San Francisco -- Something important was proved Tuesday in San Francisco when a young man strapped himself into a lawn chair tied to a strand of flimsy balloons and floated 50 feet above Potrero Hill.

It was not a stunt, said the man in the chair. It was a scientific experiment.

No one knew exactly what was proved, however. Perhaps it was that latex can burst under pressure, a concept already well known in San Francisco.

The idea, if there was one, was to recreate the 1982 flight of "Lawn Chair Larry" Walters, the Los Angeles truck driver who flew a similar rig 16,000 feet into the sky above Southern California and lived to tell about it. An Australian TV company had commissioned the joyride for an upcoming special on urban legends.

"Nothing can go wrong," said stuntman Adam Savage, preparing to go aloft, while a large number of things that could not go wrong kept going wrong.

The latex balloons, purchased for $10 apiece from a surplus store, had an unsettling knack of bursting during inflation. At least six of them popped before Savage had even taken his place in the chair.

Then the balloons turned out to need twice as much helium to fill as Savage originally calculated, and extra gas cylinders had to be scrounged. Then, with only minutes before lift-off, the batteries on the emergency walkie-talkies went out.

"I need some triple-A batteries!" the balloonist yelled. "Somebody go check the deli! Maybe they have some!"

Meanwhile, more balloons popped.

"It's not making me nervous," Savage said, nervously, as the latex shards drifted to earth. "I suppose these balloons have outlived their shelf life. That's why they were only $10 each."

After a quick review of the flight plan with the TV producer ("You go up, then you come down"), Savage climbed into the lawn chair ($29 from Sears), strapped on his safety harness (borrowed from a Mission District climbing gym) and gazed up at his towering string of balloons, which resembled a strand of giant Vidalia onions glistening in the morning sun.

Shortly before 9 a.m., helpers began removing sandbags and releasing their hold on three ropes tethering the chair to parked cars. Savage, not quite sure how to control the proceedings, began to rise slowly into the sky and drift gently over Missouri Street, like the Wizard of Oz making his getaway.

The TV crew said Savage had soared to a height of 100 feet, but less partial observers placed the altitude at about half that. The walkie-talkie failure was never a factor, as air-to-ground communication was conducted largely by shouting.

The greatest humiliation occurred midway into the flight, when Savage downed a beer and, after warning observers below to stand clear, dropped the bottle over the side. The bottle failed to break on impact, clearly indicating to all the less-than-life-threatening height of Savage's lawn chair.

"Better have another beer!" someone yelled.

Meanwhile, a modest crowd of gawkers gathered on Missouri Street to take in the spectacle, such as it was. Dogs barked, drivers honked and passers-by giggled.

After 12 minutes aloft, the TV cameraman had recorded sufficient footage, and there was no good reason for the flight to continue. One by one, Savage fired a BB gun at the balloons and the chair descended, as Sir Isaac predicted it would.

Back on the ground, Savage reached for a celebratory cigar and basked in what accolades there were. He said it had been eerie to ride his lawn chair on the same day that balloonist Steve Fosset completed his round-the-world solo flight, although that comparison seemed more of a stretch than anything that happened to the latex.

"I'm just glad it turned out OK," said Ed Wallace, manager of the electrical warehouse next door whose airspace Savage had drifted into. "It didn't make any sense at all. He said he had the whole thing worked out perfectly, but it didn't look that way. The potential for him getting hurt was pretty good."