Kathleen Chang was an eccentric to some and a valiant voice for social justice to others, but she was hard to ignore: in the summer, she wore a bikini to her protests, in the winter, leotards. Sometimes it was a suit of faux marijuana to grab attention for the one-woman political demonstrations she staged for 15 years on the University of Pennsylvania campus.

On Tuesday, feeling that her cause for social ''transformation'' was not getting through, Ms. Chang, 46, held her final protest. At 11:20 A.M., as students walked across campus or sat on the green, she stood before a sculpture of a peace sign, poured a bucket of gasoline over her thin frame and set herself afire. She was pronounced dead shortly afterward.

Today, there was little mystery on campus about why she chose self-immolation: like Ms. Chang's politics, her suicide was entirely public, explained in great detail in a packet she handed out to friends and news organizations on Tuesday morning.

''This is the tactically correct move,' she wrote. ''I feel it with all the weight of my soul.''

But there was still a sense of loss, and uneasiness, over this unorthodox woman who had become as much a part of the campus as the sculpture where she chose to hold her demonstrations. By late afternoon, as a light rain started to fall, the peace sculpture had collected more than a dozen bouquets, strands of beads, as well as a poem that began: ''Maybe she really was a nut, the girl said. But I don't think so.''