Acrobat

Program developed by US graphics company Adobe to allow users of different types of computers to view the same documents complete with graphics and layout. Launched in 1993, Acrobat was designed to get around the limitations of existing systems when transferring data between different types of computers, which typically required all formatting to be stripped from the documents. The file format created by Adobe Acrobat is PDF (portable document format).

The program to generate the code that makes the documents transferable with formatting intact must be bought, but the program for reading the documents is available free of charge. One of Acrobat's strengths is its ability to include hyperlinks within the document. As a hypertext development tool it rivalled early developments on the World Wide Web.

By the late 1990s Acrobat was in common use on the Internet for distributing certain types of company documents, and the program had been enhanced to integrate with Web browsers. In 2000, Adobe bought the electronic-book company Glassbook, whose Glassbook Reader software could read Acrobat PDF files. In 2001, Adobe launched its Adobe Acrobar eBook Reader, incorporating Glassbook reader technology.

Acrobat coding was designed to turn computers into information distributors that would allow personal computer users to view a document in its original form. It can be generated directly from PostScript files.

acrobat

Entertainer who performs difficult feats of jumping, falling, and balancing, usually in a circus. Acrobats, or more properly contortionists, who twist their bodies into seemingly impossible positions and walk on their hands, were known to the classical world and are often found depicted in medieval manuscripts. Modern acrobats specialize in forming human pyramids, tightrope (or wire) walking, and trapeze acts.

Balancing acts Equilibrists balance themselves on high poles or on some such apparatus as the unicycle. Risley acts consist of balancing objects like a ball or barrel, or a small child, on the feet while lying on one's back, rotating them and throwing them into the air and catching them again. In a double act they are thrown from one partner to another. Tightrope (or wire) walkers (in modern times a wire has superseded the earlier rope) often perform high above the ground, balancing themselves with the help of a weighted pole. The best-known 19th-century tightrope walker was Charles Blondin but his feats have been superseded by later performers, such as the Italian Con Colleano (1910– ) who could throw a forward somersault on the wire. In the days of the music hall, wire walkers usually performed on the slack wire, sometimes using a parasol to maintain their equilibrium.

Leaping acts The trampoline act is also a feat of acrobatics, in which the performer bounces on a spring mattress, turning and somersaulting in the air, rising higher and higher as he or she gains momentum. Other means of assisting the performer to leap higher are the springboard, or teeter board, and the Russian swing; with the aid of these acrobats will often form a four-person-high column, executing somersaults during their leaps.

Trapeze acts Trapeze artists usually form the most sensational part of any circus or entertainment in which they appear. They work high in the air, and since a slip might prove fatal, they have a protective net below them. Their act consists in swinging on a trapeze from which the ‘fliers’ launch themselves at full speed, turning somersaults in midair, to catch another trapeze or be caught by the ‘catchers’, who usually hang upside down by their knees. The first trapeze artist to make an impact on the public as an individual was the French Jules Léotard (died 1870). Later ones were the Clarkes, the Concellos, and the Codonas, who performed a triple somersault between trapezes.

Other acts There are other types of acrobatic acts on ladders, on balls controlled by the feet, or on bicycles. Tumblers, who fall backwards and forwards and head over heels, are also acrobats, and tumbling forms part of the act of the true clown.