''Tennis''' is a sport played between either two players ("singles") or two teams of two players ("doubles"). Players use a stringed racquet to strike a hollow rubber ball covered with felt over a net into the opponent's court. In some places tennis is still called '''lawn tennis''' to distinguish it from ''real tennis'' (also known as ''royal tennis'' or ''court tennis''), an older form of the game that originated in France in the Middle Ages and is played indoors on a very different court. Originating in England in the late nineteenth century, lawn tennis first spread throughout the English-speaking world, particularly among the upper classes. Today tennis is an Olympic sport that is played at all levels of society, by all ages, and in many countries around the world.  Except for the adoption of the tie-breaker in the 1970s, its rules have remained remarkably unchanged since the 1890s.  Millions of people also follow tennis as a spectator sport, especially the four Grand Slam tournaments.
==Footnotes==
 
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===Manner of play===
</small>
====The court====
Tennis is played on a rectangular, flat surface that can be composed of various materials.  The court is 78 feet (23.77 meters) long and its width is 27 feet (8.23 m) for singles matches and 36 feet (10.97 m) for doubles matches. Additional clear space around the court is required in order for players to reach balls. A net is stretched across the full width of the court, parallel with the baselines, dividing it into two equal areas. The net is 3 feet 6 inches (1.07 m) high at the posts and 3 feet (914 mm) high in the center.
 
=====''The lines''=====
The two lines that delineate the width of the court are called the baseline.  The short mark in the center of each baseline is referred to as either the hash mark or the center mark.  The outermost lines that make up the length are both called the doubles sideline.  These are the boundaries used when doubles is being played.  The area between the doubles sideline and the lines next to them is called the doubles alley, which is considered to be "out" in singles play.  These lines next to the doubles sideline are the singles sidelines, and are used as boundaries in singles play.  The line that runs across the center of a player's side of the court is called the service line; despite its name this is not where a player legally stands when making a serve.  The line dividing the service line in two is called the center line or center service line.  The boxes that this center line creates are called the service boxes; depending on a player's position, they will have to hit the ball into one of these when serving.

Latest revision as of 10:19, 11 September 2020

The Irvin pin. The eyes have always been red, but there are urban legends about the meanings of other colors.
A pin from another company, possibly Switlik or Standard Parachute. This style is common in catalogs and auctions of military memorabilia.

The Caterpillar Club is an informal association of people who have successfully used a parachute to bail out of a disabled aircraft. After authentication by the parachute maker, applicants receive a membership certificate and a distinctive lapel pin.

History

Before April 28, 1919 there was no way for a pilot to jump out of a plane and then to deploy a parachute. Parachutes were stored in a canister attached to the aircraft, and if the plane was spinning, the parachute could not deploy. Film industry stuntman Leslie Irvin developed a parachute that the pilot could deploy at will from a back pack using a ripcord. He joined the Army Air Corps parachute research team, and in April 1919 he successfully tested his design, though he broke his ankle during the test. Irvin was the first person to make a premeditated free fall jump from an airplane. He went on to form the Irving Airchute Company, which became a large supplier of parachutes. (A clerical error resulted in the addition of the "g" to Irvin and this was left in place until 1970, when the company was unified under the title Irvin Industries Incorporated.) The Irvin brand is now a part of Airborne Systems, a company with operations in Canada, the U.S. and the U.K.[1].

An early brochure [2] of the Irvin Parachute Company credits William O'Connor 24 August 1920 at McCook Field near Dayton, Ohio as the first person to be saved by an Irvin parachute, but this feat was unrecognised. On 20 October 1922 Lieutenant Harold R. Harris, chief of the McCook Field Flying Station, jumped from a disabled Loening W-2A monoplane fighter. Shortly after, two reporters from the Dayton Herald, realising that there would be more jumps in future, suggested that a club should be formed. 'Caterpillar Club' was suggested because the parachute canopy was made of silk, and because caterpillars have to climb out of their cocoons and fly away. Harris became the first member, and from that time forward any person who jumped from a disabled aircraft with a parachute became a member of the Caterpillar Club. Other famous members include General James Doolittle, Charles Lindbergh and (retired) astronaut John Glenn.

In 1922 Leslie Irvin agreed to give a gold pin to every person whose life was saved by one of his parachutes. By 1945 the number of members with the Irvin pins had grown to over 34,000. In addition to the Irvin Air Chute Company and its successors, other parachute manufacturers have also issued caterpillar pins for successful jumps. Irvin/Irving's successor, Airborne Systems Canada, still provides pins to people who made their jump long ago and are just now applying for membership. Another of these is Switlik Parachute Company, which though it no longer makes parachutes, still issues pins.

Footnotes

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