Microsoft told a federal appeals court Monday that it must close to the public pretrial testimony in the government's antitrust case against it or risk creating a "media circus" that will only hamper its efforts to prepare for trial next month. In its request for a stay pending a more complete appeal, the world's largest make of desktop PC software conceded that a 1913 law required depositions taken in Sherman antitrust cases must be open to the public. Nonetheless, Microsoft attorneys said the use of the word "depositions" in that law referred only to testimony taken by groups of travelling "masters" who took testimony in the field in lieu of testimony in a public court. The use of depositions for simple discovery, that is, the uncovering of evidence to be used in a later trial, was not covered by the 1913 law, Microsoft lawyers claimed. Microsoft's request came as a result of last week's ruling by U.S. District Judge Thomas Penfield Jackson that media and other spectators must be allowed to view depositions of Microsoft officials and others before the trial begins. The ruling was in response to a request for access to the proceedings by The New York Times, Seattle Times, and Ziff Davis. Microsoft asked the appeals court for a stay of the ruling after Jackson declined to issue a stay himself. Though Microsoft has argued the media could read edited transcripts or view edited videotapes after the testimony is given, Jackson ruled such accommodations would not comply with the 1913 law. He told both sides last week to make arrangements for testimony so that spectators could leave the room when testimony over proprietary information arose. Alternately, he said, each side could work out a way of discussing proprietary information during testimony without disclosing too many specifics to spectators. The U.S. Department of Justice and states have accused Microsoft of illegally using its monopoly over the PC operating system to establish similar control over the market for Internet software.