Arguing in a plaintive voice that "there's no way we can survive" because "we've been so betrayed" by defectors who made it safely out of Jonestown, cult leader Jim Jones had to summon all his oratorical power to shout down dissenters and force his 900 remaining followers to commit mass suicide.

An extraordinary tape recording of the first 45 minutes of the "white night" of Saturday, Nov. 18 -- which is filled with children's screams, Jones' amplified exhortations and shouted arguments among his followers -- shows that many of them were very reluctant to follow his orders to drink poison.

But Jones told them Jonestown defectors who had survived an armed ambush of the fact-finding mission of Rep. Leo J. Ryan (D-Calif.) at the nearby Port Kaituma airstrip would "get back to the states and criticize Jonestown. They'll make our lives like hell...

"We are sitting on a powder keg," Jones shouted to his followers, who had been massed around him by Jonestown guards armed with guns and crossbows. "If we can't live in peace, let's die in peace."

The tape, which was recorded on a machine Jones kept next to his wooden throne chair on the stage of Jonestown's open-air pavilion to record his almost nightly harangues there, provides U.S. and Guyanese investigators with the best evidence yet of just how the forced mass suicide was carried out.

FBI technicians in Washington and police officials in the Guyanese capital of Georgetown are now studying copies of the tape and making transcripts. The tape was found by a State Department representative on a tour of Jonestown a day or two after the massed dead were discovered there, according to law enforcement sources who provide The Washington Post with a detailed account of the tape's contents.

U.S. and Guyanese investigators also found "mountains of other tape recordings" and more than 5,000 pages of Peoples Temple Church "political, financial and internal documents" in Jonestown, according to the sources. Most of this evidence reportedly is still in the hands of Guyanese authorities, who also recovered an estimated $1 million in U.S. and Guyanese currency in and around Jonestown.

According to the sources familiar with the 45-minute tape recording of Jones urging his followers to take the poison, Jones had considerable difficulty persuading all 900 to join him in death. Sounds of continued arguing made it clear that the killing was far from finished when the tape apparently ran out.

The tape began, according to the sources, with the sounds of church music and children talking and crying. This apparently was when the residents of Jonestown were herded around Jones and encircled by the armed guards at one end of the pavilion, as witnesses have already reported.

Jones' exhortations and the shouted rejoinders and arguments from various individuals in the crowd were punctuated frequently by loud bursts of applause, according to the sources' account of the tape.

"I tried to give you a good life," Jones began. "In spite of all I tried to do, a handful of our people who are alive have made our lives impossible."

He apparently was referring to the men, women and children who had left Jonestown with Ryan's party that afternoon and had survived the ambush by the gunmen Jones sent to kill them all. Ryan, one of the Jonestown defectors and three journalists were killed in the gunfire at the Port Kaituma air strip. But the rest of the group of about 30 U.S. and Guyanese officials, journalists and Jonestown defectors survived, and Jones had just learned that from the gunmen on their return to Jonestown.

"There's no way to detach ourselves from what's happened today," Jones told his followers. Later, in what was described as a very anguished tone of voice, he added: "We've been so betrayed."

After explaining that the surviving defectors would make too much trouble for Jonestown after they returned to the United States and told their story, Jones said, "I propose that we not commit suicide but a revolutionary act" by taking the poison.

In "white night" rehearsals in previous months, Jones had told his followers that suicide would be the only way they could deny ultimate victory to enemies who would invade them from the surrounding jungle.

"So my opinion is to be good to the children and seniors," Jones said, as he urged that the babies and elderly be administered the poison first by the able-bodied adults.

When many of the children began screaming, Jones repeatedly asked the adults to settle them down and keep them quiet. He told the adults to administer the poison to the children by spraying it down the backs of their throats, apparently with the syringes found later at the death scene.

Many of the adults also shouted their objections to the mass suicide. One woman said she did not mind dying if her son could live. Others argued that the best way was to stay alive and fight.

But Jones was joined by others in the crowd in shouting down these dissenters.

"Dad," someone shouted, referring to Jones, "has brought us this far. My vote is to go with Dad."

Jones also appeared from the tape to be arguing with his wife, Marceline, about the mass suicide. According to the sources, those who have listened to the tape closely believe Jones was shouting at her scoldingly when he kept repeating the words, "Mother, Mother, Mother..."

"Mother" is what Jones and others in Jonestown called Marceline, just as everyone referred to Jones himself as "Father" or "Dad."

Earlier, officials and journalists had theorized that Jones was calling out to his own mother, who had died at Jonestown a year earlier and was buried there.

As the tape ran out, according to the sources, it appeared from the cacophony of screaming that many people had drunk the poison, or had it forced down them, while Jones still could be heard arguing with others to take it.

Some listeners also have heard what sounded like gunfire, according to the sources, but they are not certain after repeated hearings of the tape whether it was gunfire or other sounds reverberating in the pavilion. Sounds are somewhat garbled at various places on the tape, according to the sources, although its overall quality is considered remarkably good.

Jones died on the steps of his throne on the pavilion stage of gunshots wounds. Although a handgun was found near him, authorities are not yet certain whether he took his own life.

Two other Jonestown residents were found dead of gunshot wounds elsewhere in the encampment. The rest of the more than 900 victims are believed to have been killed by the poison, including the security guards, whose weapons were found alongside them.

Besides the tape recorder, Jones had filled Jonestown with sophisticated electronic devices. There was a closed-circuit television system, reportedly including video taping capabilities, although no videotapes set have been reported among the possessions found in Jonestown.

Most of this expensive equipment had been left untouched Guyana and U.S. soldiers, Guyanese who lived near Jonestown and journalists. Some of the visitors, including soldiers and journalists, looted the site of clothes, letters and other documents before Guyanese soldiers finally sealed it off.

Guyanese authorites reportedly have decided to confiscate all of Jonestown's facilities and some, if not all, of the cash found there.

No decision has been made yet on what use to make of Jonestown. Guyanese officials have discussed various possibilities from leaving it as museum or tourist attraction to using it for a military encampment or government-run agricultural installation.